DESY, Hamburg
By using magnetic chicane bunch compressors, high-gain free-electron lasers are capable of generating femtosecond electron bunches with peak currents in the kilo-ampere range. For accurate control of the longitudinal dynamics during this compression process, high-precision beam energy and arrival-time monitors are required. Here we present an electro-optical detection scheme that uses the signal of a beam pickup to modulate the intensity of a femtosecond laser pulse train. By detecting the energies of the laser pulses, the arrival-time of the pickup signal can be deduced. Depending on the choice of the beam pickup, this technique allows for high-resolution beam position measurements inside of magnetic chicanes and/or for femtosecond-resolution bunch arrival-time measurements. In first prototypes we realized a beam position monitor with a resolution of 3 μm (rms) over a many-centimeter dynamic range and a bunch arrival-time monitor with a resolution of 6 fs (rms) relative to a pulsed optical reference signal.
BNL, Upton, Long Island, New York
The Faraday Cup Award is given for an outstanding contribution to the development of an innovative particle beam diagnostic instrument of proven workability. It is presented at the Beam Instrumentation Workshop (BIW), a biennial forum for in-depth discussions of techniques for measuring particle beams produced in accelerators. This session will present the latest Faraday Cup winner, and the Proceedings article associated with it will summarize the history of the award. After the award is presented, this year's honoree (a secret until the Workshop) will give a talk on the design and performance of the winning instrument. For more information on the Award, see http://www.faraday-cup.com.
CERN, Geneva
This presentation will detail the performance achieved to date with all the main LHC beam instrumentation systems. It will include an overview of the beam loss system and its role in machine protection, along with that of the beam position system and its use for automatic orbit control. Results will be shown from the highly sensitive base band tune system as well as the bunch-by-bunch and DC beam current transformer systems, the synchrotron light monitoring systems, the wire scanner system and OTR screens. It will also cover the US-LARP contribution to the LHC in the form of results from the collision rate monitors developed by LBL and the Schottky monitors developed by FNAL.
CERN, Geneva
CLASSE, Ithaca, New York
PSI, Villigen
In the CLIC project, highest luminosity will be achieved by generation and preservation of ultra low beam emittances. It will require a mechanical stability of the quadrupoles down to 1 nm rms above 1 Hz through up to 24 km of linac structures. Studies are being undertaken to stabilize each quadrupole by an active feedback system based on motion sensors and piezoelectrical actuators. Since it will be very difficult to prove the stability of the magnetic field down to that level of precision, an attempt was made to use a synchrotron electron beam as a sensor and the beam motion was observed with a standard button BPM equipped with high resolution electronics. Hence in two consecutive experiments at CESR-TA (Cornell University, Wilson Lab) and at SLS (PSI-Villingen) the residual eigenmotion of the electron beam circulating in these two machines was measured in the frequency range 5700 Hz. This paper describes in detail the achieved results alongside with purpose of the measurement, the equipment used for observation of the beam rest-motion, and the vibration measurements of mechanical machine elements.
UniDo/IBS, Dortmund
iThemba LABS, Somerset West
FZJ, Jülich
DELTA, Dortmund
The interaction of an ion beam with the residual gas might lead to a photon emission of the excited residual gas molecule. These photons can be used to monitor the beam profile. Therefore a multichannel photomultiplier is used together with an optical system. Measurements at the COSY synchrotron are presented. The usability of the method is discussed by comparing to measurements at the iThemba Labs beam line and the JESSICA experiment, a spallation source prearrangement at COSY.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
The gas ionisation beam profile monitor is a well established piece of diagnostic hardware. The use of active devices such as micro-channel plates (MCP’s) and channeltrons within such a diagnostic can present problems with gain differences between channels. At the Rutherford Appleton laboratory we have produced a beam profile monitor that uses an array of 40 individually powered channeltrons; these devices were chosen over the MCP for their robustness and longer lifetimes. These channeltron devices (like MCP’s across their surface) can suffer from large variations in gain at the desired operating voltage. We have successfully shown that an additional in-built calibration system using a single, motorised , channeltron can overcome these issues. We report on the work to build the calibration system, and the 40 channeltron array. The PXI (National Instruments) system used to control the motor drive and provide the all data acquisition is also covered. Also we report the new high voltage drift field to reduce space charge effects on the beam profile. Ongoing work on understanding how the drift field as well the beam field affects the measured profile is also discussed.
I-Tech, Solkan
SOLEIL, Gif-sur-Yvette
Libera Photon is the new Photon Beam Position Processor (PBPM) from the Instrumentation Technologies. First measurements on real beam have been done at SOLEIL Synchrotron. The module was connected to a PBPM installed on the DIFFABS bending magnet beam line. Three different beam position experiments were done: measurement of position at beam bump (± 500 μm), beam current dependence and filling pattern dependence. Measurements were done with internal BIAS voltage source set to -70 V. Measured current was in the range up to 250 μA on the sensor. Measurements were done on standard 100 kS/s, 10 kS/s and 10 S/s data flows with different bandwidths. The article discusses the results and consequential improvements of the device.
SLAC, Menlo Park, California
SSRL designed and built beam position electronics for its SPEAR3 storage ring. We designed the electronics, using digital receiver technology, for highly accurate turn by turn measurements of both the position and arrival time of the beam, allowing us to use this system to measure the betatron and synchrotron tunes of the beam. The dynamic range of the system allows us to measure the properties of the beam at currents ranging from those of single bunch injection to those of the full SPEAR stored beam. This paper discusses the architecture of the electronics, presents their performance specifications, and shows a range of applications of this system for accelerator physics experiments.
DESY, Hamburg
PETRA III is a high brilliant synchrotron light-source operating at 6GeV. The commissioning of the machine began in April 2009 *. In the first months of operation the Machine Protection System (MPS) ran on basic requirements to protect absorbers and vacuum chambers in the damping wiggler section and the undulator section against synchrotron light. Therefore several alarms distributed along the machine are identified and within 100us a dump command is created. The beam is dumped within 300us by switching of the rf system **. Prior the first user runs different improvements increasing the reliability and availability are planned and partly implemented in the MPS. This paper presents first commissioning results of the system and gives an overview of these new implementations as well as a more detailed discussion of some alarm conditions and the dump procedure. Additionally some key aspects of the Temperature Interlock as one major alarm-deliverer are described.
SLAC, Menlo Park, California
BNL, Upton, Long Island, New York
Life Imaging Technology, Palo Alto, California
For top-up injection it is important to understand the time evolution of the incident charge in the transverse and longitudinal coordinate systems. In SPEAR3, the injection system has a vertically-deflecting Lambertson septum with the injected beam entering ~13mm to the inside. The resulting large-amplitude betatron oscillations give rise to rapid filamentation followed by nominal radiation damping and in some cases non-linear x-y coupling. Similarly, in the longitudinal dimension, a mis-match in beam arrival time or energy can result non-linear beam dynamics and damped synchrotron motion. To the next order, any betatron, bunch length or energy spread mismatch will generate damped ‘quadrupole’ oscillations or even higher-order motion. In this paper we report on measurements of injection beam dynamics in the transverse and longitudinal coordinate systems using a fast-gated, image-intensified CCD camera and a Hamamatsu C5680 streak camera, respectively. The injection beam dynamics are shown to contain relatively complicated evolution in the x-y-z beam distributions that change with injection conditions and storage ring lattice configuration.
GSI, Darmstadt
To avoid beam losses of intense beams stored at the GSI heavy ion synchrotron SIS-18 a precise tune measurement during a whole acceleration cycle is required. This contribution presents a sensitive method of tune determination using data of Beam Position Monitor (BPM) measured in bunch-by-bunch manner. The signals induced in the BPM electrodes were digitized by 125 MS/s and integrated for each individual bunch. The tune was determined by Fourier transformation of the position data for typically 512 subsequent turns. Coherent betatron oscillations were excited with bandwidth-limited white noise. The presented method allows for tune measurements with satisfactory signal-to-noise ratio already at relatively low beam excitation i.e. without a significant increase of transverse beam emittance. In parallel the evolution of transverse beam emittance was monitored by means of Ionization Profile Monitor. The system for online tune measurement is an integral part of the new digital BPM System, presently under commissioning.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The ALBA Booster synchrotron is designed to ramp an electron beam of up to 4 mA from 100 MeV to 3 GeV in a 3 Hz cycle. The Booster is equipped with two common λ/4 striplines for tune excitation and precise beam position measurement. Beam excitation along the cycle requires the amplitude kick to increase synchronously with the energy ramp. This paper shows the excitation and measurement system at ALBA, including both mechanical and hardware instrumentation as well as control system functionalities.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The ALBA Booster is a synchrotron designed to accelerate electron beam from 100 MeV to 3 GeV in a 3 Hz cycle. The maximum pulse coming from the ALBA Linac provides 4 mA in the Booster. In order to check all the Booster sub-systems, a Booster pre-commissioning took place during two weeks between December 2009 and January 2010. This paper presents the Diagnostics elements installed in the ALBA Booster and our experience during the Booster pre-commissioning.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
Beam position monitors (BPM) characterization has been widely studied at ALBA Synchrotron Light Source. Special care has been taken on the analysis of their electrical offset in order to achieve submicron beam stabilities. This paper shows the results of the BPMs offset study for Booster and Storage Ring. The electrical effect of the different vacuum vessels housings the BPMs is also reported.
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is a 3 GeV synchrotron light source which being in construction at NSRRC. Designs of various diagnostics are undergoing and will deploy in future to satisfy stringent requirements of TPS for commissioning, operation, and top-off injection. Design of the diagnostics for beam intensity observation, trajectory and beam positions measurement, destructive profile measurement, synchrotron radiation monitors, beam loss monitors, orbit and bunch-by-bunch feedbacks, filling pattern, etc. are in final design phase. Details of current status and implementation of the planned beam instrumentation system for the TPS will summary in this report.
BNL, Upton, Long Island, New York
A synchrotron light diagnostic beamline has been designed at the NSLS-II storage ring, using the dipole radiations. A "cold-finger" configuration has been selected to block the central x-rays. Beam power on the first mirror is less than 1 W, so no water cooling was required for this in-vacuum mirrors. The beamline layout and major applications will be discussed in this paper. Two vacuum ports are reserved in the NSLS2 booster ring to monitor the transverse profile as well as bunch length measurement during ramping. There will be a synchrotron light port in the BTS transport line for observing the injecting beam behavior during top-up operation.
Agilent Technologies SA, Plan-les-Ouates
Agilent Technologies Inc., Loveland
Digital data acquisition in real time applications falls into two categories: digitizing a stream of data without missing a single sample point, and capturing a stream of triggered events without missing a single trigger. Maintaining these data streams over long periods requires an optimized combination of analog signal conditioning, and precise digitization, digital data reduction and high-speed data transfer. This paper describes suggested methods to reduce the amount of measurement data required, reduce the amount of that data that is to be transferred (to a measurement where possible), and then transfer this reduced data in the most rapid fashion. Our approach uses a combination of hardware, firmware and software elements that are designed to work together, optimizing performance and managing the data bottlenecks. New hardware standards and architectures are discussed that improve the capabilities of today's technologies, providing access to higher data and measurement flux. Applications presented in this paper include high trigger rate capture for beam steering and fill pattern monitoring in charged particle accelerators.
PSI, Villigen
JLAB, Newport News, Virginia
Electro Optical (EO) sampling is a promising non-destructive method for measuring ultra short (sub-ps) electron bunches. The FEMTO slicing experiment at the Swiss Light Source modulates about 1 pC of the 4-nC electron bunch longitudinally. The coherent synchrotron radiation (CSR) emitted by this substructure was sampled by 100 fs long pulses from an Yb fiber laser in EO crystals of different materials (GaP, ZnTe). The broadening of this ps long structure over several turns of the synchrotron could be measured with sub-ps resolution.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
DITANET is the largest-ever EU funded training network in beam diagnostics. The network members – universities, research centres and industry partners – are developing diagnostics methods for a wide range of existing or future particle accelerators, both for electron and for ion beams. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes schools and topical workshops for the beam instrumentation community. This contribution gives an overview of the Network's research portfolio, summarizes the main research results from the first two years of DITANET and presents past and future training activities.