• G. Tosin, R. Basílio, J.F. Citadini, L. Liu, M. Potye, M.C. Rocha, P.P. Sanchez, E.W. Siqueira
  LNLS, Campinas

"Green solutions" using permanent magnets are being proposed for the dipoles and quadrupoles of the second Brazilian Synchrotron Light Source - LNLS2 - magnetic lattice. The main purpose is to reduce as much as possible the electrical energy consumption, assuring the reliability of the magnets during several years. Sextupoles will have multiple functions due to the limited space in the lattice design.

• L.O. Dallin, D.G. Bilbrough
  CLS, Saskatoon, Saskatchewan

To investigate the effect of an elliptically polarized undulator (EPU) on the dynamic aperture of storage ring a model is required for use in an optics code. An EPU can be modelled as an array of skew dipole magnets. The skew angle ranges from zero to ninety degrees depending on the degree of polarization. Crudely the EPU can be modelled using alternating skew dipole blocks. A model that better reproduces the sinusoidally varying fields can be achieved by slicing blocks into smaller subsets. Field roll-off produced by the limited transverse dimensions of the magnet blocks can be included as skew multipoles. For example the roll-off of the horizontal field in the vertical undulator mode is very nearly a skew sextupole. The model has the advantage of correctly calculating the path length through the EPU which is important for tracking in six dimensions.

• M.J. Sigrist, D.G. Bilbrough, S. Chen, L.O. Dallin, W.A. Wurtz
  CLS, Saskatoon, Saskatchewan

The Canadian Lightsource is a 2.9 GeV 3rd generation lightsource in Saskatoon, Canada. The latest expansion of operations includes adding 4 insertion devices in 2 straight sections. These devices will include a hybrid permanent magnet wiggler, an in-vacuum undulator and 2 APPLE-II type undulators. The 4 m long elliptical APPLE-II IDs will cover overlapping photon energy ranges of 15-200eV and 200-1000eV. These devices will be installed adjacent to one another in the same straight with the magnet arrays mounted on one support structure and a horizontal translation system to allow users to select one device at a time for use on a single beamline. The 2nd straight will include the hybrid wiggler and in-vacuum undulator in a 3 magnet chicane. The wiggler is designed to supply photons for a center beamline and a side beamline accepting radiation 5 mrad off of the centerline of the radiation fan. The critical energy of photons emitted of the sideline are >90% of the critical energy on the centerline. An 8 mrad center chicane magnet separates the photons of the undulator from the wiggler beamlines allowing for 3 beamlines operating with 2 IDs in a single straight section.

• C.W.O. Ostenfeld, M. Pedersen
  Danfysik A/S, Jyllinge

Danfysik A/S has built a cryogenic in-vacuum undulator for Diamond Light Source, with a period length of 17.7 mm and an effective K of 1.7 at cryogenic temperatures. The undulator is hybrid-type, with Vanadium Permendur poles and NdFeB poles. In order to verify the performance of the device under cryogenic conditions, an in-vacuum measuring system is required. We present the magnetic measurements at room temperature and under cryogenic in-vacuum conditions. The magnet assembly cannot be baked, due to a choice of high-remanence, low coercivity magnet grade. We discuss the vacuum performance of the undulator.

• C. Benabderrahmane, P. Berteaud, N. Béchu, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, C.A. Kitegi, J.L. Marlats, K. Tavakoli, M. Valléau, D. Zerbib
  SOLEIL, Gif-sur-Yvette

The production of hard X rays at SOLEIL, a 2.75 GeV, requires short period and small gap in-vacuum undulators. For shifting further the radiation toward higher energies, the peak magnetic field of the undulators can be further increased by cooling the permanent magnets at cryogenic temperature below 100 K. A R&D programme for the construction of a 2 m long 18 mm period CPMU is launched: the use of PrFeB enables to increase the peak magnetic field at a cryogenic temperature of 77 K. Praseodymium was chosen instead of Neodymium type magnets, because it prevents the appearance of the Spin Reorientation Transition. The magnetic characterisation of different permanent magnet grades at cryogenic temperatures (NdFeB and PrFeB), and the magnetic and thermal measurements on a small 4 period NdFeB cryogenic undulator are presented. The status on the progress of the CPMU conception is given. The magnetic and mechanical design, including the cooling of the girders at 77K, and the thermal budget are described. The designs of the dedicated magnetic measurement benches, which will be required to check the magnetic performance of the undulator at low temperature, are also reported.

• C.A. Kitegi, F. Briquez, M.-E. Couprie, T.K. El Ajjouri, J.-M. Filhol, K. Tavakoli, J. Vétéran
  SOLEIL, Gif-sur-Yvette

At SOLEIL, the production of high brilliant photon beams with adjustable polarization is achieved by means of Advanced Planar Polarized Light Emitter-II (APPLE-II) undulators. The HU36 is a short period high field APPLE-II type undulator with 36 mm period and 0.8 T peak field at a minimum gap of 11 mm. The HU36 circularly polarized radiation ranges from 2 keV to 5 keV, while the planar one extends up to 10 keV. High harmonic radiation (up to the 13th) is required to reach such high energy; therefore a small RMS phase error is needed. To enable closing the gap at 11 mm, the HU36 is planned to be installed in a short section where the large horizontal beta function imposes constraining tolerances on the integrated field errors. However at low period and high field, the magnet holders, commonly used at SOLEIL to maintain magnets on the girders, experience mechanical deformation due to the large magnetic forces. This results in the variation of field integrals when the shift between girders is changed. Solutions to minimize these errors are discussed and finally the HU36 magnetic performances are reviewed.

• O. Marcouillé, P. Berteaud, P. Brunelle, N. Béchu, L. Chapuis, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, A. Lestrade, J.L. Marlats, A. Mary, M. Massal, M.-H. Nguyen, K. Tavakoli, M. Valléau, J. Vétéran
  SOLEIL, Gif-sur-Yvette

The production of high fluxes in the hard X-rays region is a major issue on medium energy storage rings. It requires the installation of Insertion Devices with high magnetic field and a large number of periods. The construction of a superconducting wiggler has been first envisaged but reveals to be maintenance constraining, much more complex and expensive than the permanent magnet technology. A small gap in vacuum wiggler composed of 38 periods of 50 mm has been preferred. The compact magnetic system allows to produce in a limited space a magnetic field of 2.1 T in a small gap of 5.5 mm, whereas an auxiliary counterforce system based on non-magnetic springs compensate the magnetic forces (up to 8.5 Tons) acting between magnet arrays. The gap between jaws and the mechanical deformations have been controlled and corrected. Magic fingers corrections have been also performed to reduce the integrated multipoles and to minimize the 2nd order integrals resulting from the tight width of the wiggler poles. This paper presents the design of the wiggler, the construction, and the results of the measurements after magnetic corrections.

• J. Chavanne, L. Goirand, G. Lebec, C. Penel, F. Revol
  ESRF, Grenoble

An important upgrade of the ESRF is planned from 2009 to 2016. It is mainly driven by the improvement of beamlines performances and capacity. On the storage ring side, the length of the straight sections will be increased from 5 m to 6 m with a possible further extension to 7 m. These long sections will provide a higher photon flux, and it will allow the installation of canted undulators. The length of the insertion devices (ID), such as revolver undulators and in-vacuum undulators, will be modified to fit the first upgraded beamline sections. The resulting implication on the length of new IDs will be presented. The concept of canted undulators is a proposed optional feature. It will rely on novel permanent magnet chicane providing a maximal separation angle of 5.4 mrad while keeping short distance between canted undulators. Magnetic chicane magnets with low fringe field and homogeneous longitudinal field integral have been designed. The developed magnets will be presented.

• J. Bahrdt, W. Frentrup, A. Gaupp, M. Scheer, F. Schäfers, G. Wüstefeld
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin

At BESSY II photon energies above 2keV can be produced only with bending magnets, a permanent magnet wiggler, superconducting (SC) wavelength shifters and a SC-wiggler. The wiggler brilliance suffers from the depth of field effect and the bending magnets and wavelength shifters produce the X-rays only with a single pole. Experiments such as HIgh Kinetic Energy photoelectron spectroscopy (HIKE) or microspectroscopy on nanostructured materials demand a high brilliance and flux as it is provided by a small period cryogenic undulator. This paper discusses the requirements for the operation of small gap cryogenic devices at BESSY II. A scheme with two adjacent, vertical low beta sections inside of one of the long straight sections is suggested. The straight is divided into two parts by a quadrupole triple in the center. An optic with an increased, vertical beta tune by 0.5 is presently studied. The optics outside of the low beta section and the horizontal tune are kept unchanged.

• J. Bahrdt, H.-J. Baecker, M. Dirsat, W. Frentrup, A. Gaupp, D. Pflückhahn, M. Scheer, B. Schulz
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
• F.J. Grüner, R. Weingartner
  LMU, Garching
• D. Just
  Technische Universität Berlin, Berlin
• F.H. O'Shea
  UCLA, Los Angeles, California

In collaboration with the Ludwig-Maximilian-University Munich a cryogenic PrFeB- based undulator has been built. The 20-period device has a period length of 9mm and a fixed gap of 2.5mm. The undulator has recently been installed at the laser plasma accelerator at the Max-Planck-Institute for Quantenoptik. The operation of a small gap device at a high emittance electron beam requires stable magnetic material. A high coercivity is achieved with PrFeB- material which is cooled down to 50K. This temperature is 100K lower as compared to the temperature of a NdFeB-based cryogenic undulator. In this paper we present the mechanic and cryogenic design and compare the predictions with measured data. The results are extrapolated to a 2m-long variable gap undulator.

• H. Delsim-Hashemi, J. Roßbach
  Uni HH, Hamburg
• U. Englisch, T. Mueller, A. Schöps, M. Tischer, P.V. Vagin
  DESY, Hamburg
• I. Vasserman
  ANL, Argonne

A seeded free-electron laser (FEL) experiment at VUV wavelengths, called sFLASH, is being prepared at the existing SASE FEL user facility FLASH. Seed pulses at wavelengths around 35 nm from high harmonic generation (HHG) will interact with the electron beam in sFLASH undulators upstream of the existing SASE undulator section. In this paper the tuning results and performance of the sFLASH undulators are presented.

• P. Peiffer, A. Bernhard, F. Burkart, S. Ehlers
  KIT, Karlsruhe
• T. Baumbach, S. Gerstl, A.W. Grau, R. Rossmanith
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• D. Schoerling, D. Wollmann
  CERN, Geneva

The monochromaticity and intensity of synchrotron light emitted by undulators strongly depend on the undulator field quality. For the particular case of superconductive undulators it was shown recently that their field quality can be significantly improved by an array of coupled high temperature superconductor loops attached to the surface of the superconductive undulator. Local field errors induce currents in the coupled closed superconducting loops and, as a result, the hereby generated magnetic field minimizes the field errors. In previous papers the concept was described theoretically and a proof-of-principle experiment was reported. This paper reports results of the first quantitative measurement of the phase error reduction in a 12-period short model undulator equipped with a full-scale induction shimming system.

• P. Peiffer, A. Bernhard, F. Burkart, S. Ehlers, A. Keilmann
  KIT, Karlsruhe
• T. Baumbach, R. Rossmanith
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• D. Schoerling
  CERN, Geneva

In the superconductive undulator SCU14, installed at ANKA, time dependent drifts in the magnetic fields were observed*. Simulations with the software OPERA 3D showed, that the cause of these drifts might be leak and eddy currents in the iron body of the undulator caused by the time-varying currents and fields during current ramps, which slowly decay by ohmic losses. This assumption was crosschecked by measurements at different mockup bodies. This contribution discusses the results of the simulations and measurements and the consequential strategies for avoiding this effect.

* S. Ehlers et. al. "Magnetic field transients in superconductive undulators", in Proceedings of the Particle Accelerator Conference, Vancouver, 2009, to be published.

• S. Casalbuoni, T. Baumbach, S. Gerstl, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• C. Boffo, W. Walter
  BNG, Würzburg

A 1.5 m long superconducting undulator with a period length of 15 mm is planned to be installed in ANKA middle 2010 to be the light source of the new beamline NANO for high resolution X-ray diffraction. The key specifications of the system are an undulator parameter K higher than 2 (for a magnetic gap of 5mm) and a phase error smaller than 3.5 degrees. In order to characterize the magnetic field properties of the superconducting coils local field measurements have been performed by moving a set of Hall probes on a sledge in a liquid helium bath: the results are reported.

• S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• V. Baglin
  CERN, Geneva
• C. Boffo, G. Sikler
  BNG, Würzburg
• T.W. Bradshaw
  STFC/RAL, Chilton, Didcot, Oxon
• R. Cimino, M. Commisso, B. Spataro
  INFN/LNF, Frascati (Roma)
• J.A. Clarke, D.J. Scott
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• M.P. Cox, J.C. Schouten
  Diamond, Oxfordshire
• R.M. Jones, I.R.R. Shinton
  UMAN, Manchester
• A. Mostacci
  Rome University La Sapienza, Roma
• E.J. Wallén
  MAX-lab, Lund
• R. Weigel
  Max-Planck Institute for Metal Research, Stuttgart

One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source DIAMOND is under discussion. Here we describe the technical design report of this device and the planned measurements with beam.

• A.W. Grau, T. Baumbach, S. Casalbuoni, S. Gerstl, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe

Precise measurements of the magnetic properties of conventional, i.e., permanent magnet based insertion devices has undergone tremendous improvements over the past 10 to 15 years and initiated a new era in synchrotron light sources worldwide. A similar breakthrough is now necessary in the field of superconducting insertion devices. In this contribution we describe the planned instrumentation to perform magnetic measurements of the local field, the field integrals and the multipole components of superconducting undulator coils in a cold invacuum (cryogen free) environment.

• A.W. Grau, T. Baumbach, S. Casalbuoni, S. Gerstl, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• C. Boffo, W. Walter
  BNG, Würzburg

One of the advantages of superconducting insertion devices (IDs) with respect to permanent magnet IDs is the possibility to enlarge the spectral range by changing the period length by reversing the direction of the current in a part of the windings. In this contribution we report the first experimental test of this principle demonstrated on a 70mm NbTi mock-up coil with period tripling, allowing to switch between a 15mm period length undulator and a 45mm wiggler.

• C. Boffo, W. Walter
  BNG, Würzburg
• T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe

Superconducting insertion devices (IDs) are very attractive for synchrotron light sources since they allow increasing the flux and/or the photon energy with respect to permanent magnet IDs. Babcock Noell GmbH (BNG) completed the fabrication of a 1.5 m long unit for ANKA at KIT. The period length of the device is 15 mm for a total of 100.5 full periods plus an additional matching period at each end. The key specifications of the system are: a K value higher than 2 for a magnetic gap of 5 mm, the capability of withstanding a 4 W beam heat load and a phase error smaller than 3.5 degrees. The field performance of the magnets has been qualified with liquid helium in a vertical dewar. As a result of this test the local correction coils have been installed and the magnets inserted in the final cryostat. During the factory acceptance test, the conduction cooling operation has been qualified and at the moment the undulator is ready to be tested at KIT. This paper describes the main features of the system and the results of the factory acceptance tests.

• G. Lanfranco, P. Craievich, D. La Civita, G.L. Loda, A.A. Lutman, F. Pradal, G. Sostero, M. Stefanutti
  ELETTRA, Basovizza
• M. Canetti, F. Gangini
  RIAL VACUUM S.p.A, Parma

The FERMI@Elettra project at the ELETTRA Laboratory of Sincrotrone Trieste (ST), currently under construction, will be comprised of a linear accelerator and two Free-Electron-Laser beamlines (FEL1, FEL2). In order to deliver high-intensity VUV and soft X-ray pulses, permanent magnet undulators with 9 mm minimum variable gap will be used. The adopted vacuum chambers will have a 7 by 25 mm² elliptical internal cross-section. While manufacturing the vacuum chamber in aluminum helps reducing the resistive wall wakefield effects, the chamber inner wall surface quality is strongly correlated to the surface roughness wakefield component. We report on the results of the study to improve the wall surface finish and lower the roughness periodicity. The chamber manufacturing status and its alignment mechanism is also presented.

• S. Sasaki
  HSRC, Higashi-Hiroshima

More than a decade has past after the original quasi-periodic undulator (QPU) was proposed.* Until now, much work has been done to improve the QPU performance. One of the first most productive improvements was to introduce the quasi-periodicity in an electron trajectory by partially changing the field strength in a periodic undulator.** Also, a modification of creation theory of one-dimensional quasi-periodicity gave another degree of freedom to build this type of device.*** As the result, many different types of QPUs have been and will be installed in the synchrotron radiation facilities worldwide.**** In this paper, a new scheme of quasi-periodic undulator that has a different magnetic structure is proposed. This new QPU generates a slightly higher intensity radiation with higher harmonics pattern different from those of previous QPUs. This new scheme of QPU is achieved by introducing orthogonal field in each half-period in order to create additional phase delay of electron beam at certain positions predicted by the theory. We discuss about realistic magnetic configurations as well as possibilities and limitations of new-QPUs.

* Hashimoto, Sasaki, NIM A361, 611 (1995)
** Chavanne, et al, Proc EPAC98, p2213, Diviacco, et al, ibid, p2216
*** Sasaki, et al, Proc EPAC98, p2237
**** Steier, et al, Proc EPAC08, p2311

• S. Hirata
  Hiroshima University, Faculty of Science, Higashi-Hirosima
• S. Sasaki
  HSRC, Higashi-Hiroshima

Different form conventional periodic undulators, the quasi-periodic undulator (QPU) can radiate　irrational harmonics instead of rational harmonics. It suits with experiments that need highly monochromatic light after passing through the monochromator. For this reason, the QPU is used in many synchrotron radiation facilities all over the world. Recently, new type QPUs that generate radiation spectra different from those by conventional type QPU were proposed*,**. In principle, the shape of radiation spectrum from a new QPU is determined by magnetic field distribution having different quasi periodic pattern. However, calculated spectra using a realistic magnetic field are often different from those of theoretical expectation. In this paper, a detailed comparative study is conducted to examine why there are these differences, how to correct magnetic field to get predicted spectra that fit to the theory. In addition, a possibility of modifying the basis of theory is investigated. These results, new generation method of new quasi-periodicity, and magnetic field distribution to achieve the best performance are presented at the conference.

* S. Sasaki, Proceedings of PAC09, Vancouver, May, 2009.
** S. Sasaki, Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (in Japanese).

• T. Tanaka, H. Kitamura
  RIKEN/SPring-8, Hyogo
• A. Anghel, M. Bruegger, W. Bulgheroni, B. Jakob, T. Schmidt
  PSI, Villigen
• A. Kagamihata, T. Seike
  JASRI/SPring-8, Hyogo-ken

The cryogenic permanent magnet undulator (CPMU) is an insertion device in which permanent magnets are cooled down to cryogenic temperature (CT) to improve the magnetic performances. Although CPMUs are realized by a slight modification of in-vacuum undulators (IVUs), we have several technical challenges to be overcome. Among them, the most important one is how to ensure the magnetic performance, in other words, how to measure the magnetic field at CT, and how to correct it if necessary. A new method of the phase-error correction has been proposed at SPring-8, in which the gap variation is corrected by adjusting mechanically the in-vacuum beam. What is important in this method is that the correction can be done at CT without breaking the vacuum, i.e., an 'in-situ' field correction is possible. The correction method has been tested to check the feasibility using the new CPMU with a magnetic period of 14 mm and a magnetic length of 1.7 m constructed for Swiss Light Source. In this paper, the principle and results are described together with the details of the new measurement system SAFALI (self aligned field analyzer with laser instrumentation) for the field measurement of CPMUs.

• K. Harada, Y. Kobayashi, T. Miyajima, S. Nagahashi, T. Obina, M. Shimada, R. Takai
  KEK, Ibaraki
• S. Matsuba
  Hiroshima University, Graduate School of Science, Higashi-Hiroshima

The fast local bump system for the helicity switching of variably polarizing undulators has been developed at the Photon Factory ring. The system consists of two APPLE-II type variably polarizing undulators and five identical horizontal kicker magnets for local bump with four small corrector magnets to prevent the leakage of the bump. At present, one undulator and the local bump system with corrector magnets are installed. For beam test, the system was operated with frequency up to 50 Hz with feed forward correction. In this presentation, after brief description of the system configuration, the results of the test operation and fine tunings of the fast local bump system are shown.

• K. Tsuchiya, T. Aoto
  KEK, Ibaraki

We have been developing a rapid-polarization-switching source at the B15-16 straight section in the PF 2.5GeV ring. The source consists of tandem two APPLE-II type elliptically polarizing undulators (EPU), namely U#16-1 and U#16-2, and a fast kicker system. These two undulators are designed to obtain the soft x-ray at the energy region from 200eV to 1keV with various polarization states. We have constructed U#16-1 and installed in the PF ring in March 2008. The operation of U#16-1 for the user experiments has been started successfully since April 2008. The construction of the second undulator U#16-2 is underway. U#16-2 will be installed in the PF ring at this summer. We report the result of the magnetic field adjustment of the U#16-2.

• R. Kinjo, M. A. Bakr, Y.W. Choi, T. Kii, K. Masuda, K. Nagasaki, H. Ohgaki, T. Sonobe, M. Takasaki, K. Yoshida
  Kyoto IAE, Kyoto

Aiming at realizing a short period undulator with strong magnetic field, we have proposed a Bulk HTSC (high temperature superconductor) Staggered Array Undulator which consists of bulk high temperature superconductor magnets with a staggered array configuration. The experiment with the prototype undulator at 77 K shows this configuration can be applicable to real undulator. We also estimated the magnetic performance of real device by calculations with a loop current model based on Bean model of superconductor. Although end field termination is required for practical use, traditional methods are not applicable for the bulk HTSCs. We found that the end field termination can be realized by controlling the shape and size of bulk HTSCs at the end section by numerical calculation using the loop current model. In the conference, the calculation and experimental result of end field termination will be presented.

• S. Kashiwagi, G. Isoyama, R. Kato
  ISIR, Osaka
• K. Tsuchiya, S. Yamamoto
  KEK, Ibaraki

The edge-focusing (EF) wiggler has been fabricated to evaluate its performance rigorously with the magnetic field measurement. It is a 5-period planar wiggler with an edge angle of 2° and a period length of 60 mm. The magnetic field is measured using Hall probes at four different wiggler gaps. It is experimentally confirmed that a high field gradient of 1.0 T/m is realized, as designed, along the beam axis. The magnetic field gradient of the EF wiggler is derived as a function of the magnetic gap. The field gradient decreases with increasing magnet gap more slowly than the peak magnetic field does for the present experimental model. An analytic formula for the field gradient of the EF wiggler is derived and it is shown that the slope of the field gradient with the magnet gap can be changed by varying the magnet width of the EF wiggler. We analyzed the relation between the orientation errors of the measurement system and the measured magnetic field or field gradient using a model magnetic field of the EF wiggle. We corrected the measurement magnetic field based on this analysis and evaluated the performance of the EF wiggler.

• T. Kaneyasu, Y. Iwasaki, S. Koda, Y. Takabayashi
  SAGA, Tosu

An APPLE-II type variably polarized undulator was installed in the SAGA-LS storage ring in 2008. Following the installation, we have investigated influence of the undulator on the electron beam. Based on the measurements, we have developed a feedforward correction system to minimize the effects of the undulator. The correction system successfully compensates for closed orbit distortion (COD), betatron tune shift and a weak change in the betatron coupling. The standard deviation of the COD variation relative to the reference orbit and the tune shift are suppressed to less than 4 micron and 0.001, respectively, when the pole gap is changed at a fixed phase. The observed tune shift is interpreted in terms of a second order focusing effect evaluated by RADIA code. The simulated tune shift fairly agrees with the measurements. To minimize the effects on the betatron coupling, a wire-type skew quadrupole magnet mounted on the undulator duct is utilized. The skew field required for the coupling compensation is consistent with those predicted by field integral measurements. The feedforward correction reduces the effect to a relative change in the vertical beamsize of 5%.

• Q.K. Jia
  USTC/NSRL, Hefei, Anhui

The enhancement of arbitrary odd harmonic field is analyzed for pure permanent magnet undulator. The two dimensional analytical formula of the magnetic field is given for a modified Harbch type undulator, in which the magnet blocks have different size. It is shown that the odd harmonic field can be enhanced by optimal the length ratio of the vertical magnetized magnet blocks and the horizontal magnetized magnet blocks, the 3rd harmonic field can exceeded 20% of the fundamental field and 7th harmonic field can exceeded 3 % of the fundamental field for magnet gap-period ratio equal to 0.1.

• M. Gu, R. Chen, Z.H. Chen, G.-Y. Jiang, R. Wang, Q. Yuan
  SINAP, Shanghai

The undulator controller based on Siemens S7-300 PLC is mainly consisted of controlling motion of two stepper motor, monitoring real-time gap position of upstream and downstream through position feedback derived from four linear absolute encoders (LAEs) with 0.1μm resolution, monitoring cooling water's temperature and flux (CWTF), monitoring magnet array temperature (MAT), providing remote access for EPICS via Ethernet, as well as MPS and PPS interlock interface to and from upper-level protection system. In addition, the controller is equipped with considerate motion safety protection tactics. As for the gap position protection, besides mechanical hard stop, software limit, photo-interrupter limit and kill switch are available to achieve it. As for the taper protection, software limit is available to achieve it.

• E.J. Wallén
  MAX-lab, Lund

The MAX IV light source, presently under construction at MAX-lab in Lund, Sweden, will consist of two separate storage rings and a linac-driven short-pulse facility. The two storage rings are operated at different energies, 3 GeV and 1.5 GeV, to provide synchrotron radiation of high brightness over a broad spectral range. The 3 GeV linac serves as a full-energy injector for the storage rings as well as the driver of the short-pulse facility delivering intense x-ray pulses. The paper describes a selection of possible insertion devices to be installed at the MAX IV 3 GeV ring and the expected heat loads produced by the insertion devices.

• D. Schoerling, M. Karppinen, R. Maccaferri
  CERN, Geneva
• A. Ams
  IMFD, Freiberg
• A. Bernhard, P. Peiffer
  KIT, Karlsruhe
• R. Rossmanith
  FZK, Karlsruhe

Two damping rings (e+, e-) are foreseen for the CLIC injection chain. In each damping ring 76 two meter long wigglers will be installed. The short period (40-50 mm), combined with a gap larger than 14 mm and a requested field in the mid-plane BPeak > 2 T requires the usage of superconducting technologies to meet these requirements. To demonstrate the feasibility of this wiggler design a short-model vertical racetrack wiggler (40 mm period; 16 mm gap) was built and successfully tested at CERN. The wiggler carries a current of 730 A and 910 A and reaches a mid-plane peak field of Bpeak = 2 T and Bpeak = 2.5 T at 4.2 K and 1.9 K, respectively. The results show that the wiggler model meets the magnetic requirements of the CLIC damping rings at 1.9 K. The paper will also discuss the improvements we propose to enhance the performance in order to meet the CLIC specifications also at 4.2 K.

• S.D. Chen, T.M. Uen
  NCTU, Hsinchu
• C.-S. Hwang
  NSRRC, Hsinchu

A wiggler with the property of low total radiation power and keeping high photon flux in hard x-ray region, 5-20 keV, which is necessary for the special demand of users, was under investigated for reducing the difficulty of the design of optical components in the beam line and decreasing the load of RF cavity power. Such an insertion devise was called wiggler-like undulator. The spectrum of wiggler-like undulater was investigated with a code, of which the algorithm is based on the compromising between photon flux and radiation power of insertion devices for spectrum optimization. The property of the spectrum of the wiggler-like undulator are discussed herein. Furthermore, the brilliance and the power distribution are somehow also discussed.

• C.M. Wu, C.-S. Hwang, F.-Y. Lin
  NSRRC, Hsinchu

Shimming magnetic field error on each pole in the Elliptically Polarized Undulator (EPU) is a time-consuming work and highly based on experience without scientific systematic methods. Therefore, an auto-field shimming program is developed to save time on pole shimming process. The program is including two major steps to analyze where the poles is defective or imperfect. Step one is to clarify the magnetic pole quality. If its quality is far away to user-defined standards, we change the pole instead of processing to balance them relatively for uniform magnetic field. The magnetic pole quality is based on deltaB/Bavg and deltaI/Iavg(half period of integral) percentage. The second step is to build the effective field and once integral model of pole and permanent magnet calculation. If we shim the defective pole by moving vertically and transversely, it would surge intrinsic change of the deltaB/Bavg and deltaI/Iavg at defective and surrounded poles. Auto-field shimming algorithm would assist us to plan shimming strategies to deal with magnetic poles.

• C. H. Chang, C.-H. Chang, H.-H. Chen, J.C. Huang, M.-H. Huang, C.-S. Hwang, F.-Y. Lin, C.M. Wu
  NSRRC, Hsinchu

An elliptically polarized undulator of length 3.5 m and period length 48 mm (EPU48) is designed to fulfil experiments on spin-polarized PES and inelastic scattering at the Taiwan Photon Source (TPS). EPU48 would be used to produce variously polarized light in the soft X-ray spectral domain 0.4-1.5 keV. To achieve efficient mechanical performance and a high quality of photon source, a new manufacturing method by casting is adopted to fabricate a key component of the carriage of the undulator at National Synchrotron Radiation Research Center (NSRRC). We expect this approach to bestow advantages of decreased assembly error, increased rigidity and highly precise properties. Here we describe details of the design of the magnetic circuit and the mechanical design of the EPU48 based on this new concept of engineering construction.

• Z.W. Huang, D.J. Huang
  NTHU, Hsinchu
• S.D. Chen, M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, Y.T. Yu
  NSRRC, Hsinchu
• S.-Y. Lee
  IUCF, Bloomington, Indiana

A novel gradient damping wiggler (GDW) was developed for the ALPHA storage ring in Indiana University. The GDW will be used to change the momentum compaction factor and the damping partition at ALPHA storage effectively. There is one middle pole and two outer poles that they have gradient field were assembled together on the same girder to be a full set of GDW magnet system. The dipole and gradient field strength of the middle (outer) pole is 0.67 T (-0.67) and 1.273 T/m (1.273 T/m), respectively. The magnet gap of the middle and outer pole is 40 mm and 35.87 mm, respectively, that the three combined function of dipole magnet can be charged by the same power supply. There is a trim coil on the three magnets to adjust the first and second integral field to zero. The good field region of middle pole and outer pole in transverse x-axis (deltaB/B=0.1%) are ±50mm and ±40mm separately. A prototype GDW magnet was fabricated and a Hall probe measurement system was set up to measure the magnet field to verify the magnet design and the magnet construction performance. The field cross-talk and the fringe field are also discussed herein by different methods.

• D. Newton
  The University of Liverpool, Liverpool

An analytic description of the synchrotron radiation from electrons with short-period helical trajectories is given by the Kincaid equation. A new code is under development which generates an analytical description of an arbitrary magnetic field, including non-linear and higher-order multipole (fringe field) components. The magnetic field map of a short-period undulator was modelled, using a 3-d finite element solver, and it's analytical field description has been used to compare the synchrotron radiation output from electrons with a 'realistic' trajectory in terms of the ideal analytic equations. The results demonstrate how small numerical inaccuracies in the particle tracking can lead to large inaccuracies in the calculated synchrotron output. The affects of the higher order field modes are studied which give additional insights into the radiation output from long undulator systems.

• D. Newton
  The University of Liverpool, Liverpool

Recent designs for third generation light sources commonly call for undulator systems with a total length of several hundreds of metres. Calculating the synchrotron output from bunches of charged particles traversing such a system using numerical techniques takes an unfeasibly long time even on modern multi-node computer clusters. Analytical formulae (i.e. the Kincaid Equation) provide a more rapid solution for an idealised system but necessarily fail to produce the non-ideal response which is under investigation. A new code is described which generates an analytic description of an arbitrary magnetic field and uses differential algebra and Lie methods to describe the particle dynamics in terms of series of transfer maps. The synchrotron output can then be calculated using arbitrarily large step size with no loss of accuracy in the trajectory. The code is easily adapted to perform parallel calculations on multi-core machines. Examples of the radiation output from several long magnet systems are described and the performance is assessed.

• E.C.M. Rial, J.C. Schouten
  Diamond, Oxfordshire

Diamond Light Source is currently operating with two multipole superconducting wigglers, one with 49 poles at 3.5 T and another with 49 poles at 4.2 T. The cryogenic arrangement is similar in both cases; each cryostat contains a liquid helium bath cooled by four cryocoolers. The design goal was to allow up to six months continuous operation in the storage ring between refilling the liquid helium bath. However, the helium boil-off is much higher than expected, necessitating much more frequent refills. As well as having a cost implication, this also currently poses a restriction on the operating beam current. In this report we present the results of measurements carried out under various beam conditions to try to understand the reason for the higher boil-off in terms of heat load seen by the cryostat and effective cryocooler performance. We also present our plans for dealing with the problem in the near and longer term.

• E.R. Moog, M. Abliz, K.D. Boerste, T.W. Buffington, D. Capatina, R.J. Dejus, C. Doose, Q.B. Hasse, Y. Ivanyushenkov, M.S. Jaski, M. Kasa, S.H. Kim, R. Kustom, E. Trakhtenberg, I. Vasserman, J.Z. Xu
  ANL, Argonne
• N.A. Mezentsev, V.M. Syrovatin
  BINP SB RAS, Novosibirsk

A number of prototype magnetic structures for a superconducting undulator have been successfully built and tested. The field quality of a test device was measured in a vertical dewar; the phase errors were 7.1 deg. at the maximum design current with no phase shimming. The Advanced Photon Source (APS) specification for overall trajectory was met using the end compensation coils. Several Hall probes have been calibrated at cryogenic temperatures. The design for a cryostat to hold the undulator for installation in the APS storage ring is nearing completion, and a cryogenic measurement facility to measure the magnetic field of the completed undulator is under development.

• G. Rakowsky
  BNL, Upton, Long Island, New York

Various magnet sorting strategies have been used to minimize trajectory and phase errors in undulators, ranging from intuitive pairing of stronger and weaker magnets, to full 3D FEM simulation with actual Helmholtz coil magnet data. We present a simpler approach, first deriving trajectory displacement, kick angle and phase error signatures of each component of magnetization error from a 3D Radia* undulator model. Then, for a given sequence of magnets, the trajectory and phase profiles are computed by cumulatively summing the scaled displacements and phase errors. The rms error is then minimized by swapping magnets according to one's favorite optimization method. A fast, simple magnet swapping algorithm, implemented in Mathematica, is described. 100,000 iterations take only minutes, so dozens of solutions can be compared. This approach was applied recently at NSLS to a short in-vacuum undulator, which required no trajectory or phase shimming. We also obtain trajectory and phase error signatures of some mechanical errors, to guide "virtual shimming" and specifying mechanical tolerances. Finally, multipole signatures of some simple inhomogeneities are modeled.

* O. Chubar, P. Elleaume, J. Chavanne, "A 3D Magnetostatics Computer Code for Insertion Devices", SRI97 Conference August 1997, J. Synchrotron Rad. (1998). 5, 481-484

• T. Tanabe, O.V. Chubar, T.M. Corwin, D.A. Harder, P. He, G. Rakowsky, J. Rank, C.J. Spataro
  BNL, Upton, Long Island, New York

National Synchrotron Light Source-II (NSLS-II) project is now in the construction stage. A new insertion device (ID) magnetic measurement facility (MMF) is being set up at Brookhaven National Laboratory in order to satisfy the stringent requirement on the magnetic field measurement of IDs. ISO-Class7 temperature stabilized clean room is being constructed for this purpose. A state-of-the-art Hall probe bench and integrated field measurement system will be installed therein. IDs in the project baseline scope include six damping wigglers, two elliptically polarizing undulators (EPUs), three 3.0m long in-vacuum undulators (IVUs) and one 1.5m long IVU. Three-pole wigglers with peak field over 1 Tesla will be utilized to accommodate the users of bending magnet radiation at the NSLS. Future plan includes: 1) an in-vacuum magnetic measurement system, 2) use of PrFeB magnet for improved cryo undulator, 3) development of advanced optimization program for sorting and shimming of IDs, 4) development of a closed loop He gas refrigerator, 5) switchable quasi-periodic EPU. Design features of the baseline devices, IDMMF and the future plans for NSLS-II ID activities are described.

• C. Liu
  CASA, newport news
• G.A. Krafft
  JLAB, Newport News, Virginia
• G.M. Wang
  BNL, Upton, Long Island, New York

The possibility of producing sub-ps x-ray by putting undulator in CEBAF machine will be discussed. The performance of undulator radiation at CEBAF will be calculated and compared with storage ring light source.

• L.X. Yan, Q. Du, Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C. Liao, C.-X. Tang
  TUB, Beijing

Ultrashort relativistic electron beam can be applied to produce high power coherent THz radiation by mechanisms such as FEL, CSR, CTR et al. The THz modulated electron beams, or THz-repetition-rate ultrashort electron bunch trains exhibit further enhancement of coherent THz radiation. This article will report the experimental results on the ultrashort electron bunch train production by copper based photocathode RF gun via direct UV laser pulse stacking using birefringent α-BBO crystal serials at our laboratory. The temporal profile of the electron beam was measured by deflecting cavity. Space charge effect downstream the photocathode is simulated. This shaping method of laser pulse by α-BBO crystals can also be applied to form quasi flattop UV laser pulse for reducing the initial emittance of the electron beam from the photocathode RF gun.

• C.P. Hauri, B. Beutner, H.-H. Braun, R. Ganter, C.H. Gough, R. Ischebeck, F. Le Pimpec, M. Paraliev, M. Pedrozzi, C. Ruchert, T. Schietinger, B. Steffen, A. Trisorio, C. Vicario
  PSI, Villigen

In the framework of the SwissFEL activities at PSI we developed a powerful UV laser system delivering wavelength-tunable pulses at a central wavelength varying from 260 to 283 nm. The laser system based on a ultra-stable frequency-trippled Ti:sapphire amplifier delivers mJ pulse energy within a duration of 1-10 ps with 1.5 nm spectral width. Temporal flattop pulses are achieved by direct UV shaping with a UV Dazzler and a prism-based stretcher. The system is used to explore thermal emittance and quantum efficiency dependence on photon energy from metallic photo-cathode (Cu and Mo). With pepperpot techniques we have measured the predicted theoretical limit for thermal emittance (0.4 mm.mrad / mm rms laser spot size at 283 nm and 0.6 mm.mrad / mm at 263 nm) for metallic photocathodes.

• R. Tikhoplav, A.Y. Murokh
  RadiaBeam, Santa Monica
• I. Jovanovic
  Purdue University, West Lafayette, Indiana

Of particular interest to X-ray FEL light source facilities is Enhanced Self-Amplified Spontaneous Emission (ESASE) technique. Such a technique requires an ultrafast (20-50 fs) high peak power, high repetition rate reliable laser systems working in the mid-IR range of spectrum (2μm or more). The approach of this proposed work is to design a novel Ultrafast Mid-IR Laser System based on optical parametric chirped-pulse amplification (OPCPA). OPCPA is a technique ideally suited for production of ultrashort laser pulses at the center wavelength of 2 μm. Some of the key features of OPCPA are the wavelength agility, broad spectral bandwidth and negligible thermal load.

• E. Takeshita, T. Furukawa, T. Inaniwa, Y. Iwata, K. Noda, S. Sato, T. Shirai
  NIRS, Chiba-shi

The development of the screen monitor system (SCN) at the Heavy Ion Medical Accelerator in Chiba (HIMAC) comprises the surveillance of the carbon beam. In the three-dimensional scanning system for the carbon therapy, the beam qualities, i.e., position, size and intensity of the beam, play a significant role for the patient's treatment. Therefore, we designed a semi-nondestructive monitoring system located on the the high-energy beam transport line to monitor the beam qualities by using a thin fluorescent screen and a high-speed charge-coupled device. The beam position and profile were obtained from the light emitting distribution of the screen. The SCN was checked on the prototype scanning system at HIMAC and succeeded to monitor the beam real-time in steps of about 10 msec, corresponding to a 100 Hz sampling rate. The developments steps will focus toward a operation at HIMAC's new therapy facility extension, recently. In the conference, we would like to report on details of the automatic beam tuning before starting the treatment and the interlock system during therapy using the SCN.

• G. Isoyama, M. Fujimoto, K. Furuhashi, S. Kashiwagi, R. Kato, M. Morio, J. Shen, S. Suemine, N. Sugimoto, Y. Terasawa
  ISIR, Osaka
• S. Hirata
  Hiroshima University, Faculty of Science, Higashi-Hirosima

The 40 MeV L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University is extensively used for various applications on advanced beam sciences including radiation chemistry by means of pulse radiolysis and development of the free electron laser in the THz region. It was constructed in 1975-78 and has been remodeled sometimes for improving its performance. The most recent one was made in 2002-2004 for higher operational stability and reproducibility, resulting in significant advances in the studies. We will report the present status of the linac and results of its performance evaluation.

• P. Chu, R.H. Iverson, P. Krejcik, D. Rogind, G.R. White, M. Woodley
  SLAC, Menlo Park, California

Linac Energy Management (LEM) is a control system program which calculates, and optionally implements, magnet setpoint settings (BDESs) following a change in Energy (such as a change in the number, phase, and amplitude of active klystrons). The change is made relative to those magnets' existing BDES setpoints by a factor encoding the change in energy. LEM is necessary because changes in the number, phase, and amplitude of the active klystrons (the so-called "Klystron complement") change the beam's rigidity, and therefore, to maintain constant optics, one has to change focusing gradients and bend fields. This paper describes the basic process and some of the implementation lessons learned for LEM at the LCLS.

• L. Corner, L.J. Nevay
  OXFORDphysics, Oxford, Oxon
• L. Corner, R. Walczak
  JAI, Oxford

We present the results of the development of a high power fibre laser system for the laserwire project to measure very low emittance electron beams. We use the output of a commercial 1uJ, 6.49MHz laser system and amplify it in rod type photonic crystal fibre. This is a novel form of optical fibre which has a large core diameter (70um) but still supports only a single Gaussian spatial mode, essential for focusing the beam to the smallest spot size and achieving the highest resolution. We amplify the seed pulses in a burst mode suitable for use in a linear accelerator, which has the advantage of decreasing the pump power required and thus reducing the running cost and heat loading of the laser system. The amplified pulses have energies of ~ 100uJ in the near infrared and excellent beam quality, as specified in the original design, and are frequency converted to the green to give sub-micron spatial resolution.

• C. Kondo, K. Shirasawa
  JASRI/SPring-8, Hyogo-ken
• T. Inagaki, T. Sakurai, T. Shintake
  RIKEN/SPring-8, Hyogo

Low electro-magnetic noise interference (EMI) is required to the klystron modulator power supply for XFEL/SPring-8 project in order to realize the highly stable beam operation with aid of various feedback loops using high-performance beam monitors. The dominant noise source is the thyratron switching noise, associated with its rapid voltage swing of 50 kV maximum. To suppress the noise leakage, special care was taken to the enclosure design of klystron modulator, i.e., using thick steel plates a monocoque enclosure was fabricated, in which all of the high power circuits was installed. The rapid image current flows on the inner surface, thus EMI was minimized. A special co-axial feed-though was developed for filtering the conducted noise on power line for thyratron and klystron heaters. In this presentation, we will report the details of the devices and the results of the noise suppression.

• T. Ozaki, A. Akiyama, K. Harada, T. Kasuga, Y. Kobayashi, T. Miyajima, S. Nagahashi, T.T. Nakamura, M. Ono, T. Sueno
  KEK, Ibaraki

At PF-AR, a bending magnet power supply was updated in 2007. The converter works in the 3 pulsed PWM. A trouble caused by higher harmonics above 40th had occurred. We manufactured filters and installed in 6.6kV ac lines in 2008. Furthermore, a QF magnet power supply was updated in 2009. This paper reports on the update of PF-AR main magnet power supplies.

• H. Sato, t.s. Shintomi
  KEK, Ibaraki
• T. Ise, Y. Miura
  Osaka University, Graduate School of Engineering, Osaka
• S. Nomura, R. Shimada
  RLNR, Tokyo

Magnets of the synchrotron accelerator which extracts the accelerated beams are excited by pulse operation power supply, and then the load fluctuation should be a severe problem. An energy storage system, such as SMES, fly-wheel generator so far, will be required for compensating the pulse electric power, and reducing the disturbances of the connected power line. The system is also expected to protect the instantaneous voltage drop and contributes the reliability of the storage ring. Present status of R & D and the features for the energy storage systems are discussed. The application of the energy storage systems to synchrotrons for the medical use is described. The compensation of the typical pulse electric power of the synchrotron for the cancer therapy is studied.

• H. Someya, S. Igarashi
  KEK, Ibaraki
• S. Nakamura
  J-PARC, KEK & JAEA, Ibaraki-ken

The power supply current ripple of the quadrupole magnets of the J-PARC main ring has been measured to be the order of 10^-4. The magnetic field of the quadrupole magnets has been measured and the ripple frequency distribution of each magnet was observed to be depending on where the magnet is in the magnet chain. A transmission line model for the cable and magnets was able to explain the distribution. The field ripple made by the common mode current ripple was reduced by changing the magnet cabling to be symmetrical with respect to the N and S poles of the quadrupole magnets. The common mode ripple was drastically reduced. The normal mode ripple of 600, 1200 and 1800 Hz however remained. The field ripple was further reduced using resistors those are connected in parallel to the magnet coils and bypass the current ripple. It was effective to the higher frequency ripple of 1200 and 1800 Hz and the effect was in a good agreement with an electric circuit simulation program LTspice.

• Y. Watanabe
  JAEA, Ibaraki-ken

In J-PARC RCS, horizontal closed orbit distortion (COD) which is ±2 or 3mm in amplitude was observed all over the ring. Main component of the horizontal COD is 1kHz, phase variation period about 140 seconds. This paper demonstrates phase variation of the 1kHz horizontal COD caused by switching ripple from dipole magnet power supply. To suppress the phase variation of the horizontal COD, switching timing of the dipole magnet power supply was synchronized J-PARC timing system.

• H. Toki, K. Sato
  RCNP, Osaka

The ordinary electric circuits produce and receive electromagnetic noise. The noise is a problem for stable operation of synchrotron accelerators. We do not know the origin of the noise generation due to the lack of electric circuit theory, which takes into account the noise sources. The proper treatment of electric circuit together with noise requires a proper knowledge of multiconductor transmission-line theory. We have developed a new multiconductor transmission-line theory in which we are able to describe the performance of multiconductor transmission-line system*. In this theory, it is essential to use the coefficients of potential instead of capacities and the introduction of the normal and common modes. After understanding the multiconductor transmission-line theory, we propose the introduction of the middle line (three lines) and symmetric arrangements of electric loads**. The use of this concept made the J-PARC MR successful in operation.

* H. Toki and K. Sato, J. Phys. Soc. Jpn 78 (2009) 094201.
** K. Sato and H. Toki, Nucl. Inst. Methods A565 (2006) 351.

• S.-C. Kim, K.R. Kim, S.H. Nam, C.D. Park, Y.G. Son, C.W. Sung
  PAL, Pohang, Kyungbuk

Lattice of the Storage Ring (SR) is changed from TDB to DBA, and beam energy is enhanced from 2.5 GeV to 3.0 GeV at the Pohang Light Source upgrade (PLS-II). Therefore all magnet specification and number have to change compare with exist PLS SR. At the PLS-II, Magnet Power Supplies (MPS) must be re-designed according to magnet specification of the PLS-II. Newly development MPSs are adopted switching type power conversion technology. High current unipolar MPSs are parallel operation type of unit module buck type power supply, and low current bipolar MPSs are H-bridge type. All MPSs are performed ± 10 ppm output current stability and adopted full digital controller. In this paper, we report on the development and characteristics of the MPS for PLS-II SR.

• M. Pont, D. Alloza, R. Petrocelli, D. Yepez
  CELLS-ALBA Synchrotron, Cerdanyola del Vallès
• R. Camell, G. Gross, M. Teixido
  CITCEA-UPC, Barcelona

ALBA is a 3 GeV third generation synchrotron light source under construction in Spain. The design and performance of the ALBA Storage Ring Power Converters will be described. A total of 122 power converters are required: 1 for the dipoles (all connected in series), 112 for the quadrupoles (each magnets with its own power supply) and 9 for the sextupoles (each family connected in series). All converters are switched mode with full digital regulation and a common control interface. The paper will describe the performance of the power converters and compare it with the design specifications.

• M. Pont, D. Alloza, R. Petrocelli, D. Yepez
  CELLS-ALBA Synchrotron, Cerdanyola del Vallès
• R. Camell, G. Gross, M. Teixido
  CITCEA-UPC, Barcelona

ALBA is a 3 GeV third generation synchrotron light source under construction in Spain. The injection system is composed of a 100 MeV Linac as pre-injector followed by a full energy booster synchrotron. The booster requires AC power converters operating at 3.125 Hz with a sinusoidal current waveform. All converters are switched mode with full digital regulation and a common control interface. The design specifications have been demonstrated and early tests on the Booster commissioning with beam will be presented

• M. Pont
  CELLS-ALBA Synchrotron, Cerdanyola del Vallès

ALBA is a 3 GeV third generation synchrotron light source under construction in Spain. The injection system is composed of a 100 MeV Linac as pre-injector followed by a full energy booster synchrotron which shares the same tunnel as the storage ring. With a circumference of 249.6 m and a magnetic lattice based on combined magnets an emittance of 9 nm.rad has been predicted. At present time we are in an intensive sub-system commissioning testing with the aim to start the commissioning with beam early in January 2010.

• H. Thiesen, M.C. Bastos, G. Hudson, Q. King, V. Montabonnet, D. Nisbet, S.T. Page
  CERN, Geneva

The LHC was restarted on the 20th of November 2009 after 14 months of shutdown. The machine is composed of 8 powering sectors, each containing a main dipole circuit and two main quadrupole circuits. Each of these main circuits is entirely independent. To operate the LHC, the magnetic fields in the main magnets must be controlled with unprecedented accuracy. Indeed, the current in each power converter must be controlled with an accuracy of a few ppm (parts per million of nominal current) and the currents must be perfectly synchronised between sectors. To achieve the performance required of the LHC power converters, many challenges have been resolved. These include: measuring the power converter currents with an extreme absolute precision, control of these currents without tracking error or overshoot, perfect synchronisation of the current references sent to the power converters of the 24 main circuits. This paper details how these various problems have been resolved to obtain the performance required. Many experimental results are included, in particular the results of the tracking tests performed with the main circuits of the LHC.

• M. Emmenegger, H. Jaeckle, R. Künzi, S. Richner
  PSI, Villigen

In accelerator applications, high precision high speed power supplies (PSs) for magnets are needed to guarantee the high beam quality. These PSs are the main purpose of the presented second generation of a Digital Power Electronic Control System (DPC) which has been designed and successfully applied at the Paul Scherrer Institute PSI. The main components of the DPC are the controller board (DPC_CC) and the high precision analogue to digital converter board (DPC_AD). Compared to the first generation the properties such as precision, acquisition rate, processing power and functionality have been improved considerably. This allows faster control cycles and/or more complex control algorithms. The controller board now features 12 standard precision (16 bit) ADC channels and allows the simultaneous control of multiple power supplies. High precision requirements are met by adding the DPC_AD to the system. In conclusion, the modular and flexible design allows well-matched solutions for the typically heterogeneous accelerator power supplies.

• Y.-H. Liu, J.-C. Chang, C.-Y. Liu
  NSRRC, Hsinchu

The purpose of this paper is to estimate the conductive Electromagnetic Interference (EMI) from magnet power supply in NSRRC. A LISN system was conducted to measure the EMI spectrum of power supply. The different frequency range of conductive EMI was measured. For the future TPS(Taiwan Photon Source) power supply design, the EMI signals must be lower than TLS kicker. Therefore reducing and eliminating the interference of electromagnetic waves will be a very important issue. A filter and shielding method were used to test the effects of reducing EMI. The EMI prevention scheme will be used in the future.

• K.-B. Liu, K.T. Hsu, Y.D. Li, B.S. Wang
  NSRRC, Hsinchu
• J.C. Hsu
  CMS/ITRI, Hsinchu

Based on the requirement of beam stability for the third-generation synchrotron radiation light source is more stringent, lower ripple and higher bandwidth of output current of corrector magnet power converters should be developed to implement the closed orbit correction of Taiwan Photo Source (TPS). The ±10A/±50V corrector magnet power converter uses a full bridge configuration, the switching frequency of power MOSFET is 40 kHz, in that each bridge leg has its own independent PWM controller and the output current bandwidth is 1 kHz when connected with the corrector magnet load. Using a DCCT as the current feedback component the output current ripple of this converter could be lower than 5 ppm. In this paper, we will describe the hardware structure and control method of the corrector magnet power converter and the test results will be demonstrated.

• C.-Y. Liu, Y.D. Li
  NSRRC, Hsinchu

We design and implement a power convert to supply dc power bus for the MCOR30 correction supply. The dc power supply's characteristics were variable frequency at heavy and medium/light load. These characteristics matched with the correction supply working requirement. The dc power bus has a relaxation oscillator generating a symmetrical triangular waveform, which MOSFET's switching is locked to. The frequency of this waveform is related to a current that will be modulated by feedback circuitry. As a result, the tank circuit driven by half-bridge will be stimulated at a frequency dictated by the feedback loop to keep the output voltage regulated, thus exploiting its frequency-dependent transfer characteristics. The high performance characteristics of the resonant dc power bus are illustrated in this paper.

• K.-B. Liu, K.T. Hsu, Y.D. Li, B.S. Wang
  NSRRC, Hsinchu

The Taiwan Photon Source (TPS), a third-generation synchrotron radiation light source, should be installed with 1032 sets of magnet power supplies for the storage ring and 152 sets for the injector. All of the power supplies are preferred in PWM switched mode with IGBT or MOSFET. A high precision DC power supply for 48 dipoles of the storage ring; there are 240 quadrupole magnets and 168 sextupole magnets in storage ring, the main winding of quadrupole and 168 sextupole magnets are powered by individual power supplies. In the booster ring, one set of dynamic power supply for the dipole magnets and four sets for quadrupole magnets run at the biased 3Hz quasi sinusoidal wave. There are several hundred corrector (fast and slow) magnets and skew quadrupole magnets in storage ring and injector are powered by the same bipolar power converters.

• B.S. Wang, K.T. Hsu, Y.D. Li, K.-B. Lin, K.-B. Liu
  NSRRC, Hsinchu

This paper presents an implementation of a precision corrector magnet power converter using the digitally controlled pulse width modulation method. The output current precision of this ±10A/±50V corrector magnet power converter is within ±10ppm. The digital control circuit of the power converter is implemented with using a high speed ADS8382 18-bits analog-to-digital converter and a TMS320F28335 digital signal processor. The converter uses a full bridge configuration, the switching frequency of power MOSFET is 40 kHz and the control resolution is 17-bits. Using a DCCT as the current feedback component the output current ripple of this converter could be lower than 5 ppm that is beyond the requirement of TLS corrector power converter and suitable to be used in TPS.

• G. Feng, B. Deriy, T. Fors, J. Wang
  ANL, Argonne

The DC/DC converters in the Advanced Photon Source storage ring are more than 15 years old, and an upgrade is underway to resolve the aging and obsolescence issues. In the upgrade, an 18-bit resolution for current regulation is desired. This paper describes a digital control system to achieve this goal. The system uses a serializer chip, TI TLK2541, combined with a ∑-Δ modulator to realize a 21-bit digital pulse width modulation (DPWM). Analog and digital filters are implemented to block the ripple currents and to reduce the EMI noises. Deployed with filter circuits, a digital compensator has been designed to meet the requirements of output current regulation. Furthermore, a voltage feed forward is employed to compensate for input bus voltage variations. A prototype digital controller using a field-programmable-gate-array development board has been developed. The resolution of the current regulation, and the effect of noises into the digital controlled power converter system have been tested and analyzed.

• G. Busatto, C. Abbate, F. Iannuzzo, C.E. Pagliarone
  University of Cassino, Cassino
• F. Bedeschi, G.M. Piacentino
  INFN-Pisa, Pisa

The possible issues related to the use of last-generations Insulated Gate Bipolar Transistors (IGBTs) switches into a Marx-topology klystron modulator are discussed. Experimental results obtained from two cells Marx prototypes using two different solutions, including single device and series connected devices both hard-switched, are presented. The use of single high voltage device per cell allowed us to obtain lower on-state voltage drop but much slower switching times. On the other side the series connection of lower voltage IGBTs results in much faster commutations and lower devices costs accompanied by a larger on state voltage drop.

• T. Shintake, T. Inagaki, C. Kondo, T. Sakurai, K. Shirasawa
  RIKEN/SPring-8, Hyogo

XFEL/SPring-8 will use 72 line type modulator pulse-power supply for 66 C-band klystrons, 4 S-band, one L-band and pulsed 500 kV electron gun. In order to make the size smaller to fit the space available in the high gradient C-band accelerator, we have developed all in one box design of modulator. Using metal monocok design, filled with oil, it becomes possible to fit all circuitry: PFN, thyratron, pulse transformer, klyston socket, and protection circuit into a metal box of W 1m x L 1.7m x H 1m, which provides strong support for massive klystron and solenoide with lead shield and functions as superior EM shiled. We developed high precission HV charger for PFN, which has stability better than 100 ppm.pp. Modulator and PFN chargers are under mass prodution.

• M. Akemoto, S. Fukuda, H. Honma, H. Nakajima, T. Shidara
  KEK, Ibaraki

This paper describes a long-pulse 1.3 GHz klystron modulator that was recently developed for the Superconducting RF Test Facility (STF) at High Energy Accelerator Research Organization (KEK). The modulators is a direct-switched-type design with a 1:15 step-up transformer and a bouncer circuit to compensate for the output pulse droop within ±0.5%; it can drive a klystron with up to 10 MW peak power, 1.5 ms rf pulse width, and up to 5 pps repetition rate. The main features of this modulator are the use of four 50 kW switching power supplies in parallel to charge the storage capacitors to 10 kV, self-healing-type capacitor to realize a compact storage capacitor bank, and a highly reliable IGBT switch which enables elimination of a crowbar circuit. Design considerations and its performance are presented. An IEGT (Injection Enhanced Gate Transistor) switch, composed of six series devices with a rating of 4.5 kV and 2100 A-DC, has been also developed and tested for R&D to realize a compact modulator.

• T. Takayanagi, M. Kinsho, P.K. Saha, T. Togashi, T. Ueno, M. Watanabe, Y. Yamazaki, M. Yoshimoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• H. Fujimori
  J-PARC, KEK & JAEA, Ibaraki-ken
• Y. Irie
  KEK, Ibaraki

At the J-PARC 3-GeV injection, the injection painting area is designed to be different for supplying the MLF (Material Life Science Facility) and MR (50GeV Main Ring) beams. Along with the injection system in the ring, pulsed switching magnets which are installed in the injection beam-line should also have a function to control the beam orbit at 25Hz. The deflection angle ranges from 3 to 38 mrad to meet the user operation as well as the beam physics run.

• M. Watanabe, J. Kamiya, K. Suganuma, T. Takayanagi, N. Tani, T. Togashi, T. Ueno, Y. Watanabe
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

3 GeV rapid cycling synchrotron (RCS) of J-PARC accelerates proton beams from the 181 MeV up to 3 GeV. The RCS injects the beam to the Main Ring and transports it to the muon production target and neutron production target in the Materials and Life Science Experimental Hall. Proton beams in the RCS are fast extracted by kicker magnets at the repetition rate of 25 Hz. The rise time of the magnetic field is approximately 260 ns due to the propagation time through the coaxial cable and the kicker magnet itself. The flat-top length of it is required to 840 ns in order to extract two beam bunches. Pulse forming lines (PFL) and thyratrons are used to make the rise time and the flat-top, at the maximum charging voltage of 80 kV. Two thyratrons, which is a CX1193C made by e2V Ltd., are used for a power supply. 16 thyratrons are used in the eight power supplies of the kicker system. Since thyratrons are gaseous discharge switching devices, they often make misfire or self-breakdown in several hours. In this paper, present status of operation and voltage adjustment method of the reservoir and cathode heater power supply of the thyratrons in the kicker system are described.

• I. Rodríguez, F. Toral
  CIEMAT, Madrid
• M.J. Barnes, T. Fowler, G. Ravida
  CERN, Geneva

The goal of the present CLIC Test Facility (CTF3) is to demonstrate the technical feasibility of specific key issues of the CLIC scheme. The extracted drive beam from the combiner ring (CR), a pulse of 35 A magnitude and 140 ns duration, is sent to the new CLic EXperimental area (CLEX). A Tail Clipper (TC) kicker is required, in the CR to CLEX transfer line, to allow the duration of the beam pulse to be adjusted: the unwanted bunches are kicked into a collimator. The TC must have a fast field rise-time, of not more than 5 ns, in order to minimize uncontrolled beam loss. Striplines are used for the TC: to establish the required fields, the applied pulse wave front must fully propagate along the striplines. To reduce the wave front propagation time, the overall length of the stripline assembly is sub-divided into 4 sections. The TC has been designed with the aid of detailed numerical modelling: the stripline cross-section and coaxial-to-stripline transitions were carefully optimized using a 3D code. The results of simulations and the measured behaviour of the striplines are presented; in addition measured current pulses are shown.

• M.J. Barnes, L. Ducimetière, B. Goddard, C. Heßler, V. Mertens, J.A. Uythoven
  CERN, Geneva

Proton and ion beams will be injected into LHC at 450 GeV by two kicker magnet systems, producing magnetic field pulses of up to 7.8 μs flat top duration with rise and fall times of not more than 900 ns and 3 μs, respectively. Both systems are composed of four traveling wave kicker magnets, powered by pulse forming networks. One of the stringent design requirements of these systems is a field flat top and post pulse ripple of less than ±0.5 %. A carefully matched high bandwidth system is required to obtain the stringent pulse response. Screen conductors are placed in the aperture of the kicker magnet to provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against Wake fields: these conductors affect the field pulse response. Recent injection tests provided the opportunity to directly measure the shape of the kick field pulse with high accuracy using a pilot beam. This paper details the measurements and compares the results with predictions and laboratory measurements.

• M.J. Barnes, L. Ducimetière, J.A. Uythoven
  CERN, Geneva

The Compact Linear Collider (CLIC) study is exploring the scheme for an electron-positron collider with high luminosity (10³⁴ - 10³⁵ cm²/s) and a nominal centre-of-mass energy of 3 TeV: CLIC would complement LHC physics in the multi-TeV range. The CLIC design relies on the presence of Pre-Damping Rings (PDR) and Damping Rings (DR) to achieve the very low emittance, through synchrotron radiation, needed for the luminosity requirements of CLIC. In order to limit the beam emittance blow-up due to oscillations the combined flat-top ripple and droop of the field pulse, for the DR extraction kickers, must be less than 0.015%. In addition, the allowed beam coupling impedance for the kicker systems is also very low: a few Ohms longitudinally and a few MΩ/m transversally. This paper discusses initial ideas for achieving the extremely demanding requirements for the PDR and DR kickers.

• F. Caspers, M. Betz, A. Grudiev
  CERN, Geneva
• H. Sapotta
  University of Applied Sciences Karlsruhe, Karlsruhe

In many particle accelerators considerable amounts of RF power reaching the megawatt level are converted into heat in dummy loads. After an overview of RF power in the range 200 MHz to 1 GHz dissipated at CERN we discuss several developments that had come up in the past using vacuum tube technology for RF-DC conversion. Amongst those the developments the cyclotron wave converter CWC appears most suitable. With the availability of powerful Schottky diodes the solid state converter aspect has to be addressed as well. One of the biggest problems of Schottky diode based structures is the junction capacity. GaAs and GaN Schottky diodes show a significant reduction of this junction capacity as compared to silicon. Small rectenna type converter units which had been already developed for microwave powered helicopters can be used in waveguides or with coaxial power dividers.

• L. Sermeus, M.J. Barnes, T. Fowler
  CERN, Geneva

A five-turn continuous extraction is currently used to transfer the proton beam from the CERN PS to the SPS. This extraction uses an electrostatic septum to cut the filament beam into five slices, causing losses of about 15 %. These losses would be an even greater drawback when the beam intensity is further increased for the CERN Neutrinos to Gran Sasso facility. To overcome this, a Multi-Turn Extraction (MTE) has been implemented, in which the beam is separated, prior to extraction, into a central beam core and four islands. Each beamlet is extracted using a set of kickers and a magnetic septum. For the kickers two new pulse generators have been built, each containing a lumped element Pulse Forming Network (PFN) of 12.5 Ohms, 80 kV and 10.5 μs. For cost reasons existing 15 Ω transmission line kicker magnets are reused. The PFN characteristic impedance deliberately mismatches that of the magnets to allow a higher maximum kick. The PFN design has been optimised such that undesirable side-effects of the impedance mismatch on kick rise-time and flat-top remain within acceptable limits. The kicker systems put in place for the current first phase of MTE are presented.

• V. Senaj, L. Ducimetière, E. Vossenberg
  CERN, Geneva

The vertical beam dump system of the CERN Super Proton Synchrotron (SPS) uses two matched magnets with an impedance of 2 Ω and combined kick strength of 1.152 Tm at 60 kV supply voltage. For historical reasons the two magnets are powered from three 3 Ω pulse forming networks (PFN) through three thyratron-ignitron switches. Recently flashovers were observed at the entry of one of the magnets, which lead, because of the electrical coupling between the kickers, to a simultaneous breakdown of the pulse in both magnets. To improve the reliability an upgrade of the system was started. In a first step the radii of surfaces at the entry of the weak magnet were increased, and the PFN voltage was reduced by 4 %; the kick strength could be preserved by reducing the magnet termination resistance by 10 %. The PFNs were protected against negative voltage reflections and their last cells were optimised. In a second step the two magnets will be electrically separated and powered individually by new 2 Ω PFNs with semiconductor switches.

• K.L. Tsai, C.-T. Chen, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, K.-B. Liu
  NSRRC, Hsinchu
• Y.-C. Liu
  National Tsing-Hua University, Hsinchu

A test unit of a pulse-forming-network (PFN) kicker power supply has been designed and fabricated for Taiwan Photon Source (TPS) beam injection/extraction of the booster ring. In order to fulfill the requirements, the performance of the designed unit has been bench tested and the results are examined for evaluation purpose. The pulse-to-pulse stability and the flattop specifications are specified according to the beam injection/extraction requirements. Effort has been made to enhance the rise/fall time of the delivered pulse current. The engineering evaluation and its possible application for beam diagnostics purpose are briefly discussed.

• M.A. Clarke-Gayther
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

A description is given of the development of slow-wave chopper structures for the 3.0 MeV, 60 mA, H‾ MEBT on the RAL Front-End Test Stand (FETS) [1]. 'Helical' and 'Planar' electrode designs [2] have been developed by simulating their high frequency (HF) electromagnetic properties in a commercial 3D code [3], and the manufacture of prototypes has helped to validate the predictive accuracy of the design code, and the selection of suitable machine-able ceramics and alloys of copper and aluminium. A description is also given of a novel abrasive brushing process that enables fine tuning of stripline characteristic impedance by facilitating control of stripline edge radius. The transmission line properties of the previously described 'Helical' test assembly [4] are compared with those of the recently completed 'Planar' test assembly. Finally, the development status of a related prototype high voltage pulse generator is presented.

• M.K. Kempkes, M.P.J. Gaudreau, R.A. Phillips, D. Robinson, K. Schrock
  Diversified Technologies, Inc., Bedford, Massachusetts

Diversified Technologies, Inc. (DTI) recently delivered a 500 kW CW, 33 kV solid-state test stand for the evaluation and conditioning of high power tetrodes employed in accelerator and radar systems. The test system consists of DTI-manufactured and commercially-sourced power supplies, a DTI high voltage opening switch, and DTI controls. Combining an opening switch and fast responding power supplies allows the hi-potting and high power burn-in to be consolidated in one test stand. Faulty tubes, which would not operate in a crowbar-equipped modulator, and could not be processed to health on a high potter, can be revived to health with this fast opening switch circuitry. By limiting peak fault current and follow-on-current, the total energy in an arc event is greatly minimized, reducing damage inside the tube. If greater energy (or action) is required for initial tube processing, additional load capacitance downstream of the switch can be added into the circuit for 'spot knocking' purposes. This test stand is capable of operation in pulsed mode as well as CW. This paper will address the design and construction of the test stand and discuss results since its installation.

• M.K. Kempkes, R. Ciprian, M.P.J. Gaudreau, T.H. Hawkey, K. Schrock
  Diversified Technologies, Inc., Bedford, Massachusetts

Diversified Technologies, Inc.(DTI) has delivered a fully solid state Klystron Power Supply for the ISIS Front End Test Stand to Rutherford Appleton Laboratory in the UK. The new pulsed power supply drives a Toshiba E3740A klystron in preparation for construction of a system to demonstrate high quality intense chopped beams. DTI's system represents a significant advance in solid-state high power accelerator technology based upon a hard switch developed for the US Department of Energy (DOE) to meet similar requirements for the International Linear Collider(ILC). The system includes two 220 kW switching power supplies, a 110 kV solid state hard switch pulse modulator, mod anode and filament power supplies, klystron fault protection, and interfaces to the ISIS controls. This paper will address the design and construction of the KPS system, as well as test results from the installation at RAL in May 2009.

• G.C. Pappas
  LBNL, Berkeley, California

The Next Generation Light Source (NGLS) at Lawrence Berkeley Laboratory is a 2.4 GeV linear accelerator with up to ten FELs. Each of the FELs require a fast kicker, with the exception of the final one which can use a normal bend magnet. The requirements for the kickers are to deflect the linac beam by an angle of 3 mrad with a magnetic length of 2 m, and an aperture size of 17 by 17 mm. A strip line magnet with an impedance of 50 Ohms being feed from the opposite direction as the beam has been selected for prototyping. The modulator requirements to drive such a magnet are ±15 kV and ±300 A, with rise and fall times of 5 ns and a flat top of 10 ns. The pulse to pulse stability must be better than 0.01% of the peak value. The design of the modulator is an inductive adder with 20 cells, each driven by 12 power MOSFETs. This paper describes details of the design as well as present preliminary test data.

• Y.-J. Chen, D.T. Blackfield, S.D. Nelson, B. R. Poole
  LLNL, Livermore, California

Vacuum insulators composed of alternating layers of metal and dielectric, known as high-gradient insulators (HGIs), have been shown to withstand higher electric fields than conventional insulators. Generally, vacuum insulator failure is due to surface flashover, initiated by electrons emitted from the triple junction. These electrons strike the insulator surface and produce secondary electrons, which also strike the insulator surface to create more secondary electrons and lead to avalanche. Magnetic field from the external sources, the high-current electron beam, the conduction current in the transmission line or the displacement current in the insulator can deflect primary and secondary electrons' trajectories either toward to or away from the insulator surface, and hence affect the performance of the high-voltage vacuum insulator. The displacement current effects are particularly interesting for short pulse applications. This paper presents the displacement current effects with various short applied voltage pulses on performance of high-gradient insulators. Optimal HGI configurations will also be discussed.

• M.N. Nguyen, C. Burkhart, K.J.P. Macken, J.J. Olsen
  SLAC, Menlo Park, California

SLAC National Accelerator Laboratory has built and is currently operating a first generation prototype Marx klystron modulator to meet ILC specifications. Under development is a second generation prototype, aimed at improving overall performance, serviceability, and manufacturability as compared to its predecessor. It is designed around 32 cells, each operating at 3.75 kV and correcting for its own capacitor droop. Due to the uniqueness of this application, high voltage gate drivers needed to be developed for the main 6.5 kV and droop correction 1.7 kV IGBTs. The gate driver provides vital functions such as protection of the IGBT from over-voltage and over-current, detection of gate-emitter open and short circuit conditions, and monitoring of IGBT degradation (based on collector-emitter saturation voltage). Gate drive control, diagnostic processing capabilities, and communication are digitally implemented using an FPGA. This paper details the design of the gate driver circuitry, component selection, and construction layout. In addition, experimental results are included to illustrate the effectiveness of the protection circuit.