| Paper | Title | Page |
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| TUPMA001 | New Connection Cryostat to Insert FP420 Proton Tagging Detector in the LHC Ring | 103 |
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| FP420 is a R&D project to assess the feasibility of installing proton tagging detectors in the region 420m from the interaction points at the LHC. They would function as new sub-detectors at ATLAS/CMS, allowing the measurement of the spatial position and arrival time of outgoing protons emerging almost intact from the collision. Forward proton tagging in this region is expected to open a new programme of electroweak, QCD and BSM physics. At present the 420m region is enclosed in a 'connection cryostat' (maintained at 1.9K) that provides continuity for the LHC beam, cryogenic & vacuum services and electrical power circuits through superconducting bus bars. The requirement of near room temperature operation and critical position control close to the beam pipes has made inserting FP420 detectors in this region a very complex task. The currently favoured design calls for the replacement of the connection cryostats with a new ~12m long assembly that will have all the necessary features of the existing connections cryostat as well as the appropriate environment for the operation of the detectors. This paper mainly describes the cryogenic aspects of the new connection cryostat. | ||
| TUPMA005 | Simulation Study on Bunch Lengthening | 106 |
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| The bunch lengthening phenomenon is resulted from one of the most severe single bunch instabilities in electron storage rings. As for BEPCII, controlling the bunch length is the most critical task to fulfil the designed luminosity goal. A new code is developed to calculate the single bunch length and energy spread in storage rings using FORTRAN. In this code, the wake field is calculated using an analytical formula. The bunch length and energy spread under different bunch current are calculated for BEPCII. The tracking results clearly show that the microwave instability threshold is around 65 mA for BEPCII storage ring. The tracking results of this code are in good accordance with those from other codes. | ||
| TUPMA006 | Study on the BEPCII Lattice | 109 |
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| BEPCII, the upgrading project of the Beijing Electron-Positron Collider (BEPC), has been designed with a luminosity of 1033 cm-2s-1 at the -charm energy region. According to the beam-beam simulation results, the luminosity of BEPCII with a crossing collision angle of 11 mrad is about 0.50×1033 cm-2s-1 with the original operation mode at the working point of 6.53/5.58. To increase the operating luminosity of the BEPCII, a low momentum compaction factor (?P) collision mode has been studied which can increase the luminosity to 0.54×1033 cm-2s-1. If the bunch length of the low ?P mode is reduced from 1.5 cm to 1.2 cm, a mode with vertical beta function at IP equal to 1.2 cm could push the luminosity to 0.828×1033 cm-2s-1 at the working points 6.53/5.56. Also, the BEPCII synchrotron radiation mode is optimized to get a larger dynamic aperture and much more stable tunes. | ||
| TUPMA008 | Status of the VEPP-4M Electron-Positron Collider | 112 |
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| Since 2004, the principal high-energy physics experiment carried out at the VEPP-4M electron-positron collider is precise measurement of the tau-lepton mass. Moreover, a series of experiments to improve measurement accuracy of the J/psi, psi(2s) and psi(3770) mesons has been performed. During all the high-energy physics experiments, absolute calibrations of beam energy by the resonant depolarization method and routine energy monitoring using the Compton back-scattering technique were realized. Monitoring of beam energy spread, which is also important, was implemented using several techniques. To provide the VEPP-4M high performance, some investigation and further development of the machine have been done, the most important results are described. | ||
| TUPMA012 | Measurement of Bremsstrahlung Dependent on Stored Beam Current | 115 |
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| Bremsstrahlung was measured as a function of stored beam current using the BGO scintillation spectrometer at the compact superconducting storage ring of Ritsumeikan University. Bremsstrahlung is emitted for collision of stored electrons and residual gas on the beam orbit. Yield of bremsstrahlung depend on stored beam current and residual gas density. We tried to determine gas density on the beam orbit by present measurement. | ||
| TUPMA014 | State of the SLS Multi-bunch Feedback | 118 |
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| In order to control coupled bunch oscillations in the SLS storage ring, feedback systems for all three planes were forseen. The filters are realized as fully digital bunch by bunch systems. With the development of dedicated Analog to Digital and Digital to Analog Converter boards, the feedbacks could be commissioned. Important parts of the computations for the transverse planes could be implemented into the ADC FPGA, making the DSPs originally planned to be used obsolete and allowing for an extremely low latency time of 200 ns. The systems give a larger freedom in the choice of the beam optics and also lead to a better closure of the injection bump during top up mode. | ||
| TUPMA015 | Radiation Safety Considerations of the Operation of INDUS-1 Synchrotron Radiation Source | 121 |
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| Radiological safety aspects of the operation of the electron storage ring, Indus-1 (450 MeV, 100 mA) is described in the paper. The ring is provided with a modular hybrid shielding comprising of mild steel and lead through which synchrotron radiation (SR) beam lines pass out. During the commissioning phase several radiation protection problems like streaming of high-energy bremsstrahlung x-rays, through front ends of SR beam lines, shield joints, its detection and containment were encountered. Experimental measurements on the response of conventional radiation monitors with respect to water phantom were then carried out to evaluate the dose build up factors in the streaming high-energy radiation field. The studies lead to the deduction of correction factors for the monitors for use in Indus-1. Improvement in monitor response on account of spectral degradation through shield and radiation levels during accidental beam loss are other problems, which are evaluated. Details of the radiation protection programme, radiation physics studies, the current status of radiation levels and access control are presented. | ||
| TUPMA016 | Computation of Wakefields and Impedances for the PETRA III Longitudinal Feedback Cavity | 124 |
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| At DESY the existing PETRA II storage ring will be converted into a 3rd generation synchrotron radiation source, called PETRA III. The total beam current is limited by coupled bunch instabilities, which are mainly driven by the parasitic modes of the RF cavities. It is planned to use longitudinal and transverse feedback systems to achieve the design current of 100 mA. Eight single cell feedback cavities will be installed into the PETRA III ring to damp the coupled bunch longitudinal phase oscillations. It is important to know the contribution of the feedback cavity to the impedance budget of PETRA III. In this article, the wake and impedance computation results, using the loss and kick parameters, will be reported. The computer codes MAFIA and Microwave Studio have been used to compute the electromagnetic fields. | ||
| TUPMA018 | Compact Hard X-Ray Synchrotron Radiation Source with Superconducting Bending Magnets | 127 |
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| Synchrotron radiation (SR) with relatively hard spectrum (up to 50 keV) is necessary for realization many modern X-ray analytical methods. These methods can be effectively used in industrial and medical applications, in universities and scientific centers. So, the task of developing of compact source of hard synchrotron radiation is very perspective. Budker INP has a big experience for developing and fabrication of high field superconducting insertion devices for different SR centers. In frame of this activity a superconducting bending magnet with field up to 9.6 T was fabricated for BESSY-II and commissioned in 2004. This magnet also became a prototype for compact hard SR source. A project of such storage ring is under developing in Budker INP now. This design fixed beam energy to 1.2 GeV, ring circumference about 52 m. Estimated horizontal equilibrium emittance will better than 20 nm. This report includes a detailed description of main parameters and magnetic structure of designed storage ring as well as preliminary design of injector system and beamline layout. | ||
| TUPMA020 | Beam Based Alignment and COD Correction for the Siam Photon Source | 130 |
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| The first systematic Beam based Alignment (BBA) and COD correction attempt for the Siam Photon Source has been performed. Automated measurements were carried out using MATLAB OPC Toolbox, interfacing to the PLCs of the accelerator control system. Calculations of theoretical parameters were performed with Accelerator Toolbox via MATLAB interface. Since the Beam Position Monitors (BPMs) were not properly calibrated prior to installation beam based calibrations were carried out. Preliminary calibration factors for each BPM were obtained by normalizing BPM signals to modeled steering magnet responses. Measurements of offsets between BPM and quadrupole centers were performed by fitting for minima of orbit response to changes of quadrupole strengths. The resulting offsets were superimposed to the BPM readings in the PLC. COD correction was then performed. | ||
| TUPMA022 | Construction Progress of the SSRF Injector | 133 |
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| SSRF (Shanghai Synchrotron Radiation Facility) is a 3rd generation synchrotron radiation source facility under construction. To meet the full energy top-up injection requirements of 3.5GeV storage ring, the injector of SSRF was designed which consists of a 150 MeV linac, a two super-periods 28 cells FODO type booster and two transfer lines (LT and HT). The cycle rate of booster is 1~2 Hz. SSRF was started building in the end of 2004, and the commissioning of accelerator part will be completed in April 2008 according to schedule. The Booster will start the commissioning until Oct 2007. Now most of on-line installing components, power supplies, and instruments are under manufacture or purchasing for SSRF booster. In this paper, the description of SSRF booster design, the progress of booster and transfer lines construction are described. Keywords: SSRF; booster; construction | ||
| TUPMA023 | Project of 2 GeV Synchroton Light Source for the Republic of Kazakhstan | 136 |
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| Applications of synchrotron radiation (SR) are very popular for last time in many research fields. Thus a developing of compact source for generation of hard X-ray synchrotron radiation is very actual task. The goal of this work is a developing project of SR source for Republic of Kazakhstan. This storage ring mainly dedicated for performing the high sensitive X-ray fluorescence analysis of different natural samples to be used for ore exploration, ore processing and metallurgy . But implementations of other popular techniques applied for research and education with using synchrotron radiation (XAFS, XRD, etc) are also possible. This report includes a detailed description of main parameters and magnetic structure of designed storage ring as well as preliminary design of injector system. | ||
| TUPMA026 | A Prototype of the SSRF Power Supply Control System | 139 |
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| The Shanghai Synchrotron Radiation Facility (SSRF) is a third generation, 3.5GeV synchrotron light source currently being constructed at the Shanghai Institute of Applied Physics (SINAP) in Shanghai, China. There will be approximately 700 magnet power supplies (PS) in the storage ring, booster, linac and transport lines. According to the requirement of control precision, reliability and stability of the magnet power supplies, we decided to use the PSI-designed PS control system for PS control. Each magnet PS has a local digital controller for a digital regulation loop and a 5MHz optical point-to-point link to the VME level. The low-level EPICS interface is identical for all magnet power supplies. Industry Pack (IP) modules with standard carrier cards are used as VME interface with eight links per VME card. The VME-based front-end consists of a PowerPC7455 SBC board, IP carriers and IP I/O modules. A prototype of the PS control system has been setup and tested at SINAP. Control and monitoring of the prototype has been implemented with EPICS toolkit. This paper describes the progress and software development of the prototype, and discusses our near future plan. | ||
| TUPMA028 | Status of the Photon Factory | 142 |
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| Two synchrotron light sources are in operation at the High Energy Accelerator Research Organization (KEK): the Photon Factory (PF) storage ring and the Photon Factory Advanced Ring (PF-AR). The 2.5-GeV PF storage ring was largely upgraded during March to September, 2005. Through this upgrade, existing ten straight sections were extended in length, and four short-straight sections were newly created. New short-period undulators were then installed in the new sections. Other developments, including a top-up injection, are in preparation. The other light source, the 6.5-GeV PF-AR, is routinely operated with a single bunch. It provides high-flux hard X-rays for research including time-resolved pulse X-ray experiments. In the PF-AR, four in-vacuum undulators and one elliptically polarized multipole wiggler are in operation. Moreover, a new in-vacuum undulator was installed in summer, 2006. Some operational developments were also carried out. In this presentation, we report both hardware and operational advances of the PF and the PF-AR storage rings. | ||
| TUPMA031 | Development of Trigger and Clock Delay Module with Ultra-wide Range and High Precision | 145 |
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| Pump and probe experiments using pulse lasers and synchrotron radiation require precise timing relation between the laser pulse and the RF signal of the accelerator. The pulse laser needs clock signal for a mode-locked oscillator and trigger signal to a regenerative oscillator. The delay time of these two signals were usually adjusted by using a mechanical phase shifter or a cable delay. They have disadvantages of short tuning range or discontinuity in the clock signal. We developed a new delay module, which can continuously change the delay time with the range of ±1 s and the precision better than 5 ps. The key point of the module is combination of an IQ modulator and a synchronous counter. The IQ modulator can change the phase of the RF signal with infinite amount with high precision in both plus and minus direction, which is used to produce the laser clock. The phase-modulated RF signal is also fed to the synchronous counter and its output is used to the trigger of the regenerative oscillator. The effectiveness of this module was confirmed by an experiment carried out at the SPring-8. Detail composition of the module, its application and performance are described in the paper. | ||
| TUPMA032 | Radiation Safety System for INDUS Accelerator Complex | 148 |
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| Indus Accelerator Complex consists of a 450 MeV electron storage ring Indus'1 and 550-2500 MeV booster-cum-storage ring Indus-2, which is under commissioning. A common injector system that feeds these rings consists of a 20 MeV microtron & a 450-600 MeV booster synchrotron. Hazardous ionizing radiation is emitted from the accelerators of a facility like Indus. Therefore, it is mandatory to install a Radiation Safety System (RSS) at such a facility. The essential constituents of such a RSS are:·Shielding structure for protecting the personnel from ionising radiation;·Detection and monitoring of the radiation levels inside & outside the shielded area;·Protection system for ensuring that nobody is inside the shielded area when the facility is in operation. The radiation safety system was set-up in stages. The RSS for microtron and booster synchrotron was set-up first followed by that for Indus-1 ring. For Indus-2, it was commissioned in July 2005. These systems were then integrated and have been performing as intended. This paper presents the integrated radiation safety system of Indus Accelerator Complex with emphasis to important features of Indus-2 RSS. | ||
| TUPMA034 | Operation Experience of Top-up injection at Taiwan Light Source | 151 |
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| The storage ring of Taiwan Light Source (TLS) has one Superconducting (SC) cavity, one SC wavelength shifter, and two SC wigglers installed during last two years. The operation mode was also upgraded to have the capability of top-up injection. Top-up is an operation mode in which the beam current is maintained above certain level by frequent injections in the storage ring. The current stability maintains in the range of 10-3 for long period of operation. It provides constant thermal loading on all components in the storage ring and the optics components of beamlines, as well as constant signal to the beam position monitor. The top-up injection is a routine operation mode during user shifts at TLS. Statistics, operation experience and future expansion will be discussed in this paper. | ||
| TUPMA035 | SCSS Prototype Accelerator Timing System | 154 |
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| SPring-8 Compact SASE-FEL Source (SCSS) project is in progress. To verify its feasibility, the 250MeV SCSS prototype accelerator (SPA) was constructed and beam commissioning started in October 2005. We observed first lazing of 49nm wave length in June 2006. In this paper, we describe the timing system of SPA. The target time jitter was selected under 1ps. To achieve this, A master trigger generator unit (MTU), a master trigger distribution unit, a 5712MHz synchronous trigger delay unit (TDU) and a level converter unit were newly developed. The MTU generates a 1-120Hz master trigger to drive all accelerator components synchronously from 60Hz AC line and 238MHz RF. The TDU is an 8ch 24bit delay counter to generate required timing signals for each component using the master trigger from the MTU. The TDU uses 238MHz RF as a counter clock and uses 5712MHz RF to recover the circuit jitter and to synchronize to the electron beam. The time jitter of 0.71ps in the TDU was achieved. We measured the time jitter between an electron beam and a 5712MHz RF that is a main acceleration RF frequency, and obtained 0.34ps. This demonstrates good stability of SPA. | ||
| TUPMA036 | Comparative Studies of Electron Sources for a Free Electron Laser at PSI | 157 |
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| Within the low emittance gun project LEG, the Paul Scherrer is currently conducting research into the development of a high brightness electron source suitable for free electron laser. The gun, planned to generate up to 5.5 Amperes of beam current, consists of a pulsed DC diode followed by a 1 1/2 cell RF gun. Using specialized codes, the performance of field emitter arrays is evaluated assuming realistic geometries. As alternatives, we examine the performance of using individual macroscopic field emission tips or conventional photo emission using copper cathodes. For these, optimized cathode geometries are presented and the performance is compared to that of field emitter arrays. | ||
| TUPMA037 | Project of Infrared Storage Ring Free Electron Lasers at AIST | 160 |
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Development of free electron lasers (FELs) with a compact storage ring NIJI-IV in the near and middle infrared regions is planned in National Institute of Advanced Industrial Science and Technology (AIST). Infrared FELs with a linear accelerator have already been developed and used for various applications in many FEL facilities. However, there is no storage ring FEL (SRFEL) which can oscillate in those regions widely. Although an SRFEL is inferior to a linear accelerator FEL in the average power, it has an extremely stable wavelength and its line width is as narrow as that of a monochromatic light in a synchrotron radiation facility. The average power of the synchrotron radiation in an infrared beam line is about 10 micro-watt at most. Then the SRFEL can be expected as a light source which is more intense than the synchrotron radiation. The output power which is our target is 1 mill-watt. We are aiming at SRFEL oscillations in a wavelength region from 1 to 10 micron which include the fingerprint region partly.
sei.n@aist.go.jp |
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| TUPMA038 | Start-up of an FEL Oscillator from Shot Noise | 163 |
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In free-electron laser (FEL) oscillators, as in self-amplified spontaneous emission (SASE) FELs, the build-up of intra-cavity power starts from shot noise resulting from the discreteness of charge in the electron bunch. It is important to do the start-up analysis for the build-up of intracavity power in order to fix the macropulse width from the electron accelerator such that the system reaches saturation. In this paper, we show that one can use the time-dependent oscillator code GINGER [1] to perform this anlysis. we present results of this analysis for the parameters of the Compact Ultrafast TErahertz FEL (CUTE-FEL) [2] being built at RRCAT.
1. W. Fawley, 'A user Manual for GINGER and Its Post-Processor XPLOTGIN}},LBNL-49625-Rev. I' ed., Lawrence Berkley National Laboratory (2004).2. S. Krishnagopal et al., Proceedings of FEL conference (2006) 496. |
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| TUPMA039 | Comparison of Codes for Smith-Purcell FEL | 166 |
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Smith-Purcell FELs using low energy electron beam are being seen as attractive option for a compact source of coherent Terahertz ratiation. Recently, Kumar and Kim [1] have performed numerical simulation of Smith-Purcell free-electron lasers (SP-FELs) based on a computer code using Maxwell-Lorent equations. Li et al. [2], and Dounhue et al. [3] have performed calculations using PIC codes. In this paper, we present a comparision of these methods and compare results obtained using different codes.
1. V. Kumar et al., Phys. Rev. E 73, 026501 (2006). 2. D. Li et al., Phys. Rev. ST Accel. Beams 9, 040701 (2006). 3. J. T. Donohue et al., Phys. Rev. ST Accel. Beams 9, 060701 (2006). |
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| TUPMA042 | Beam Parameters of the SCSS Prototype Accelerator Designed by PARMELA and Comparison with Measured Values | 169 |
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The 250 MeV prototype facility of the SCSS X-FEL project was constructed in the Octorber 2005 and the machine commissioning was started in May 2006. One month later, we have succeeded in confirming the amplification of the synchrotron radiation. The electron beam parameters, such as peak current and emittance, have been designed and estimated using PARMELA. In contrast to other X-FEL projects, the SCSS injector uses a thermionic pulsed electron gun [1]. Compared with RF photocathode guns, the thermionic gun is stable and easy to handle. Its peak current, however, is smaller, and the compression of the electron bunch is necessary at early stage of the low beam energy injector. In this report, we compare the simulation and measured values, such as a bunch length and projected emittance, on the SCSS prototype accelerator. The measured beam parameters, after the bunch compression procedure and emittance degradation due to space charge, show fairly good agreement with the simulation.
[1] K. Togawa, et al., “Emittance Measurement on the CeB6 Electron Gun for the SPring-8 Compact SASE Source”, Proceedings of the 2004 FEL Conference, (2004)351-354, URL: http://www. JACoW.org. |
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| TUPMA046 | Future Light Source based on Energy Recovery Linac in Japan | 172 |
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| After extensive discussions on the future light source of the Photon Factory at High Energy Accelerator Research Organization (KEK), it has been concluded that a 5 GeV energy recovery linac (ERL) should be the most suitable candidate to foster cutting edge experiments and support a large variety of user needs from VUV to X-rays. On the other hand, Japan Atomic Energy Agency (JAEA), which has already built a low energy (17 MeV) ERL, also proposed its own 5-6 GeV ERL as a light source. These two institutes with a participation of the members of the Institute for Solid State Physics (ISSP) of the University of Tokyo agreed to promote an ERL-based next-generation synchrotron light source in Japan. In order to realize a 5 GeV ERL, it is necessary to construct a prototype ERL with an energy of ~200 MeV and develop several critical components such as electron guns and superconducting accelerating structures. We are planning to construct together the prototype ERL at the KEK site. An R&D team for the prototype ERL is going to be organized in collaboration with accelerator scientists from the other facilities, UVSOR and SPring-8. | ||
| TUPMA047 | Development of a Photocathode DC Gun at JAEA-ERL | 175 |
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| An electron gun producing an e-beam with high-brightness and high average-current is a key component to realize a next-generation X-ray light source based on energy-recovery linac (ERL). In JAEA, we are developing a photocathode DC gun for a future ERL light source. The DC gun is operated at 250 kV and 50 mA at maximum, and equipped with a load-lock chamber for cathode preparation. In order to keep small emittance at high current operation, we adopt superlattice semiconductor as a photocathode. In this paper, we present the status of the gun development and future plans towards the ERL test facility to construct in collaboration with KEK. | ||
| TUPMA049 | Development of an Injector to Generate a Very Short Bunch for a Super Coherent Terahertz Light Source Project | 178 |
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| A project to develop a coherent Terahertz (THz) light source is in progress at Laboratory of Nuclear Science, Tohoku University. The coherent synchrotron light in the THz region is emitted from electron bunches with a very short bunch less than 100 fs (rms) generated by a thermionic RF gun and a sophisticated bunch compressor. As an injector of this ring, we have developed an independently tunable cells (ITC) RF gun and a magnetic bunch compressor. The longitudinal phase space extracted from the ITC-RF gun can be manipulated by feeding RF microwave to cells independently. To generate a short bunch with a significant bunch charge, a magnetic compressor is used downstream from the gun. Two kinds of bunch compressors have been studied. From simulation of an injector, we have got a very short bunch length about 42 fs (rms). A prototype of the gun has been manufactured. Results of low power tests of the gun will be presented. | ||
| TUPMA052 | Study on Compact DC Electron Gun using Single Crystal Cathode of LaB6 | 181 |
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| A novel, compact DC gun has been designed and is currently on a test bed at LNS. Applying 50 kV high voltage for the gun, it is expected to supply a high brightness beam of which the beam current of 300 mA and the variable pulse duration from 1 to 5 ?sec. In addition, a floating bias voltage can be applied between the cathode and the wehnelt to manipulate electric field near cathode surface. In order to produce lower emittance beam, the thermionic cathode should have very much higher current density and the size of that should be very small. Consequently we have chosen single crystal LaB6 as the thermionic cathode, which can provide higher current density with good homogeneity electron emission. The design parameters and initial operating experience of the DC gun are discussed. This DC gun will be used for free electron lasers such as backward-wave oscillator, advanced accelerator researches and other experiments. Results of numerical calculations show good distribution of macroparticles in the phase space, which results from optimization of the bias voltage. A normalized rms emittance at the exit of the gun is expected to be less than 1 ? mm mrad. | ||
| TUPMA053 | Injection Optimisation for INDUS-2 | 184 |
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| In this paper commissioning experience of injection into INDUS-2, a 2.5 GeV synchrotron radiation source is discussed. In initial stage of commissioning, partial beam loss was observed. In this context effect of various injection errors such as mismatch between pulse widths, jitter and magnetic field stability of kickers on injected and stored beam are studied1. A brief summary of the results is presented. After reducing jitter and fine adjustments of timings of kicker power supplies, partial beam loss reduced significantly. | ||
| TUPMA056 | Injection of Beam Shaped Locally with Nonlinear Optics | 187 |
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| We discuss nonlinear beam shaping by octupole and sextupole to fold the tail of a Gaussian beam into its core, for the purpose of improving betatron injection in storage rings by significantly reducing the beam width at the injection septum and thus reducing beam centroid offset from the stored beam. Necessary conditions as well as challenges for such nonlinear injections are explored. | ||
| TUPMA057 | Physics Design of PAL-XFEL Undulator | 190 |
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| Pohang Accelerator Laboratory(PAL) is planning a 0.3 nm – 0.45 nm SASE (Self Amplification of Spontaneous Emission) XFEL based on 3.7 GeV linear accelerator. It is targeting utilization of 0.1 nm X-ray radiation using the 3rd harmonic FEL radiation. With 3.7 GeV electron beam energy, achieving 0.3 nm fundamental FEL lazing is very challenging and it requires very low emittance electron beam with minimum energy spread. It also requires small period undulator with very small gap. In this context, application of SPring8 type in vacuum undulator is seriously considered. This reflects the experiences from SPring8 SCSS project. In this report, the physics design efforts of the undulator is described. The periodic parts are optimized to achieve the highest field with other requirements. The end structures were designed to be asymmetric along the beam direction to ensure systematic zero 1st field integral. The thickness of the last magnets were adjusted to minimize the transition distance to the fully developed periodic field. The final design features 4 mm minimum pole gap, 15 mm period, peak effective field of 1.09 Tesla. | ||
| TUPMA058 | Insertion Devices for SESAME | 193 |
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| SESAME is a 3rd generation synchrotron light source that is optimized for the use of Insertion Devices. In this note, the magnetic design for a Hybrid Multipole Wiggler (HMW) and an Elliptically Polarizing Undulator (EPU), proposed for the Phase-I beamlines of SESAME will be presented. Both devices fulfill the electron beam stay clear requirements defined by the SESAME lattice leading to a decent vacuum lifetime. The HMW will provide photon energies from 3-25 keV, which are defined by the scientific case of the SESAME storage ring. The HMW is a hybrid device with period length of 160 mm, a minimum gap of 14.5 mm, maximum flux density of 2.10 Tesla and total magnetic length of 3.04 m. A maximum photon flux density of 1.80×1015 photons/sec/0.1%BW is obtained. The EPU device is required to provide the SESAME users with a variable polarized light and high photon flux over the energy range of 100-1500 eV. The proposed design is of Apple-II type with a period length of 60 mm, a minimum gap of 13 mm and a total magnetic length of 1.782 m. Only the helical mode of operation has been considered where horizontal, vertical and elliptical polarized light can be obtained. | ||
| TUPMA059 | Beam Dynamics Effects with Insertion Devices for the Proposed 3 GeV Ring in Taiwan | 196 |
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| The effects of insertion devices on beam dynamics of storage rings were studied. We will focus on the changes of the emittance and energy spread in the presence of insertion devices. Formulas for the beam emittance and the energy spread with insertion devices are also derived, in which an intrinsic parameter depending on the design of the lattice is introduced in the calculations. Simulation results and comparisons of achromatic and non-achromatic cases in the proposed 3 GeV synchrotron radiation light source in Taiwan are shown. | ||
| TUPMA060 | A Hamiltonian for Wave Length Shifter and its Studies on INDUS-1 | 199 |
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| The INDUS-1 is a 450 MeV synchrotron radiation source for the production of VUV radiation. In order to produce the radiation of shorter wavelengths(lc = 31 Ao), a superconducting wavelength shifter (WLS) with peak fieldof 3T is being considered for Indus-1. In this paper, L. Smith's Hamiltonian for Halbach's magnetic field model has been re-derived to estimate focussing component under the compensated electron beam trajectory transformation. Various linear compensation schemes are presented to minimize the linear effects of the WLS and its effects on machine operation are also theoretically studied. | ||
| TUPMA064 | ILC Activity at JINR and Siting in Dubna Region | 202 |
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| JINR actively participates in ILC project. JINR physicists are planning to take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, etc. Moreover Joint Institute is full-member pretender for possible hosting of ILC in the region near Dubna. International intergovernmental status of JINR, comfortable location of site, well developed infrastructure, geological, climate and relief conditions may become powerful advantages of Dubna siting among other proposals of ILC location. All above mentioned topics are discussed in the presented report. | ||
| TUPMA066 | Energy Equalization by using S-band and X-band Accelerator Modules | 205 |
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| To reduce the beam loss and to restrict the expanse of the bunch length of the positron beam from the KEKB injector, the energy spread of ±0.25% or less is required for the beam transport line of the KEKB ring. Generally, the positron beam has a large energy spread because the original bunch length is large and all positrons do not see the same accelerating filed. Thus, an energy compression system which consists of six rectangular magnets and two 2-m S-band accelerating structures is implemented at the end of the linac but it has a demerit that the beam bunch is lengthened. We propose a new method to suppress the energy spread without enlarging the bunch length. This method utilizes the superimposed acceleration of the S-band modules and X-band modules. | ||
| TUPMA067 | New Timing System for the L-band Linear Accelerator at Osaka University | 208 |
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| A highly precise and flexible timing system has been developed for the L-band linac at ISIR, Osaka University. It provides four RF signals and several timing signals for operation of the linac and for experiments with the linac. In order to realize long-term stability of the timing system and hence operation of the linac, a rubidium atomic clock producing a 10 MHz RF signal with the fractional stability of 10-15 is used as a time base for a synthesizer used as a master oscillator for generating the acceleration frequency of 1.3 GHz. The 1.3 GHz signal from the master oscillator is directly counted to produce the four RF signals and the clock signal of the timing system at 27 MHz. The master timing signals for linac operation is taken from the AC line frequency and it is synchronized with the 27MHz clock signal precisely. To make an arbitrary delayed timing signal, a standard digital delay generator is used to make a gate signal for a GaAs RF switch, with which one of the 27MHz clock pulses is sliced out to generate the delay timing signal. Any timing signal can be made in an interval of 37 ns and the timing jitter of the delayed signal is achieved to be as short as 2 ps. | ||
| TUPMA068 | Performance of the Renewed L-band Linac and Recent Progress of Development of FEL and SASE at Osaka University | 211 |
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| The 40 MeV, L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University is used for various studies on advanced beam sciences. The linac was constructed in 1975-1978 and largely remodeled in 2002-2004 for higher operational stability and reproducibility. We have evaluated performance of the renewed linac. The beam intensity is measured for longer than an hour at the exit of the linac operated in the transient mode for pulse radiolysis experiments in the nanosecond region. The intensity fluctuation is 0.27 %, which is one tenth of the value before remodeling. We are conducting development of an FEL and basic study of SASE in the far-infrared region with the linac. The experiment was suspended and resumed again after the remodeling. We have developed a strong focus wiggler for FEL and SASE based on the edge-focusing scheme, which can make the current density of the electron beam and hence the gain of FEL higher. The renewed linac can provide a long pulse electron beam up to 8 us for FEL and we are now commissioning the linac in this operation mode. We will report the performance of the renewed linac and recent development of FEL and SASE. | ||
| TUPMA070 | Progress of RFQ Accelerator at Peking University | 214 |
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| The progress of two RFQ accelerators at Peking University is presented: one is Separated Function RFQ (SFRFQ), which separates the focusing and acceleration of traditional RFQ to get higher acceleration efficiency. The first prototype of the SFRFQ is designed to accelerate O+ from 1MeV to 1.5MeV and used as a postaccelerator for ISR RFQ-1000 (Integral Split Ring) [1]. The other is high current deuteron 201.25MHz RFQ, it will accelerate 50mA D+ beam to 2MeV with a duty cycle of 10%. The design study of SFRFQ and high current Deuteron RFQ accelerator are outlined. | ||
| TUPMA075 | Status of the CTF3 Frequency Multiplication Rings | 217 |
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| The CLIC Test Facility (CTF3) is in construction at CERN by an international collaboration to demonstrate the feasibility of two beam acceleration scheme at the CLIC parameters. The drive beam of the CTF3 is composed by a fully loaded Linac that generates a long bunch train and two rings that provide the high current and bunch frequency multiplication by interleaving bunch trains. The status of the commissioning of the first ring (Delay Loop) and of the transfer lines are reported together with the installation of the second ring (Combiner Ring). | ||
| TUPMA076 | Design and Development of Beam Transport Elements for the BARC-ECIL Linac | 220 |
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| A 10 MeV, 2 kW RF electron linac is under development for cargo scanning. It consists of electron gun, RF linac structure, solenoid focusing magnets, steering magnet, beam diagnostics and x-ray target. The beam diameter requirement at the target is 2mm. Since the beam is to be focused to a diameter of 2mm at the target; the transverse beam optics of the whole linac structure from gun end to the target has been simulated by solving the beam envelope equation. The beam envelope equation has been solved in radial direction by Runga-Kutta method consisting of external focusing field, RF fields, beam perveance and emittance. Various combinations of solenoid magnet focusing have been studied. It has been found that three solenoid magnets are required to focus the beam to a diameter of 2mm at the target, two between the electron gun and the linac entrance and the other between the linac exit and the target. Based on these studies two solenoid magnets has been designed and fabricated. Details of beam optics simulation results and the design of the solenoid magnets will be presented. | ||
| TUPMA083 | High Quantum Efficiency Photocathode for RF Guns | 223 |
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| High Quantum Efficiency Photocathodes are nowadays routinely used as electron sources for laser driven RF guns. In this paper, we review the production, characterization and operation performances of the Cs2Te photocathodes prepared at INFN Milano – LASA and operated at DESY for the FLASH and the PITZ photoinjectors. | ||
| TUPMA084 | Ions for LHC: Status of the Injector Chain | 226 |
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| The LHC will, in addition to proton runs, be operated with Pb ions and provide collisions at energies of 5.5 TeV per nucleon pair, i.e. more than 1.1 PeV per event, to experiments. The transformation of CERN's ion injector complex (Linac3-LEIR-PS-SPS) to allow collision of ions in LHC in 2008 is well under way. The status of these modifications and the latest results of commissioning will be presented. The remaining challenges are reviewed. | ||
| TUPMA085 | LEIR: Towards the Nominal Lead Ion Beam | 229 |
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| The Low Energy Ion Ring (LEIR) is a central piece for LHC ion operation at CERN, transforming long Linac3 pulses into high density bunches needed for LHC. The first phase of LEIR commissioning successfully attained its goal of providing the so-called 'early ion beam' (one bunch of 2.25 108 Lead ions) needed for the first LHC ion runs with reduced luminosity. Studies in view of generating the beam needed for nominal ion operation (2 bunches of 4.5 108 ions in LEIR) are being carried out in parallel with the setting-up of the early beam in the accelerators further downstream in the LHC injector chain. The main characteristics of the machine using a new state of the art electron cooler are discussed together with the latest results. | ||
| TUPMA088 | High Power RF Testing of a Cell Coupled Drift Tube LINAC Prototype for LINAC4 | 232 |
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| A Cell-Coupled Drift Tube Linac (CCDTL) accelerating structure at 352 MHz has been selected for the energy range 40 to 90 MeV of Linac4, a new injector linac for the CERN accelerator complex. With regard to a conventional DTL in this energy range this structure presents the advantages of lower construction cost and easier access, cooling and alignment of the focusing quadrupoles placed between tanks. A full-scale high-power prototype of about 1/3 of a complete module has been designed and built at CERN. It is fed by a waveguide input coupler of novel conception. This paper summarizes the main mechanical features of the prototype and reports the results of low-power and high-power RF testing. | ||
| TUPMA093 | Thermo-structural Analysis of 400 KeV Deuteron RFQ Components | 235 |
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BARC is developing technologies for a high current low energy proton accelerator, which includes a 3MeV RFQ. As part of this, a 400 KeV prototype deuteron RFQ has been planned. This RFQ will also be utilized later to replace 14 MeV neutron generator at BARC. In this paper we are presenting Thermo-structural analysis of RFQ and features such as RF Coupler, Tuner, Vacuum port etc. This investigation will lead to design of local cooling schemes of these components. Parametric studies are also included in this paper. Feasible Cooling schemes which meet cooling requirements of components will also be discussed.
e-mail:piyushj@barc.gov.in |
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| TUPMA094 | Electron Cooling Rates in FNAL's Recycler Ring | 238 |
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| A 0.1-0.5 A, 4.3 MeV DC electron beam provides cooling of 8 GeV antiprotons in Fermilab's Recycler storage ring. The paper presents cooling rate formulas derived in the framework of a simple non-magnetized model and compares them with measurements. | ||
| TUPMA097 | Characteristics of the Magnetic Channel in the Yoke Hole of K-500 Superconducting Cyclotron | 241 |
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| The detail magnetic field measurement of K-500 superconducting cyclotron has been carried out. The last magnetic channel of the extraction system placed in the yoke hole of the cyclotron before external beam line is active, unlike others, which are all passive. This channel comprises a coil and a special shaped iron to produce both quadrupole and dipole field for focussing and radially aligning the different ion species coming out from the cyclotron, with the external beam transport line. The magnetic field inside the channel along with the outside stray field has been measured for different channel currents as well as main magnet excitations. A 3-D model of the full magnet is constructed using magneto- static code RADIA [2] to simulate the yoke field. This paper reports the comparative study of measured and calculated field and studies the trajectories for the representative ions through the stray field calculated from the model. The later being used to locate the starting point (or matching point) for the external beam transport line | ||
| TUPMA099 | Adiabatic Damping of the Bunch-length in the Induction Synchrotron | 244 |
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A fact that a bunch-length shrinks with the barrier-bucket acceleration in the induction synchrotron [1], where a single proton-bunch injected from the 500 MeV Booster was accelerated to 6 GeV in the KEK-PS, has been observed [2]. This has been supposed to be simply explained by a term of adiabatic damping. A technique to analytically deal with such an adiabatic dumping in a case of RF bucket acceleration is well-known; a WKB solution is employed for the small amplitude synchrotron oscillation. However, the simple WKB approach is not available for the present barrier-bucket acceleration, because the longitudinal motion always depends on the oscillation amplitude. A novel technique capable of quantitatively predicting the adiabatic phenomenon in the barrier-bucket acceleration has been newly developed. It turns out that the experimental result, numerical simulation, and analytic prediction have been in good agreement with each other. Theoretical approaches tell us that a bunch-length in the barrier-bucket acceleration never continues to shrink but achieves a constant value corresponding to the time duration between barrier voltages.
[1] K. Takayama and J. Kishiro, Nucl. Inst. Meth. A451/1, 304-317 (2000)[2] K. Takayama et al., “Experimental Demonstration of the Induction Synchrotron”, published soon. |
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| TUPMA102 | Installation and Radiation Maintanance Scenario for J-PARC 50 GeV Synchrotron | 247 |
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| Installation and assembling of accelerator components for J-PARC 50 GeV Synchrotron are now underway. Off-beam commissioning will be carried out between December 2007 and April 2008, and the full commissioning of J-PARC accelerator complex, which is consisted of an injector linac, a 3 GeV rapid cycling synchrotron and the 50 GeV Synchrotron, will be started from May 2008. This paper describes the status, schedule and method of installation and assembling of accelerator components. Radiation maintenance scenario will be also described. | ||
| TUPMA105 | Transverse Matching of the SNS Linac Based on Profile Measurements | 250 |
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For a high intensity linac such as the SNS linac, it matters to match to minimize the beam mismatch and potential beam loss. It was observed that matching was improved through the matching technique based on the beam profile measurements from wirescanners.
*SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. |
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| TUPMA108 | Benchmarking of Multiparticle Phase Scan and Acceptance Scan Techniques for the SNS DTL | 253 |
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For a high intensity linac such as SNS Drift Tube Linac, it matters to accurately determine the rf set-point of the tank rf field to minimize beam mismatch and potential beam loss. Two techniques were benchmarked which are multiparticle phase scan and acceptance scan techniques. Excellent agreement was obtained between the set-points obtained from the two techniques. The analysis of both techniques are based on multiparticle tracking using the Parmila code.
*SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. |
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| TUPMA109 | Thermal-Induced Frequency Detuning of 350 MHz RFQ Structure | 256 |
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| A 350 MHz, 4.5 MeV RFQ structure is being studied for proposed High Power Proton Linac for Indian SNS. At high RF duty operation of RFQ due to RF induced heating the structure would be subjected to thermal deformations and hence the detuning of resonating structure from its designed resonating frequency. A detailed Thermal-Structural-Electromagnetic sequential analysis of RFQ has been performed using Multi-physics ANSYS (Finite Element Analysis Software). A cooling scheme has been worked out to get the efficient heat removal from the structure to minimize the thermal induced frequency shift. During analysis the parameters such as cooling water flow rate, cooling water inlet temperatures, cooling channel locations, cavity thickness etc. are varied to study the effect of these parameters on temperature distribution and associated frequency variation. The frequency shift is found highly sensitive to vane tip cooling parameters. | ||
| TUPMA111 | Present Status of J-PARC MR Synchrotron | 259 |
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| The Japan Proton Accelerator Research Complex (J-PARC) is a joint project of High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA). The J-PARC accelerator complex is composed of a 400 MeV proton linac, a 3 GeV Rapid-Cycling Synchrotron (RCS), and a 50 GeV Proton Synchrotron (MR). Installation of the MR which has two extraction sections, fast extraction for the Neutrino Facility and slow extraction for the Hadron Facility, is now underway. Test of injection and extraction components such as septum magnets and kicker magnets is progressed as well. Beam commissioning scenario is now being prepared. Maintenance scenario of activated components is also crucial in a high power proton accelerator. Beam commissioning will start in May 2008. | ||
| TUPMA113 | Design of High Current RF Ion Source for Micromachining Applications | 262 |
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| Liquid Metal Ion Source (LMIS) and Gas Field Emission Ion Source (GFEIS) are the major ones in micromachining applications so far. They have limitations of contaminations and low throughput respectively. Plasma based ion sources can produce heavier ions for higher throughput, lighter ions for fabrication of higher resolution structures, ions for doping, ion assisted direct writing of metallic, oxide, nitride and carbide layers and lines. Considering wide range of applications, a 13.56 MHz inductive coupled plasma (ICP) ion source for producing high brightness ion beams with very low energy spread has been developed. It is a very compact ion source with external helical antenna wound around a 30 mm quartz tube. 1 mA of Argon and 0.5 mA of proton ion beams have been extracted from 2 mm dia aperture in plasma electrode at 3.5 kV extraction potential and ~200W of RF power. Using LabView software and field point modules, an automated plasma diagnostic system has been designed and used to measure the plasma parameters. This paper describes the features of the ion source, ion beams produced, some results of the plasma diagnostics. | ||
| TUPMA115 | Simulations of Non-uniform High Density Electronegative Plasma for Optimization of H- ions and their Extraction | 265 |
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| Numerical simulations of radio frequency multi-cusp volume type H- ion source have been performed under non-uniform electronegative plasma equilibrium conditions in order to understand the physics of formation of various ion species (H+, H-, e- etc.) and for optimization of H- ion formation and extraction. Coupled momentum balance equations along with continuity equations were solved in a cylindrical geometry to obtain the density profile of various ion species. The relevant cross-section data available in the literature as a function of temperature has been used in the computation. The hydrodynamic model of plasma in equilibrium with background neutral gas has been used. Low degree of ionization ( ~1%) has been assumed. The collision less sheath formation, penetration of electric and magnetic field and power requirement to sustain the plasma has been worked out numerically. An effort has been made to give a self-consistent numerical scheme for the solution of inductively coupled plasma (ICP) in equilibrium, and the results obtained have been presented | ||
| TUPMA116 | Periodic Ion Current Burst in 6.4 GHz ECR Source | 268 |
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| We studied the enhancement in extracted ion current in the 6.4 GHz ECR ion source at VECC, Kolkata by inserting a negatively biased disc in the main stripping stage. In addition to the expected increase in current, we observed a sudden jump in the current at some low bias voltage. The jump amplitude is larger for higher charge states. In order to understand the origin of the jump, we recently measured the time spectra of high charge state ion current for neon. The time spectra revealed the presence of a burst frequency in the kilohertz range. This frequency shows a correlated jump with the ion current described above. Another feature is that the observed burst frequency shows a good linear correlation with the extracted ion current. This may signify that current per burst is a constant factor, higher current means that there are more number of bursts. | ||
| TUPMA119 | Beam Line Design for PEFP User Facility | 271 |
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| In the Proton Engineering Frontier Project (PEFP), 20MeV and 100MeV proton beams from a 100MeV proton liner accelerator will be supplied to users for beam applications. The basic lattice for beam transport line will be FODO from the linac to the targets. Dipole magnets exited with shaped AC currents will distribute the beam from the linac to five targets simultaneously. To provide flexibilities of irradiation conditions for users from many application fields, we design beam lines to the targets with wide or focused, external or in-vacuum, and horizontal or vertical beams. The details of the beam line design will be reported. | ||
| TUPMA122 | High Power Neutron Converter for Low Energy Proton/Deuteron Beams: Present Status | 274 |
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| In BINP, Russia, the high temperature neutron target for SPES project (INFN-LNL, Italy) is proposed. The target is designed to produce up to 10**14 neutron per second within the energy range of several MeV under irradiation by proton/deuteron beam of power up to 200 kW. By now the target prototype is successfully tested. The development of liquid metal driving system and target general design is started. Presented paper describes the design of the target and the target prototype as well as the results of prototype tests under high-power electron beam. Special attention is paid to the carbon material with high content of 13C isotope. The material is produced following the original technology and used for manufacturing the converter irradiated with the proton beam. | ||
| TUPMA123 | Electron Acceleration in the Wake Field Excited by 200TW Femto Second Laser in Underdense Plasma | 277 |
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| Laser-plasama acceleration experiment has been carried out using 200TW, 30fs Ti:Sapphire laser pulses focused on helium gas-jets with F/8.75 optics. Intense mono-energetic electron beams have been produced by controlling plasma length and density precisely. Energy spectral oscillations in respect to ejection angle have been also observed. Measurements of images from Thomson scattering and fluorescence side scattering from plasma indicate highly relativistic effects such as a long self-channeling, hosing instability and filamentation. It seems that these nonlinear phenomena strongly disturb high energy gain acceleration and high quality beam generation. | ||
| TUPMA124 | Multipacting in a Coaxial Cavity | 1 |
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| Residual Gas Molecules on Multipacting |