TUPB48 |
Beam Instrumentation for COSY Electron Cooler | |
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| The report deals with beam instrumentation of the electron cooler for COSY storage ring. The electron cooler is an electrostatic accelerator designed for beam energy up to 2 MeV and electron current up to 3 A with recuperation. The electron beam is immersed in longitudinal magnetic field so the electron motion is strongly magnetized. The near-cathode electrode in the electron gun is composed of four electrically isolated sectors. Applying AC voltage to one sector allows tracing of motion of that particular part of the beam. The electron beam shape is registered with the combination of 4-sector electron gun and the BPMs. This method allows observing both dipole and quadruple (galloping) modes of electron beam oscillation. Compass probe for measuring and tuning the direction of magnetic field in the cooling section is described. A profile monitor based on few small faraday caps for measuring distribution of the electron beam is presented. | ||
TUPB49 |
Electron Cloud Density Measurements Using Resonant TE Waves at CesrTA | |
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Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam. |
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TUPB50 |
Development of the GSI Beam Instrumentation for FAIR Facility | |
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| Most challenging for beam instrumentation at FAIR facility is the required high flexibility due to the parallel operation with the beams of different ion species and extremely different beam intensities. This contribution gives an overview of the selected beam diagnostics methods that are under development at GSI in the perspective of FAIR: i) The optimization of the beam injection chain consisting of two linacs is focused on the monitoring of the longitudinal bunch shape and the measurements of the momentum spread by analysis of the incoherent components of the bunch signals. ii) Determination of transversal profiles of the high current ion beams at linear accelerators and transfer lines requires minimal intercepting method. The methods based on OTR fulfilling these requirements were successfully applied in the recent tests. iii) The development of the synchrotron beam diagnostics is focused on design validation of the cryogenic BPM. In addition measurements and interpretation of the transversal beam motions for intense beams were performed. This allowed the precise determination of the coherent and incoherent tune shift and other relevant beam and machine parameters. | ||
TUPB51 |
Gatling Gun Test Stand Instrumentation | |
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| In order to reach the design eRHIC luminosity 50mA of polarized electron current is needed. This is far beyond what the present state-of-the-art polarized electron cathode can deliver. A high average polarized current injector based on the Gatling Gun principle is being designed. This technique will employ multiple cathodes and combine their multiple bunched beams along the same axis. A proof-of-principle test bench will be constructed that includes a 220 keV Gatling Gun, beam combiner, diagnostics station, and collector. The challenges for the instrumentation systems and the beam diagnostics that will measure current, profile, position, and halo will be described. | ||
TUPB52 |
Optical Diagnostic System for the Photon Factory Storage Ring | |
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| Visible synchrotron radiations emitted from two different bending magnets have been used for the optical beam diagnostics at the Photon Factory storage ring. One of these radiations is relayed to an optical hutch where the focusing system and double-slit interferometers are installed, and utilized for the constant monitoring of the transverse beam profile and beam size. The other radiation is transferred to another hutch equipped with the fast-gated camera and streak camera in order to measure the turn-by-turn beam profile, injected beam oscillation, bunch length, and so on. An overview of these optical diagnostic systems as well as some recent results obtained with them will be given in this paper. | ||
TUPB53 |
Abort Diagnostics and Analysis during KEKB Operation | |
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| KEKB has stopped since June 2010 for upgrading the luminosity 40 times, i.e. SuperKEKB. During the operation of 11 years, a pair of controlled beam abort systems worked more than 10000 times to protect the hardware components of KEKB accelerator and the detector against the high intensity beams of LER and HER. Optimization of the abort trigger was necessary to balance efficient operation with the safety of the hardware. Therefore, we analyzed one-by-one all of the aborts, and continually adjusted the abort system. The diagnostic system was based on a high-sampling-rate data logger that recorded beam currents, RF signals and beam loss monitor signals. The beam oscillation signals, vacuum pressure and detector dose rate were also examined. This paper describes the typical abort causes, optimizations of abort levels, and abort statistics over approximately eight years after having arrived at high beam current operation. | ||
TUPB54 |
The Radioactive Beam Diagnostics at LNS - INFN | |
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| At LNS - INFN Catania, two complementary facilities for Radioactive Ion Beams have been developed in recent years. They exploit the two techniques known as Isotope Separation On Line (ISOL) and In Flight Fragmentation, with a primary beam accelerated by means of the LNS Superconducting Cyclotron. EXCYT makes use of the ISOL technique to produce the radioactive beams, with an energy up to 7 AMeV. FRIBs uses the In-Flight technique, with an energy up to 60 AMeV. The intensity is well below to the levels of the standard stable beams, being tipically below 106 pps. The standard beam diagnostics cannot be used, because of the low signal to noise ratio. An efficient beam diagnostics has been therefore developed and installed, well suited for our low intensity radioactive beams. It permits an accurate check in real time of the beam, such as the profiles, the intensity and the isotope identification along the beam lines, thus allowing the optimization of the transmission until to the experimental halls. The devices are based on nuclear particle detectors, in particular on position sensitive silicon detectors (PSSD), germanium detectors, scintillators and scintillating optical fibres. | ||
TUPB55 |
S-band Timing Diagnostic at the LCLS | |
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Funding: DOE Timing and synchronization at the LCLS is a multiple tiered process with various hardware and software systems, which are functionally independent. This autonomy has resulted in timing errors observed by LCLS users. Coherent laser timing jumps have occurred during cycles of unlocking-locking the Femtolock box. The software does not monitor the state of the Femtolock and these jumps occur when the laser SPAC (on 476 MHz) rotates the reference phase larger than 350ps (one cycle of 2856 MHz). A diagnostic was developed to accurately measure the time difference between the timing fiducials and the beam-induced signal from the toroids in the LCLS injector. This diagnostic has a timing has 40ps and detects these timing jumps as they occur. |
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TUPB56 |
MicroTCA.4: a New Standard for Diagnostics and Controls | |
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| MTCA.4 was released in Oct 2011 as a new standard based on MicroTCA with extensions for rear IO and precision timing. The MTCA.4 standard was driven by several accelerator labs together with industrial partners within the PICMG. It provides a higher degree of modularization compared to other crate systems. Complex designs with FPGA interfaces to PCIe on the front side of a crate can be interfaced by application specific signal conditioning or processing on the rear side. Even high performance RF front-ends could be implemented on a rear module. And the new standard defines precision clock and trigger distribution within a shelf. Furthermore, full remote management on the crate and slot level is available. Diagnostic electronics require a clean environment for sensitive signal processing and high speed data transfers to cope with increasing ADC sampling rates and fast feedbacks. High quality and high performance of analog signal processing was recently demonstrated. The highlights of the new MTCA.4 standard as well as experience and results with the first systems in the field will be described. | ||
TUPB57 |
Extreme Light Infrastructure - Research and Technology on New Short Pulse Intense Laser driven X-ray Sources | |
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Funding: Czech Science Foundation (Project No. P205/11/1165), the Czech Republic's Ministry of Education, Youth and Sports to ELI-Beamlines (CZ.1.05/1.1.00/483/02.0061) and OPVK CZ.1.07/2.3.00/20.0087). We will be giving an overview on the development of the 'ELI-Beamline facility', which will be a high-energy, repetition-rate laser pillar of the ELI (Extreme Light Infrastructure) project. It will be an international facility for both academic and applied research, slated to provide user capability since the beginning of 2016. The main purpose of the facility is the generation and applications of laser driven high-brightness X-ray sources and accelerated particles (electrons, protons and ions). The laser system will be delivering pulses with length ranging between 10 and 150 fs and will provide high-energy Petawatt and 10-PW peak powers. We will concentrate on the development of short photon wavelength (20 eV-100 keV) laser driven sources and their practical implementation. The sources are either based on direct interaction of the laser beam with a gaseous or solid target or will first accelerate electrons which then will interact with laser produced wigglers or directly injected into undulators. The main planned short pulse laser driven x-ray sources and their parameters will be presented together with requirements on the relevant beam detectors. |
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TUPB58 |
Design Status of the Diagnostic System for the RISP Driver Linac | |
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| Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of diagnostic system is especially high for the RISP commissioning and operation. Design of diagnostic devices such as beam profile monitors, beam current monitors (BCM), Faraday cups, emittance scanners, bunch shape monitors (BSM) are under way. In this paper, we summarize in detail current status of the RISP beam instrumentation. | ||
TUPB59 |
Beam Diagnostics of Injector Test Facility for PAL XFEL | |
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Funding: Supported by the Ministry of Education, Science and Technology in Korea. We are constructing an injector test facility (ITF) for the PAL XFEL. The target of the facility is to demonstrate an emittance of < 0.5 mm mrad (projected, normalized rms) at the beam charge of 200 pC with small energy spread and high stablities. By collaborating with the RADIABEAM Technologies*, we have developed beam diagnostics with enough precision and reliability to provide beam information including beam energy, energy spread, charge, profile, position, and bunch length. Resolutions of the beam-size and position measurements will be 17.5 um (rms, for OTR screens) and < 10 um (rms) respectively. A S-band transverse deflecting cavity will be used for measuring the bunch length with resolution down to 10 fs. In this article we report on current status of the PAL-XFEL injector test facility with emphases on its beam diagnostics. * http://www.radiabeam.com/ |
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TUPB60 |
Beam Diagnostics of Central Japan Synchrotron Radiation Research Facility Accelerator Complex | |
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| A new synchrotron radiation facility, Central Japan Synchrotron Radiation Research Facility is built in Aichi area. The light source accelerator complex consists of a 1.2 GeV compact electron storage ring and a full energy injector for top-up operation. The key equipments of the accelerator are four 5 T superconductive bending magnets. Although the acceleration energy of the storage ring is relatively low, synchrotron radiation from the superconductive bending magnet reaches hard X-ray region and can be provided for more than 10 beamlines. Construction of the facility started in 2010 and finished in Apr. 2012. Commissioning of the accelerator complex started in Mar. 2012. We adapted a turn-by-turn beam position monitoring system based on a digital oscilloscope developed at the UVSOR. In the presentation, we report on details of beam diagnostics conducted during the commissioning. | ||
TUPB61 |
First Experience with the LHC Beam Gas Ionisation Monitor | |
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| The Beam Gas Ionisation Monitors (BGI) are used to continuously measure the beam size at the LHC. This paper describes the detectors and their operation and discusses the issues encountered during the commissioning. It also discusses the various calibration procedures used to correct for non-uniformity of Multi-Channel plates and to correct the beam size for effects affecting the electron trajectory after ionisation. | ||
TUPB62 |
Transverse Emittance Measurement using Slit-Grid | |
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There are several ways to measure the beam transverse emittance. In this paper, the slit-grid emittance measurement device was proposed. The slit-grid is a one dimensional emittance measurement device. During the measurement, the slit, driven by the stepper motor is moved stepwise across the beam, and then the signal induced on the grid will be stored in the computer for further analysis. Because slit-grid is one dimensional device, two sets of this device are needed for transverse measurement. In this paper, we introduce the design, parameters, data acquisition and analysis for this measurement. Especially the software integration is given in this paper. The software development for emittance front-end control and data analysis is based on the labview language. The slit-grid device was tested at the 320kV high voltage platform in Lanzhou. The tested results were also presented in this paper.
beam transverse emittance,slit-grid |
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TUPB63 |
Development of Turn-by-turn Beam Diagnostic System using Undulator Radiation | |
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| At the diagnostic beamline II (BL05SS) of the SPring-8 storage ring, a turn-by-turn beam diagnostic system using undulator radiation has been developed to observe fast phenomena such as stored beam oscillations during the top-up injections, blowups of beam size and energy spread coming from the instabilities of a high current single bunch and so on. The fast diagnostic system observes a spatial profile of the undulator radiation on a selected harmonic number. Especially, the higher harmonic radiations than the 10th-order are sensitive to the energy spread. A fluorescence screen (YAG:Ce) with afterglow of several tens of nano-second converts the radiation profile into visible light image. The imaging optics makes the horizontal and vertical profiles as two line images by one-dimensional focusing using cylindrical lenses. A fast-gated CCD camera with image intensifier simultaneously captures the two line images. The kinetics readout mode of the fast CCD camera is used to register the spatial profiles of several tens of turns in one flame. The principle and experimental setup of the turn-by-turn diagnostic system, and examples of beam observations will be presented. | ||
TUPB64 |
Methods to Reduce the System Error for High Power MSSW Emittance | |
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| Recently a new Multi-Slit Single-Wire (MSSW) type high power beam emittance meter named as HIBEMU-5 has developed in Peking University (PKU). Compared to previous MSSW devices, HIBEMU-5 greatly reduced the system error from 16.4% to 3.7% by specific designs to solve the incomplete short-slit sampling and fixed slit-wire distance. The problems of previous PKU devices are analyzed in part one. In part two, we describe the specific updating methods to solve its short-slit disadvantage by re-designing a longer-slit board with sufficient cooling, detail the mechanical scheme of changing the slit-wire distance for different beam divergence. The commissioning results given at part three prove that this new long slits design is successful to complete the beam sampling without being distorted by high power H+ beam. And the movable wire cup is able to locate the best measurement position for different beam focusing | ||
TUPB65 |
Transverse-acceptance Measurement System for the JAEA AVF Cyclotron | |
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| We are developing an acceptance measurement system to evaluate transverse phase-space matching of the emittance of an injection beam to the acceptance of the AVF cyclotron. The system is composed of a phase-space collimator in the low energy section and a beam intensity monitor in the high energy section. The phase-space collimator, which consists of two pairs of slits, allows very small-emittance beams to be injected into the cyclotron by limiting position and divergence angle of the beam from an ion source. The beam intensity monitor is used to obtain the ratio of beam intensity at the collimator to that at the monitor. In acceptance measurement, the small-emittance beams at various positions in a transverse phase-plane are injected to determine the distribution of relative transmission in the phase plane. In preliminary tests, only a part of acceptance was able to be measured because the injection-beam emittance from ion sources does not cover the whole acceptance. To expand the measurement area, a steering magnet has been added in the system. The magnet scans the injection beam in phase planes in synchronization with the acceptance measurement to simulate the large emittance. | ||
TUPB66 |
A Beam Tail Monitoring System of a High Intensity Beam to the Main Ring of J-PARC | |
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| We have established a real-time beam-tail monitoring system using long air ionization chambers (AICs) and collimators of the beam transport line to the main ring of J-PARC. The collimators remove the beam tail components outside the emittance of 54pi mm mrad for horizontal and 60pi mm mrad for vertical, and the AICs identify the beam loss power at the collimators. The intentional beam losses have been used to calibrate the AICs. The output response showed good linearity up to the intensity of 8.4·1011/batch, which amounts to 1% of the designed beam intensity of 8·1013/batch, and the estimated error was ±7% which includes a dependence of beam loss points on the collimators and the shot-by-shot beam fluctuations. The calibration procedures and the performances of the system will be described. | ||
TUPB67 |
Test Measurements of Beam Profile Monitor at HIRFL-RIBLL2 | |
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| The beam intensity supplied by HIRF-CSR has a wide range, high-intensity primary beams and low intensity fragment-beams in connection with the slow extraction and the fast beam-extraction from the synchrotron CSRm. The detector (CG) has been developed for the beam profile monitoring at radioactive beam line HIRFL-CSR. The front-end electronics are based on CPLD controlled sample-and-hold circuits and multiplexer. Remote control is used to tune the detector sensitivity by setting the gas pressure in the detector's cell, the bias voltage of the anode and the integration time. The test measurements results are presented in this paper. Keywords: beam profile monitor; current grids; multiplexer; HIRFL CSR; | ||
TUPB68 |
A new Multi-strip Ionization Chamber used as On-line Beam Profile Monitor at HIRFL-CSR | |
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| The beam extracted from CSRm is mainly used for heavy-ion tumor therapy and physics experiments with stable and radioactive ions. A position sensitive detector is usually implemented to monitor the primary beam online in the nuclear experiments. Meanwhile, the detector should be thin enough to reduce the influence of energy spread and beam purity. This paper describes the developing and building a new detector with position resolution better than 0.5mm (FWHM) and using metallic-membrane plating technology for sharp reducing electrode's thickness of detector. The sensitive area of the detector is (100×100)mm2, with 1mm strip pitch. The anodes, cathode and the sealed windows are all made by 2μm thick Mylar layer on which a 0.1μm thick film of aluminum has been plated. Total thickness of the detector is about 12μm. | ||
TUPB69 |
Numerical Analysis on the Gain-reduction Characteristics of Multi-wire Proportional Chambers | |
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| Several MWPC (Multi-Wire Proportional Chamber) monitors are installed to diagnosis the beam profiles in the high-energy beam transport at HIMAC (Heavy Ion Medical Accelerator in Chiba) synchrotrons. When the intensity of the incident beams are much high, the gain reduction of the output signal from the MWPC monitor occurs due to the space charge effect of positive ions around the anode wires. The gain reduction is expected to be improved by changing geometric parameters, such as anode radius and distance between electrodes. In order to investigate the gain-reduction characteristics for different geometric parameters, we performed numerical simulation using a numerical code. The numerical code was developed using a two-dimensional drift-diffusion model to evaluate the gas gain including the reduction effect caused by the space charge effect of the moving positive ions. We investigate the gain-reduction rate for several parameters of the anode distance when changing the beam intensity. From these results, we discuss desirable distances between the anode wires to improve the gain reduction. | ||
TUPB70 |
The ATF2 Multi-OTR System: Studies and Design Improvements | |
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Funding: Funding Agency: FPA2010-21456-C02-01 Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-Optical Transition Radiation system made of four stations has been installed in the extraction line of ATF2 and has been fully operational since September 2011. The system is being used routinely for beam size and emittance measurements as well as for coupling correction and energy spread measurements. In this paper we present the beam sizes and emittance measurements performed during 2012 runs as well as a detailed study of the experimental single-shot automated coupling correction and the comparison with the simulations. Wakefields problems experimented with the simultaneous measurement has been studied and will be solved by new target holders that will be installed in the next Fall 2012 run. |
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TUPB71 |
A New Low Intensity Beam-profile Monitor for SPIRAL2 | |
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In order to obtain profiles of SPIRAL 2 ion beams, several beam-profile monitors are presently being developed at GANIL. One of them is a low-intensity beam-profile monitor that works as a secondary electron detector. This Emission-Foil Monitor (EFM) will be used in the radioactive beam lines of SPIRAL2 and in the experimental rooms of this new facility. The ions produce secondary electrons when they are stopped in an aluminium emissive foil. The electrons are then guided in an electric field placed parallel to a magnetic field in a double-stage microchannel plate (MCP). A 2D pixelated pad plane placed below the MCP is then used to collect the signals. The magnetic field created by permanent magnets in a closed magnetic circuit configuration permits the beam-profile reconstruction to be achieved with good resolution. The EFM can visualize beam-profile intensities between only a few pps to as much as 10 9 pps and with energies as low as several keV. This profiler has been studied since 2011 and will be manufactured in 2013. For the signal acquisition, a new dedicated electronics system will be employed. Recent results of this monitor and the electronics will be presented here.
*The beam profile monitor for SPIRAL2, DIPAC09 **THE BEAM PROFILE MONITORS FOR SPIRAL 2 RIB AND EXPERIMENTAL ROOMS, DITANET workshop 2009. ***A. Drouart at al, Nucl. Instr. and Meth. A 579(2007). |
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TUPB72 |
Injected Beam Profile Measurement during Top-Up Operation | |
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| A coronagraph-like apparatus was constructed on the optical diagnostic beamline on the storage ring to observe the injected beam during top-up operations. An image was created on an intensified CCD that can be gated on a single bunch or on a bunch train for a stronger signal. The bright central stored beam was obscured so the comparatively faint injected beam could be observed. The injected beam comes in at a large enough offset so that it was clearly visible above any diffraction or beam halo signals. The beam profile measured was in good agreement with the observations made of the injected beam only using a telescope apparatus. The measurements were made during user beam in top-up operation mode and can be used to optimise the injection process. | ||
TUPB73 |
Development of a Beam Profile Monitor using Nitrogen-Molecular Jet for Intense Beams | |
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Funding: This work was supported by MEXT/JSPS KAKENHI Grant Number of 24310079 (Grant-in-Aid for Scientific Research(B)). A non-destructive beam profile monitor using a sheeted jet beam of nitrogen molecular as a target has been developed for intense ion beams. The pressure of the sheeted molecular beam was 5 x 10-4 Pa at the beam collision point. A light emitted from excited nitrogen by an ion beam collision is measured by a high sensitive camera with a radiation resistant image intensifier. Verification of such a principle was already demonstrated with low-energy ion beams[1]. In this paper, some actual designs for intense beams of the J-PARC MR will be discussed mainly as bellow, intensity upgrade of the jet beam production, configuration of the detection chamber and its apparatus placed beam collision point, and the optical system for the light detection. *[1] Y. Hashimoto, et al., Proc. of IPAC'10, Kyoto, Japan, p.987-989. |
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TUPB74 |
Diamond Mirrors for the SuperKEKB Synchtron Radiation Monitor | |
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| The SuperKEKB accelerator, a 40x luminosity upgrade to the KEKB accelerator, will be a high-current, low-emittance double ring collider. The beryllium primary extraction mirrors used for the synchrotron radiation monitors at KEKB suffered from heat distortion due to incident synchrotron radiation, leading to systematic changes in magnification with beam current and necessitating continuous monitoring and compensation of such distortions in order to correctly measure the beam sizes. The heat loads on the extraction mirrors will be higher at SuperKEKB, with heat-induced magnification changes up to 40% expected if the same mirrors were used as at KEKB. We are working on a design based on mirrors made of quasi-monocrystalline diamond, which has much higher heat conductance and a lower thermal expansion coefficient than beryllium. With such mirrors it is targeted to reduce the beam current-dependent magnification effects to the level of a few percent at SuperKEKB. Measurements of heat-induced deformations on fabricated prototype mirrors will be presented, along with comparisons with the results of numerical simulations. | ||
TUPB75 |
Design and Construction of SEM for Continues 200keV Electrostatic Accelerator | |
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| Beam profile and position monitoring at continues beams aren't possible by electromagnetic based instruments such as Pick Up, by this regard, design and construction of SEM has done for 200 keV electrostatic machines which can be classified into mechanic and electronic sections. At mechanical section the vacuum chamber with 3 feed-through which each one has 32 pins was constructed then grids with 16 copper wire with length of 10 cm and 80 μm diameter at each vertical and horizontal direction considered. The produced signals amplified and then digitized by ADC and transferred by ATMEGA32 ports to PC which set by GUI (MATLAB) as data analyzer. Induced profile at quartz glass which is placed at the end of beam tube was considered as bench mark source. The electrical results were compared with the result of quartz as practical method and CST as simulation. high accuracy and precision deduced which is presented at this article. | ||
TUPB76 |
Infra Undulator Screen Diagnostics for FERMI@Elettra FEL | |
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| The FERMI @Elettra seeded FEL has demanding requirements in terms of intra-undulator diagnostics. An advanced multi-purpose screen system has been developed and installed on the FEL1 and FEL2 intra-undulator sections. These diagnostics have been designed also to allow both electron beam transverse size measurement and FEL radiation spatial distribution measurements. A series of important constrains in the design such as COTR suppression, seed laser suppression, FEL wavelength range and minimization of ionizing radiations has led to new design concepts. The paper describes the design, the features and the performances obtained with the FERMI intra-undulator screen system. | ||
TUPB77 |
Measurement of the Frequency Spectrum on the Beam Profile Controlled by RF Kicker | |
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| The frequency spectrum on the beam profile was measured at the compact superconducting storage ring of Ritsumeikan University. The radiation detector was used an avalanche photodiode module with a high frequency response of 1 GHz for the visible ray. Signals from the detector were transferred to a spectrum analyzer. The beam profile was magnified strongly by a conventional profile monitor system. We scanned the beam profile in vertical direction by shifting the detector. The distribution of peak intensity as a function of the position on beam profile was obtained. | ||
TUPB78 |
Flying Wire Beam Profile Monitors at the J-PARC MR | |
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| Transverse beam profiles have been measured using flying wire monitors at the main ring of the Japan Proton Accelerator Research Complex. The wire target should be thin and the wire scan has to be fast for the precise profile measurement. Otherwise the beam distribution would be disturbed and the measured profile would not be accurate. We use carbon fibers of 7 μm in diameter and the scan speed of 10 m/s. The wire is attached with an aluminum flame of 140 mm of the rotation radius and rotated with a DC servomotor. A potentiometer is attached to the wire flame and the angle readout is used for the feedback of the servomotor and the wire position measurement. The secondary particles from the beam-wire scattering are measured with a scintillation counter. Beam profiles are reconstructed by making the scatter plot of the scintillator signal and wire position. Both horizontal and vertical flying wire monitors have been used for the beam commissioning. We have successfully measured the beam profile of up to 1.2×1013 protons per bunch. | ||
TUPB79 |
Use of Gafchromic Films to Measure the Transverse Intensity Distribution of a Large-Area Ion Beam | |
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| In the TIARA AVF cyclotron facility of JAEA, it is necessary to evaluate the cross-sectional area and uniformity of a large-area uniform ion beam formed by multipole magnets both precisely and handily. A technique has, therefore, been developed to measure the two-dimensional transverse intensity distribution of the ion beam using Gafchromic radiochromic films (Ashland Inc.). In order to show available fluence ranges of the film, the coloring response of the Gafchromic films irradiated with several species of ion beams is investigated as a change in the optical density of the film. It has been found that the optical density increases linearly with the fluence, whose range is practical for materials and biological research. Thus, the relative transverse intensity distribution of ion beams can be measured using the film. Furthermore, the intensity distribution determined by the Gafchromic film is compared with the area-density distribution of track-etched pores in a polymer film from a microscopic viewpoint. It has been demonstrated that the beam uniformity obtained from the Gafchromic film is equivalent to the relative standard deviation of the microscopic pore distribution. | ||
TUPB80 |
Transverse Profile Monitor for SwissFEL | |
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| In future free electron lasers, electron and photon beam sizes range between 10 um and a few millimeters. For an initial set up of the accelerator, to confirm target parameters for optics and emittance, and to optimize the FEL for different user requests, the transverse profile of these beams has to be determined. A monitor based on a scintillating crystal as well as optical transition radiation (for the electron beam) has been designed for the SwissFEL project. It features a projected pixel size of 7 micrometers, a good resolution over a field of view of 6 mm x 15 mm, a good sensitivity (as required for the low-charge mode of SwissFEL) and a 100 Hz image readout. To test the monitor, it has been installed at the SwissFEL Injector Test Facility, where electron bunches between 10 and 200 pC can be generated. In conjunction with a transverse deflecting cavity, the profile monitor has been used to measure the time-resolved slice emittance of these bunches. | ||
TUPB81 |
Design of the Beam Profile Monitors for the SXFEL Facility | |
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| The Shanghai X-ray Free Electron Laser Facility will begin construction at next year. The linac electron beam energy is 0.84 GeV. Over 50 beam profile monitors with OTR and YaG screen will be installed along the linac and undulators. The profile monitor system design is a challenging task, since the system has to measure transverse electron beam sizes from millimeter down to 40μm scale with a 20μm resolution and 50μm repeat positioning accuracy. This paper describes the design of the mechanical detector , the integrated step-servo motor controlling system, the beam imaging system, as well as the software system. | ||
TUPB82 |
Development of Laser Wire System in the Electron Beam Transport Line of BEPCⅡ | |
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Funding: National Natural Science Foundation of China A Laser Wire system is under development in the electron beam transport line of BEPCⅡ (Beijing Electron Positron Collider Ⅱ). The whole system will be installed in the tunnel of beam transport line in this summer shutdown of the BEPCII. We present recent work on subsystems of Laser Wire in this paper, such as improvement of laser system and construction of gamma detector. Some measurement and test results are also showed. The electron beam profile measurement experiment with Laser Wire will start in the next accelerator run. |
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TUPB83 |
Beam Size and Emittance Measurements in the ALBA Booster | |
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| The synchrotron radiation monitor in the ALBA Booster provides a measurement of the transverse beam size, which is then used to evaluate the emittance evolution along the energy ramp. We find that the beam size measurement is significantly influenced by the Booster closed orbit deviations. This report describes the experimental measurements, and compares them with theoretical expectations. | ||
TUPB84 |
Storage Ring Tune Measurements using High-Speed Optical Photodiodes | |
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| Knowledge of the betatron tunes within a storage ring is important to prevent the creation of instabilities and maximise the lifetime of the stored current within the ring. Typical tune measurements excite the beam and measure the resulting motion over time using electromagnetic pickups. The novel measurement technique presented utilises high-speed MSM photodiodes in a balanced detector set-up to measure the vertical and horizontal betatron tunes. Radiation from a bending magnet consists of both visible light and X-rays. The visible light is separated from the X-rays with an optical chicane and focussed onto a pair of length-matched optical fibers each coupled to an MSM photodiode. The specialised biasing circuit for the photodiodes is constructed in a balanced detector configuration to emphasise any motion in the beam. Signal resulting from beam motion is amplified and digitised for analysis. Using this set-up the tunes for the storage ring at the Australian Synchrotron have been measured and verified with comparison to existing tune measurement technologies. The results from the new optical tune measurement system will be presented and discussed. | ||
TUPB85 |
Spectrum of Bunch-by-Bunch Position Model and Parameter Acquisition Algorithm | |
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| Based on the spectrum of turn-by-turn model for the storage ring, spectrum of bunch-by-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve. | ||
TUPB86 |
An Upgrade for the Bunch Current Measurement System of BEPCⅡ | |
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| Recently, the BCM (Bunch Current Measurement) system is being developed at BEPCⅡ(Beijing Electron-Positron ColliderⅡ). In order to solve the instability problems which frequently happen in the existing system, we have upgraded the DAQ system with new ADC card and new DSP arithmetic in FPGA. In addition, some discussion for the upgrade such as the generality of the arithmetic, easy to change operation mode, noise reduction measurements, and so on, are also presented in this paper. | ||