| Paper | Title | Other Keywords | Page | ||
|---|---|---|---|---|---|
| MOD1A01 | Digital EBPMs at Diamond: Operational Experience and Integration into a Fast Global Orbit Feedback | feedback, power-supply, pick-up, controls | 24 | ||
|
We present out experience with the Libera EBPM during the first months of operation at Diamond. Measurement noise and beam current dependence with beam are compared to earlier lab measurements. Where discrepancies between the performance in the lab and in the application are observed, the causes have been investigated. Furthermore, results of the integration of the EBPMs into a FOFB system are presented, including measurements of orbit motion spectra with and without FOFB.
|
|
|
||
| TUPB18 | Measurement of Electron Beam Charge in the ESRF Accelerator Complex for Absolute and Injection Efficency Measurements Using an FPGA Based Digital BPM Electronics | booster, injection, electron, controls | 102 | ||
|
A Beam Position Monitor (BPM) using Virtex II pro FPGAs (‘Libera Electron’ from Instrumentation Technologies) has been programmed with an alternative firmware in order to determine the charge by measuring integrated RF amplitude, over an adjustable time window, of signals from 4 strip lines. These strip lines are located on the transfer line from the linac to the booster, on the booster ring, on the transfer line from the booster to the storage ring and on the storage ring. By calibrating the RF loss in all the cables, knowing the geometry of the strip lines and using the crossbar switching before the 4 RF ADCs of the Libera, the charge/current can be compared in order to determine the efficiency of transfer at various locations during injection. Since the current in the storage ring is known to a high accuracy using a parametric current transformer (from Bergoz Instrumentation), the absolute charge can be determined at all locations.
|
|
|
||
| TUPB21 | Experience with Libera Beam Position Monitors at DELTA | beam-losses, kicker, diagnostics, pick-up | 111 | ||
|
Libera beam posiotion monitor electronics have been installed at the electron storage ring Delta in order to extend the capabilities of the BPM system to turn-by-turn orbit measurements. This report covers the integration of Liberas into the beam diagnostics infrastructure at DELTA and its control system EPICS. Prior to their application in user runs the devices have undergone characterization measurements in a BPM teststand and during machine runs for accelerator physics. Results of these measurements are compared to measurements with DELTAs standard BPM electronics. The necessary clock and trigger signals are provided by a low-cost signal distribution device developed at DELTA.
|
|
|
||
| TUPB22 | Renewal of BPM Electronics of SPring-8 Storage Ring | betatron, controls, closed-orbit, emittance | 114 | ||
|
The signal processing electronics of the SPring-8 Storage Ring BPM were replaced during the summer shutdown period of the year 2006. Since then, the new electronics have been put into operation for user experiment runs. The purpose of the renewal was to upgrade the performance of the position measurement system, i.e. the position resolution, speed of the measurement, etc. The position resolution of them in the real operation condition was estimated by using the stored beam in the same condition as the operations for user experiments, in the following way. The closed orbit distortions (COD) were repeatedly measured with the interval of 4 seconds in order to obtain the root mean square (r.m.s.) values of differences between two consecutive measurements. Since the obtained r.m.s. values included the intrinsic resolution of the position measurement system and the effect of the beam motion, the effect of the beam motion was separated from the obtained r.m.s. data by assuming that the effect of the beam motion was proportional to the betatron function values at the BPM locations. As a result, the intrinsic resolution was estimated to be 0.1μmeters.
|
|
|
||
| TUPC13 | The new Diode BPM system for ELETTRA | controls, vacuum, undulator, pick-up | 177 | ||
|
A new Beam Position Monitor system has been developed at ELETTRA based on an envelope detector. It is a four channel system reading in parallel the four voltages from a button pick-up that adopts a wide-band Schottky diode. The analogue bandwidth of the currently implemented detector is <1kHz which has been adapted to the present application of the system, i.e. a fast beam position interlock to be installed on the ELETTRA storage ring. The upgrade of the ELETTRA BPM which is based on the Libera detector suggested us to add some redundancy on the fast position interlock in order to protect the vacuum chamber from wrong positions / angles of the beam. The data collection scheme, based on a single board computer for each straight section, is presented. Currently, the system has been installed and tested on all the ELETTRA undulator sections; the first running experience is here presented.
|
|
|
||
| TUPC19 | Matlab Code for BPM Button Geometry Computation | vacuum, booster, controls, linac | 186 | ||
|
Third generation Synchrotron Light Sources with vertical beam sizes down to few microns require beam resolutions on the submicron level. Study of different Beam Position Monitors (BPM) geometries has been done to reach such tight requirements. The used Matlab Graphical User Interface (GUI) is based on the simulation of a charged particle inside a selectable vacuum chamber type, computing the induced signal that it produces on the button feedthroughs. Needed parameters for the computation are the button electrode dimensions, vacuum chamber profile, electron beam current and measurement bandwidth. Output results from the GUI are the induced power on the feedthroughs, BPM sensitivity and intrinsic resolution of the analyzed geometry. As sensitivity and resolution are BPM geometry dependent terms, the Matlab GUI turned out to be an easy and fast way for first step geometry analysis.
|
|
|
||
| TUPC20 | The SOLEIL BPM and Orbit Feedback Systems | feedback, controls, vacuum, instrumentation | 189 | ||
|
SOLEIL is a third generation light source built in France, near Paris. Its BPM system is important for machine studies and for delivering stable beams to the users. A beam stable to 1/10th of the dimensions requires submicron stability in the vertical plane. The monitors, anchored either to the girders or to the ground, are fixed points of the vacuum chamber. Bellows avoid transverse drifts due to mechanical stress. The electronics design was driven by combined efforts through an active communication between accelerator labs (SOLEIL at first, later joined by DIAMOND) and Instrumentation Technologies. The result is the “Libera Electron” beam position processor. It combines a 0.2μm rms resolution and micron level stability for beam delivery with accurate turn-by-turn measurements (3μm resolution at 0.8MHz) for machine commissioning and beam physics studies. It also features position interlock, tune measurement, and postmortem capabilities. A Slow Orbit Feedback for correcting low frequency drifts (0 to 0.1Hz) is currently in operation. The Fast Orbit Feedback to be implemented soon will suppress higher frequency perturbations up to 100Hz.
|
|
|
||
| WEPB21 | Kicker Based Tune Measurement for DELTA | kicker, betatron, feedback, resonance | 277 | ||
|
We have set up a tune measurement for the electron storage ring Delta based on broadband beam excitation with a kicker magnet and measurement of the relaxation betatron oscillations turn-by-turn. By averaging over several kicks the kick amplitude may be as low as 600 nrad in standard user runs at nominal current, leading to negligible beam distortion. Signal to noise ratios in excess of 10 are reliably achieved down to 200 uA beam current using a maximum kicker amplitude of 10 urad. A simple tune feedback algorithm compensates for tune shifts due to vacuum chamber movement and orbit movement in sextupoles.
|
|
|
||
| WEPB22 | Touschek Lifetime Measurement with a Spurious Bunch in UVSOR-II Electron Storage Ring | electron, single-bunch, scattering, vacuum | 280 | ||
|
We have developed a method to measure the Touschek beam lifetime of an electron storage ring using spurious bunches in single-bunch operation by measuring change in the single-bunch impurity over time. To measure a spurious bunch and the main bunch simultaneously, we use a photon counting method with sufficient dynamic range and response time. We demonstrated the method by measuring the Touschek beam lifetime in the UVSOR-II electron storage ring. We find that the Touschek beam lifetime dominates the total beam lifetime in UVSOR-II in usual vacuum condition. The Touschek beam lifetime measurement in multibunch operation with the method will be discussed in the presentation.
|
A. Mochihashi, M. Katoh, M. Hosaka, Y. Takashima, Y. Hori, NIM-A 572 (2007) 1033-1041. |
|
||
| WEPB24 | Machine Protection and Interlock Systems at Synchrotron SOLEIL | vacuum, diagnostics, booster, synchrotron | 286 | ||
|
SOLEIL is a third generation Synchrotron radiation source located in France near Paris, having the classical accelerator structure consisting of a Linac pre-accelerator, a Booster accelerator and a Storage Ring, which are connected by two transfer lines[1]. Since January, the Storage Ring delivers photon beam to 9 beamlines. In order to protect the very sensitive and essential equipment during machine operation, (vacuum chambers, vacuum valves, mirrors, etc.) an interlock system has been implemented. This system is based on industrial and autonomous PLC (Programmable Logic Controller). This paper describes each level of the interlock chain from the diagnostics and vacuum sensors and processes, up to the backbone of the interlock system which stops the RF system.
|
|
|
||
| WEPC07 | Injection Diagnostics Using Triggered Bunch-by-Bunch Data Acquisition | injection, kicker, collider, diagnostics | 322 | ||
|
Quality of injection is very important for reliable and successful operation of colliders and light sources. In this paper we present a technique for real-time monitoring of injection transients in storage rings. We also demonstrate how the data can be used for tuning the injection system. A novel data processing method, coupled with triggered bunch-by-bunch data acquisition system enables one to monitor the effects of the adjustments nearly in real time. The acquisition and postprocessing technique will be illustrated with the data from PEP-II and DAΦNE.
|
|
|