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| TUPB06 | First Tests with the Sis18 Digital BPM System* | acceleration, pick-up, synchrotron, instrumentation | 66 | ||
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In this paper we describe new approaches for BPM (Beam Position Monitor) measurements, needed in hadron accelerators which have strongly varying beam parameters, such as intensity, accelerating frequency and bunch length. After the data collection and offline evaluation in 2005, first FPGA implementations of algorithms were completed in 2006 and tested at SIS18 and CERN PS. Main aspect of the first tests was the proof of concept in terms of online calculation feasibility. This includes online calculation of the needed integration windows as well as the baseline restoration algorithms. The realization of the hardware and the data handling are discussed. Least squares techniques were used for parametric fitting to gain bunch signal properties which can be used to monitor beam position.
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*Founded by EU FP6-Design Studies |
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| 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, storage-ring, electron, controls | 102 | ||
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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.
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| TUPC12 | FPGA based Frame Grabber for Video Beam Diagnostics | controls, radiation, diagnostics, proton | 174 | ||
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TV-based accelerator diagnostics are widely used for machine operation and beam diagnostics. It is planned to renew the video memory modules of the TV monitor data acquisition systems for the injection and transfer lines at DESY. New FPGA based Frame Grabber (FG) modules were developed within this project. The modules are required to be able to work with different analog signal formats, to capture video frames on trigger and to provide live mode operation. The main feature of this FG is the possibility of reprogramming. This allows us to optimize its functionality, for example to operate with non-standard or corrupted video signals. This has proved especially useful for grabbing images from CCD-cameras suffering from radiation damage.
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| WEPC07 | Injection Diagnostics Using Triggered Bunch-by-Bunch Data Acquisition | kicker, collider, diagnostics, storage-ring | 322 | ||
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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.
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| WEPC10 | Tune, Coupling, and Chromaticity Measurement and Feedback During RHIC Run 7 | feedback, coupling, betatron, controls | 331 | ||
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Tune feedback was first implemented in RHIC in 2002, as a specialist activity. The transition to full operational status was impeded by dynamic range problems, as well as by overall loop instabilities driven by large coupling. The dynamic range problem was solved by the CERN development of the Direct Diode Detection Analog Front End[1]. Continuous measurement of all projections of the betatron eigenmodes made possible the world's first implementation of coupling feedback during beam acceleration, resolving the problem of overall loop instabilites[2,3]. Simultaneous tune and coupling feedbacks were utilized as specialist activities for ramp development during the 2006 RHIC run. At the beginning of the 2007 RHIC run there remained two obstacles to making these feedbacks fully operational in RHIC - chromaticity measurement and control, and the presence of strong harmonics of the power line frequency in the betatron spectrum. Preliminary investigations of power line harmonics were presented earlier[4]. We report here on progress in tune, coupling, and chromaticity measurement and feedback, and discuss the relevance of our results to the LHC commissioning effort.
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[1] M. Gasior and R. Jones, DIPAC 2005, Lyon, p.312.[2] P. Cameron et. al., PRST-AB, Dec 2006. [3] R. Jones et. al., DIPAC 2005, Lyon, p.298.[4] P. Cameron et. al., DIPAC 2005, Lyon, p.33. |
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