iThemba LABS, Somerset West
FZJ, Jülich
Non-destructive beam position monitors (BPMs) have been in use at iThemba LABS for several years in the neutron therapy and radioisotope production beamlines, as well as in the transfer lines between the K200 separated-sector cyclotron and the two K8 injector cyclotrons. The sensitivity of these BPMs is limited by noise and pickup from the RF systems to about 300 nA in the high energy beam lines. For proton therapy, using the scattering method, position measurement at beam currents as low as 20 nA have to be made. A new and more sensitive BPM as well as the electronic measuring equipment, using RF pickup cancellation and improved filtering, have been developed and installed in the proton therapy beamline. The BPM, the electronic equipment and the results of measurements at beam currents down to 10 nA for 200 MeV protons are described.
ESRF, Grenoble
The ESRF Storage Ring has, in the period of the last 3 winter months, been fully equiped with new electronics for its BPM system while causing a minimum disturbance to its large community of X-ray beam-line users. The Libera-Brillance is now actively doing the treatment of the weak RF signals on all of the 224 BPM stations, and has replaced the old RF-Multiplexing system that had served reliably for nearly 17 years. This paper will describe the precautions that had been taken to make the whole transition as smooth and fluid as possible, with regards to both the reliability for the SR operation and the positional stability of the X-ray beams for the users of more than 40 beamlines. Information will be given on the structure of the network and computer control, based on the Tango distributed control system and its associated device-servers and tools. Results obtained will be presented to demonstrate the strongly improved performance and functionality in every field of application, and that will make this new BPM system the key component in the near future’s upgraded orbit stabilization system.
CERN, Geneva
A convenient way of having beam bunch intensity information available all around the LHC ring is to use the beam position monitor (BPM) system. The principle is to add the BPM signals, process them and make the result compatible with the time-modulation method used for transmitting the position over a fibre-optic link. In this way the same acquisition system can make both position and intensity data available. This paper describes the technique developed and presents the first intensity measurements performed on the CERN-SPS and LHC.
U. Erlangen-Nurnberg LHFT, Erlangen
Siemens Med, Erlangen
For beam position monitoring purposes, particle-in-cell simulations were applied to investigate pickup button and electron beam spectrum characteristics. Results on this simulative approach are presented. Particularly, a comparison is made between simulation results from the PIC solver of CST’s PARTICLE STUDIO and experimental data gathered with a 6 MeV electron beam from a linear accelerator for medical purposes. The measurements were conducted under non-vacuum conditions. Good agreement between simulation and experimental data was achieved although non-negligible electron spread during air passage of the electron beam can be assumed.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
BERGOZ Instrumentation, Saint Genis Pouilly
An alternative to a BPM with a continuous detector/ADC clock distributed from a synchronised with beam master generator is a self-synchronised BPM where the clock is manufactured from the beam signal itself. In a single-shot BPM of such kind [1], which is being designed for the EMMA Accelerator, the ADC should execute several subsequent fast rate measurements with a clock burst triggered by the bunch on each turn. We investigated a work of some fast pipeline-type ADCs suitable for BPMs, in a burst regime where a minimal burst length is decided by the ADC latency. The results did show that pipeline-type ADCs a main merit of whose is a high precision are usable in single-shot BPMs. We discuss how to prevent some ADC resolution deterioration that typically occurs at first samples, and to attain an ultimate ADC resolution in a single-shot BPM.
[1] A. Kalinin, Towards Sub-Micrometer Resolution of Single-Shot Strip Line BPM, EUROTeV-Report-2008-056.
PSI, Villigen
The resonant stripline pickup was chosen for a Beam Position Monitor (BPM) developed for the 250 MeV PSI XFEL Injector to reach the desired sensitivity of 10 micrometers in beam position. The electromagnetic design of this cavity, performed with Microwave Studio, was optimized in terms of the main radiofrequency characteristics - frequency, shunt impedance, Q value - of the resonant modes of interest, in order to obtain the pickup sensitivity required by the electronics (direct sampling, [*]). Also mechanical aspects of the design are presented, with particular attention to the solution adopted for the stripline alignment. Based on the simulated geometry, a pickup prototype was carried out and tested, allowing to verify the correct characteristics of the resonant modes and to state the present resonant stripline pickup design as one possible candidate for the standard (non-undulator) BPM system of the PSI XFEL and also for other linear accelerators or storage ring transfer lines.
[*]: B. Keil, S. Lehner. S. Ritt, "Application of a 5 GSPS Analogue Ring Sampling Chip For Low-cost Single-shot BPM Systems", Proc. EPAC 2008, Genoa, Italy, 1167 (2008).
BNL, Upton, Long Island, New York
SLAC, Menlo Park, California
CERN, Geneva
We present the performance and limitations of the SPS exponential coupler for transverse instability measurements with LHC type beam. Data were acquired in 2008 in the SPS in the time domain with a bandwidth of up to 2.5 GHz. The data were filtered to extract the time evolution of transverse oscillations within the less than 5ns long LHC type bunches. We describe the data filtering techniques and reveal the limitations of the pick-up due propagating modes.
Fermilab, Batavia
KEK, Ibaraki
To achieve a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring, the BPM read-out system is currently upgraded with new high resolution electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducable beam position readings. The concept and its technical realization, as well as preliminary beam study results are presented.
DESY, Hamburg
The new synchrotron light source PETRA III is powered by a chain of pre-accelerators including Linac II, PIA, transfer lines, and DESY II. The whole chain is equipped with upgraded versions of diagnostic systems that were installed during the 2008 shutdown. This paper presents the upgrade of the beam position monitor (BPM) systems at PIA together with the transfer lines and DESY II. All systems rely on the ‘Delay Multiplex Single Path Technology’ (DMSPT). It is demonstrated that the self-triggered design of the BPM electronics is specifically suited to the different needs of such a heterogeneous pre-accelerator chain. Structures and dependencies of the BPM systems will be described in detail.
University of Oslo, Oslo
CERN, Geneva
Uppsala University, Uppsala
IN2P3-LAPP, Annecy-le-Vieux
The two-beam acceleration scheme foreseen for CLIC and the associated radio-frequency (RF) components will be tested in the Two-beam Test Stand (TBTS) at CTF3, CERN. Of special interest is the performance of the power extraction structures (PETS) and the acceleration structures as well as the stability of the beams in the respective structures. After the recent completion of the TBTS, the first 12 GHz PETS has been tested with beam. Up to 30MW of RF power was extracted from a 5A electron beam, using so called recirculation of the RF power inside the PETS. The TBTS instrumentation, including inductive beam position monitors, allows precise measurement of beam parameters before and after the PETS as well as RF power and phase. Measurements of transverse kicks, energy loss and RF power with recirculation are discussed and compared with estimations, including first measurements of RF pulse shortening probably due to break down.
CERN, Geneva
During the 2008/2009 shutdown the electronics for the Fast Wire-scanners for the CERN PSB and PS machines will be renovated with new movement and acquisition electronics. A new test bench was produced that allows measuring the movement of wires at speeds up to 20 m/s. This poster will present the calibration system with its related software.
Fermilab, Batavia, Illinois
LBNL, Berkeley, California
Electron cloud density in the Fermilab Main Injector was measured by observing microwave transmission along the vacuum tube. Presence of the electron cloud reduces the velocity of the microwave signal. Both frequency and time domain methods reveal relative cloud density and time evolution. The effect of beam time structure is clearly evident. The accelerator magnetic field effects the distribution of electrons making it difficult to estimate density.
PSI, Villigen
This contribution gives an overview of transverse sub-micron beam position measurement systems and techniques for 3rd and 4th generation light sources and collider projects. Topics discussed include mechanical, electrical and digital design aspects, environmental influences, machine operation and design considerations, as well as system- and beam-based measurement and calibration techniques.
MPI-K, Heidelberg
At the Max-Planck-Institute for Nuclear Physics in Heidelberg a cryogenic electrostatic storage ring (CSR) is under construction, which will be a unique facility for low velocity and in many cases also phase-space cooled ion beams. Among others the cooling and storage of molecular ions in their rotational ground state is planned. To meet this demand the ring must provide a very low level of blackbody radiation and a vacuum in the XHV range (10-15 mbar) which is achieved by cryogenic cooling of the ion beam vacuum enclosure to 2-10K. The beam current will be in the range of 1 nA -1 μA. The resulting low signal strengths together with the cold environment put strong demands on the amplifier electronics. We plan to make use of a resonant amplifying system. Using coils made from high purity copper, we expect quality factors of ~1000. The mechanical design has to provide stability of the alignment against thermal shrinking when switching from room temperature operation to cryogenic operation. A prototype pickup has been built in order to test resonant amplification and the mechanical design with a wire. The amplification principle will be tested in the MPI-K’s Test Storage Ring.
DESY, Hamburg
PETRA III, a new high-brilliance synchrotron radiation source, is under commissioning at DESY. Its beam position measurement system is based on the Libera Brilliance electronics. BPM system is used for machine starting up and development. The system will also be used for the beam observation and orbit feedback. This paper presents the infrastructure, features of the BPM system and experience with the commissioning of the BPM electronics.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
The Ultra-low energy Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) at GSI, Germany will decelerate antiproton beams of very low intensities from 300 keV down to 20 keV. Such beams can be easily disturbed by standard monitoring devices and the development of new sensitive diagnostic techniques is required. To overcome the limitations related to a very low number of particles, a low signal-to-noise ratio and ultra-low kinetic energies, a resonant capacitive pick-up has been proposed as a beam position monitor. In the planned solution, the signal gain will be realised by the use of a specially designed resonant circuit optimized to meet the requirements of the USR. The current overall design studies of the resonant capacitive pick-up, including simulations of the beam displacement sensitivity and linearity for different pick-up geometries and the equivalent resonant circuit optimisation, will be discussed.
DELTA, Dortmund
TU Dortmund University, Dortmund
Orbit stability at the 1.5 GeV electron storage ring DELTA is currently achieved via a global slow orbit feedback system at a data acquisition rate of 10 Hz. The system is based on analog Bergoz MX-BPMs and I-Tech Libera digital BPMs. In order to enhance the precision of the slow position measurement and in preparation for a global fast orbit feedback at a 10 kHz data acquisition rate we developed an FPGA based digital frontend for the MX-BPMs. The prototype module is taking orbit data from 4 Bergoz MX-BPMs, clocked to 40 kHz, at a rate of 10 kHz while averaging over 4 samples per clock cycle. The digitized data is distributed via the Diamond Communication Controller [*] formerly only available for Libera BPMs. Precision, fault tolerance and easy maintenance are the key aspects of this system. First operational tests in the storage ring showed that the system reveals the desired capabilities. The paper will give an overview on the layout of the FPGA-based system, will report on the results with beam and will show prospects for the further use at DELTA.
*I. S. Uzun et al., "Initial Design of the Fast Orbit Feedback System for Diamond Light Source", Proc. 10th ICALEPCS
INFN/LNF, Frascati (Roma)
ELETTRA, Basovizza
The single pass functionality available in the recent release of the Libera Brilliance software, takes particular interest when compared with requirements of FEL machines, that need stable and precise control of the beam trajectory throughout Linacs and transfer lines in order to meet the stringent beam quality and transverse position constraints inside undulators. Results from tests performed on Libera with beam from ELETTRA, SPARC and DAΦNE, operating in Sincrotrone Trieste and LNF Frascati, are reported to characterize the resolution of single shot transverse beam position measurements.
IMP, Lanzhou
HIRFL-CSR, a new heavy ion cooler-storage ring in China IMP, had been installed and started commission from 2005. We report here the BPM system on the main ring (CSRm) and the experimental ring (CSRe). The BPM structure, the signal processing system and on-line measurement experiments are presented. The measurement results such as turn-by-turn bunch observation, closed-orbit measurement, Schottky noise measurement are also presented in this paper.
IFIC, Valencia
A set of two Inductive Pick-Up (IPU) prototypes with its associated electronics for Beam Position Monitoring (BPM) in the Test Beam Line (TBL) of the 3rd Compact Linear Collider (CLIC) Test Facility (CTF3) at CERN were designed, constructed, and tested by the IFIC team. One prototype and two units of the series production are already installed in the TBL line. In the first part of the paper we describe the characterization tests of these two prototypes carried out at CERN, and the first beam tests performed to one of them. The second part of this paper is dedicated to the description of the issues addressed by the start of the series production and the characterization tests of the first series units performed with a custom-made low-frequency wire setup. This setup which emulates the beam position variation allows to carry out the series tests in an automatized manner and with higher accuracy.
GANIL, Caen
The SPIRAL2 project is composed of an accelerator and a radioactive beam section. Radioactive ions beams (RIBs) will be accelerated by the current cyclotron CIME and sent to GANIL experimental areas. The accelerator, with a RFQ and a superconducting Linac, will accelerate 5 mA deuterons up to 40MeV and 1 mA heavy ions up to 14.5 MeV/u. A new electronic device has been evaluated at GANIL to measure phase and amplitude of pick-up signals. The principle consists of directly digitizing pulses by under-sampling. Phase and amplitude of different harmonics are then calculated with a FPGA by an I/Q method. Tests and first results of a prototype are shown and presented as well as future evolutions.