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| TUO1A01 | Bunched Beam Stochastic Cooling for RHIC | proton, ion, pick-up, beam-losses | 39 | ||
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Stochastic cooling is an effective and well-established accelerator technology for improving beam quality. However, stochastic cooling of high frequency bunched beam has always proved problematic. We have built a stochastic cooling system for heavy ions in RHIC that is used on bunched beam. The purpose is to counteract Intra-Beam Scattering and improve integrated luminosity. The chief technical challenge of bunched beam is the strong coherent frequency components in the beam that contaminate the Schottky spectrum. Technical solutions for overcoming this problem are described. Results from commissioning in one ring of RHIC are reported.
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| TUO1A03 | Beam Diagnostic Features of the ESRF Multibunch Feedback | feedback, diagnostics, pick-up, controls | 48 | ||
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The ESRF storage ring is now equiped with a set of multibunch feedback systems. The main goal of the implementation of these systems is to prevent longitudinal and transverse instabilities. However, beside this main function, these systems provide a powerful diagnostic to study the longitudinal and transverse beam dynamic and document operation problems. In this paper we give a short overview of these feedback systems and describe their diagnostics function in more detail.
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| TUPB21 | Experience with Libera Beam Position Monitors at DELTA | beam-losses, diagnostics, storage-ring, pick-up | 111 | ||
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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.
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| TUPB28 | A Large Scintillating Screen for the LHC Dump Line | proton, radiation, photon, controls | 132 | ||
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7 TeV proton beam from the LHC is ejected through a long transfer line to a beam dump block. Approximately 100 m downstream of the ejection septa, a series of dilution kicker magnets provide a sweeping deflection spreading the extracted beam over a 40 cm diameter area on the face of the beam dump core. During normal operation, the quality of each dump event must be recorded and verified. The so called “Post-Mortem” data-set will include information from the beam dumping system as well as from the beam diagnostics along the extraction line. For this purpose, a profile monitor in front of the dump block is permanently available during machine operation. With more than 1014 protons stored in LHC, the thermal properties of the screen have to be considered as beam energy deposition becomes an issue. This paper presents the design of this device, which is original due to its very large size. We introduce the different technical considerations involved in the design of the system and present the complete layout of its installation with a special emphasis on the mechanical design, the screen assembly and the choice of the radiation-hard video camera used to capture the image.
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| TUPC08 | Quadrupole Transfer Function for Emittance Measurement | quadrupole, emittance, pick-up, resonance | 162 | ||
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Historically the use of the quadrupole moment measurement has been impeded by the requirement for large dynamic range, as well as the sensitivity of the measurement to beam position. In this paper we investigate the use of the transfer function technique in combination with the sensitivity and 160dB revolution line rejection of the direct diode detection analog front end to open the possibility of a sensitive emittance diagnostic that may be implemented economically and without operational complication, quasi-parasitic to the operation of existing phase-locked loop tune measurement systems. Such a diagnostic would be particularly useful as an emittance monitor during acceleration ramp development in machines like RHIC and the LHC.
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| WEPB02 | Design of an Intra-Bunch-Train Feedback System for the European X-Ray FEL | feedback, pick-up, dipole, electron | 232 | ||
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After joining the preparatory phase of the European X-ray FEL project, the Paul Scherrer Institute agreed in taking over responsibility for electron beam stabilization by developing a fast intra-bunch-train feedback (IBFB) system, which will be tested in its prototype version at the FLASH linac of the collaboration partner DESY. The proposed IBFB topology consists of two beam position monitors ("upstream BPMs") followed by two kicker magnets for each transverse plane and two more BPMs ("downstream BPMs"). By measuring the position of each bunch at the upstream BPMs and applying suitable transverse kicks individually to the following bunches, the architecture of the FPGA-based digital IBFB electronics (with a latency preferably below the bunch spacing of 200 ns and 1000 ns for the XFEL and FLASH) allows to damp beam motions up to hundreds of kHz. In addition to the FPGA-based feedback, DSPs enable adaptive feed-forward correction of repetitive beam motions as well as feedback parameter optimisation using the downstream BPMs. This paper gives an overview of the architecture and status of the IBFB subsystems being developed, like stripline BPMs, digital electronics and kicker magnets.
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| WEPB21 | Kicker Based Tune Measurement for DELTA | betatron, storage-ring, feedback, resonance | 277 | ||
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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.
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| WEPB28 | First Tests of the Transverse Multibunch Feedback at Diamond | feedback, pick-up, damping, instrumentation | 295 | ||
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This paper describes the design and initial tests of the transverse multibunch feedback system under development at Diamond. The system is designed to damp instabilities up to 250MHz in both the vertical and horizontal plane. This will lead to an increase of instability thresholds which will permit a reduction of chromaticity and thus should improve dynamic aperture and life time.
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| WEPC07 | Injection Diagnostics Using Triggered Bunch-by-Bunch Data Acquisition | injection, 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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| WEPC16 | Excitation Striplines for SOLEIL Fast Transverse Feedback | impedance, simulation, feedback, vacuum | 343 | ||
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SOLEIL, the French third generation light source, is equipped with excitation striplines for a tune monitor and for the (bunch-by-bunch) Fast Transverse Feedback* that has been recently implemented. A careful design of the striplines and their vacuum feedthroughs was aimed at maximizing the effectiveness of the excitation power via high shunt impedances, and minimizing the power taken from the beam via low parasitic mode losses. Three stripline kickers have been developed for these applications. We report on their design using RADIA and GdfidL simulation codes, on the fabrication of the striplines, and on the experimental results with beam.
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* R. Nagaoka: Transverse Feedback Development at SOLEIL. ID 1257 |
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| WEPC23 | Progress of the Diagnostics at the Proscan Beam Lines | controls, diagnostics, quadrupole, emittance | 361 | ||
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PROSCAN, the dedicated new medical facility at PSI using proton beams for the treatment of deep seated tumours and eye melanoma, has entered the operational phase. Air and N2 filled ionisation chambers and secondary emission monitors in several configurations are used as current monitors, profile monitors, halo, position and loss monitors at the PROSCAN beam lines. The operation experience and improvements of these diagnostics as well as of the multi-leaf- and the standard faraday-cups and of the profile-evaluation technique are reported. Additional variants of ionisation chamber position monitors adapted to local requirements are now under construction. Criteria for interlocks which control beam parameters and the correct operation of diagnostics are discussed as well as dedicated procedures for checking the function of the built-in diagnostics. The fast exchange of beam-line components and spare parts are briefly mentioned.
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| WEPC26 | Transverse Bunch-by-Bunch Feedback for the VEPP-4M Electron-Positron Collider | feedback, betatron, coupling, impedance | 367 | ||
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Transverse mode coupling instability (TMCI or fast head-tail) is the principal beam current limitation of the VEPP-4M electron-positron collider. For the high-energy physics experiments at the 5.5 GeV energy, the VEPP-4M bunch current should exceed much the TMCI threshold. To suppress transverse beam instabilities, a broadband bunch-by-bunch digital feedback system is developed. The feedback concept is described, the system layout and first beam measurements are presented.
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