MOPB50 |
Design and Operation of the LHC's High Intensity Luminosity Monitor | |
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Funding: We acknowledge the US-LARP program that is sponsoring this work and NERSC, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. We have built a high-pressure ionization chamber (BRAN) for the IP1 (ATLAS) and IP5 (CMS) regions of the LHC. This chamber is designed to measure the relative bunch-by-bunch collision rate of the LHC from 1028 cm-2s−1 during beam commissioning all the way up to the expected full luminosity of 1034 cm-2s−1 at 7.0 TeV. These high-pressure ionization chambers measure the intensity of hadronic/electromagnetic showers produced by the forward neutral particles of LHC collisions. They are designed to withstand the high radiation produced by these forward collisions and are currently used in LHC operations. This paper covers the detector's design and performance in measuring both pp and PbPb collisions during LHC operation, including a comparison with the ATLAS and CMS luminosity measurements. The work also includes modeling of the detectors and the ability to predict how the detector will respond to the higher energy and intensity operation of the LHC with different operating modes involving both ions and protons. |
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MOPB51 |
Beam Monitors of NIRS Fast Scanning System for Particle Therapy | |
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| At National Institute of Radiological Sciences, more than 6500 patients have been successfully treated by carbon beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with three-dimensional pencil beam scanning irradiation system. The commissioning of NIRS fast scanning system installed into the new facility was started in September 2010, and the treatment with scanned ion beam was started in May 2011. In the scanning delivery system, beam monitors are some of the most important components. In order to measure and control the dose of each spot, the main and the sub ionization chambers are placed separately as flux monitors. For monitoring of the scanned beam position, a beam position monitor, which is multi-wire proportional chamber, is installed just downstream from the flux monitors. This monitor can output not only the beam position but also the 2D fluence distribution using dynamic fast convolution algorithm. In this paper, the design and the commissioning of these monitors are described. | ||
MOPB52 |
Status and Activities of the SPring-8 Diagnostics Beamlines | |
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| At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress. | ||
MOPB53 |
Hartmann Screen and Wavefront Sensor System for Extracting Mirror at SSRF | |
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| A Be mirror was used to extract visible synchrotron radiation light from bending magnet at SSRF. The surface of mirror was deformed because of X-ray heat. A set of Hartmann Screen Test was used to measure the surface of the mirror. Another equipment named The Shack-Hartmann wavefront sensor system was introduced to get more precision data. The result of two kind of test match each other well. | ||
MOPB54 |
Development of the New Type MLIC with PMMA Plates and Graphite Electrodes | |
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| The MLIC (Multi-Layer Ionization Chamber) that has a lot of ionization chambers stacked in the depth direction is useful a detector for measuring the depth dose distribution. By using the MLIC, the measurement time and the amount of beam for dosimetry are drastically decreased. In HIMAC (Heavy-Ion Medical Accelerator in Chiba), the MLIC has been effectively used for QA (Quality Assurance) measurement of heavy-ion therapeutic beam since 2002. We are developing a new type MLIC that has electrodes made of graphite on the surface of the polymethyl-methacrylate (PMMA) plates for particle therapy. The purpose is to obtain the equivalent measurement results of depth dose distribution in water. We will report on the progress of development. | ||
MOPB55 |
Electron Cloud Measurements using Shielded Pickups 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 storage ring was originally a positron/electron collider with beam energies ranging from 2 to 5 GeV. In 2008 it was reconfigured as the Cornell Electron Storage Ring Test Accelerator (CesrTA). An important part of the research at CesrTA is the study of the growth, decay and mitigation of electron clouds. Electron Cloud (EC) densities can be measured with a Shielded Pickup (SPU), where cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The signals produced by SPU have proved to be very useful in measuring the mitigating effect of different vacuum chamber surfaces - including differences in quantum efficiency as well as secondary and elastic yield. This has been accomplished through the careful comparison of observed signals with the output of the EC simulation code ECLOUD. We present example comparisons of data and simulation that show the effect of different surfaces as well as beam conditioning effects. In addition, some data has been acquired using a solenoid to produce a longitudinal magnetic field at the SPU. We will present our current understanding of the effect of a longitudinal magnetic field on SPU signals. |
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MOPB56 |
Electron Cloud Measurements Using a Time Resolved Retarding Field Analyzer at CesrTA | |
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Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, the US Department of Energy DE-FC02-08ER41538, DE-SC0006505 and US-Japan funding. The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV. An area of research at CesrTA is the study of the growth, decay and mitigation of electron clouds in the storage ring. With a Retarding Field Analyzer (RFA), cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The electrons are captured by several collectors, so that the electron flux can be measured vs. horizontal position. Up to now, we have integrated the collector currents to provide DC measurements. We have recently constructed a new Time Resolved RFA, where the collector currents can be observed on the time scale of the bunch train in the storage ring. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements at CesrTA. |
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MOPB57 |
Overview of Beam Instrumentation and Beam Tuning Methods of RIKEN RI Beam Factory | |
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| RIKEN RI Beam Factory (RIBF) was constructed as the first of the next-generation radioactive-beam facilities aiming at investigating vast unknown fields of unstable nuclei. In order to obtain the world-most intense heavy-ion beams, we have employed, taking into account cost effectiveness, a multistage acceleration scheme including 4 ring cyclotrons. We have already obtained 1 pμA, 0.42 pμA, and 22 pnA beams for 18O, 48Ca and 124Xe ions, respectively. The present performance has been obtained by using very conventional beam instruments such as Faraday cups, wire scanners and so on. Beam instruments used in RIBF are briefly summarized putting emphasis on beam tuning methods using them. In addition, limitations of these conventional devices and possible upgrade of beam instruments are discussed for further intensity upgrades and more stable operations of RIBF. | ||
MOPB58 |
Beam Quality Ensuring Instruments at the Gunma University Heavy-ion Medical Center | |
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| Since the carbon beam based cancer therapy started at the Gunma University Heavy-ion Medical Center in the year 2010, the total number of treated patients increased to 306 by the end of fiscal 2011. This year, already 82 patients have been treated. In order to control the medical beam qualities, i.e., position, size and intensity of the beam, monitoring devices were mounted on the high-energy beam transport line. The beam position and size can be measured and tuned with a screen monitor, which consists of a fluorescent screen and a CCD camera. Just before starting the treatment, the operators check for a proper beam position by strip-line monitor measurements placed close to the iso center. The irradiation dose is controlled using two secondary electron emission monitors placed before the wobbling magnets. This dose monitor is helpful for high fluence of the beam because it's less affected by the recombination effect. In the conference, we would like to report on details of each monitoring device. | ||
MOPB59 |
ADS InjectorⅡ Beam Diagnostics | |
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| A 10 mA/50 MeV superconducting proton linac as the demo of the Accelerator-Driven System (ADS) driver is designing and constructing in China. One of the 10 MeV lines, called injectorⅡ, is fabricating at the Institute of Modern Physics, Chinese Academy of Sciences. It consists of ECR source, LEBT, 2.5 MeV RFQ, MEBT and superconducting structure from 2.5 MeV to 10 MeV. In this paper the diagnostics after the RFQ and to the end of the 10 MeV will be introduced. Some of the measurements in the lab will be described also. | ||
MOPB60 |
Beam Diagnostics for AREAL RF Photogun Linac | |
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| Advanced Research Electron Accelerator Laboratory (AREAL) based on photocathode RF gun is under construction at CANDLE. The basic approach to the new facility is the photocathode S-band RF electron gun followed by two 1 m long S-band travelling wave accelerating sections. Linac will operate in single and multibunch modes with final beam energy up to 20 MeV and the bunch charge 10 - 200 pC. In this paper the main approaches and characteristics of transverse and longitudinal beam diagnostics are presented. The diagnostics included beam momentum, charge, transverse emittance and bunch length measurements for two operation modes. | ||
MOPB61 |
The Status of Turkish Accelerator and Radiation Laboratory in Ankara (TARLA)* | |
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Funding: Work supported by Turkish State Planning Organization (Grant No: DPT2006K-120470) Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) project has been supported by State Planning Organization (SPO) of Turkey since 2006 as a first step of the national Turkish Accelerator Center (TAC) project. TARLA facility, which is essentially proposed to generate oscillator mode FEL in 2-250 microns wavelengths range, will consist of totally normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam between 15-40 MeV energies, and two different optical cavity systems with different undulator magnets with the periods of 25 mm and 90 mm. However continuous wave (CW) electron beam provided by TARLA accelerator is convenient for many other applications. Therefore additional Bremsstrahlung laboratory is also proposed at TARLA. In this study we present the current status of TARLA, time scale for commissioning process in addition to the operation process of thermionic gun. *On behalf of TARLA Collaboration, www.tarla-fel.org |
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MOPB63 |
Emittance Measurement using X-ray Profile Monitor at KEK-ATF | |
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| The X-ray profile monitor consists of two Fresnel zone plates and X-ray CCD camera. The synchrotron radiation from the bending magnet is monochromatized by a crystal monochromator. The design resolution of the selected wavelength 3.8nm is sufficiently small for the emittance measurement of the KEK-ATF. However, the measurement result at the early stage was affected to the mechanical vibration. This paper describes the improvement of the resolution and the measurement results. | ||
MOPB64 |
Emittance Measurement for BEPCII Linac | |
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| BEPCII is an upgrading project of the Beijing Electron-Positron Collider. Recent efforts have been focussed on improving beam transmission between linac and storage ring. Emittance measurements using four wire scanners. The result of measurement and some discussion will be presented. | ||
MOPB65 |
Measurement of Sub-picosecond Bunch Length with the Interferometry from Double Diffraction Radiation Target | |
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Funding: This work was supported by the joint Russian-Chinese grant (RFBR N 110291177 and NSFC N 11111120065) and partially by the Program of Russian MES 'Nauka' and Chinese NSFC grant N 11175240. Reliable and precise methods for non-invasive diagnostics of sub-picosecond electron bunches are required for new accelerator facilities (FEL, LWFA, et al.). Measurements of spectral characteristics of coherent radiation generated by such bunches using interferometer allow to determine a bunch length [1]. The interference pattern obtained by two diffraction radiation (DR) beams from two shifted plates (double DR target) may be used instead an interferometer [2]. Recently the coherent DR interferometry scheme at the SINAP accelerator facility was established [3]. Here we report the results of comparing the first measurement from such a technique with the measurement from Michelson interferometer. The parameters of fs linac are described in [4]. The DR target was consisted of two plates made from aluminum foil. The pyroelectric detector SPI-D-62 was used. The analysis of results from two techniques gives the same estimated bunch length about 660 fs (0.2 mm), which confirms the ability of the proposed technique for non-invasive bunch length measurements in the sub-picosecond range without a complicated scheme like Michelson interferometer or similar. 1. Murokh A.et al.,NIMA 410(1998)452 2. Potylitsyn A.P.,NIMB 227(2005)191 3. Shevelev M. et al.,Journal of Physics: Conference Series 357(2012) 4. Lin X.et al., Chin. Phys. Lett.27,4(2010)044101 |
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MOPB66 |
Optimization of the Interferometry Beam Size Monitor in PLS-II | |
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| Pohang Light Source-II (PLS-II) is recently upgraded to 3 GeV and the circumference, beam current, emittance of PLS-II storage ring are 281.82 m, 100 mA and 5.7 nm-rad, respectively. The storage ring includes an interferometry beam size monitor system in 2B beam line. It consists of the quadrature slit, lens, 650 nm wave-length filter and CCD camera. We will present the measurement results and the issues to optimize the beam size monitor system in the beam line. | ||
MOPB67 |
Development of Offner Relay Optical System for OTR Monitor at 3-50 Beam Transport Line of J-PARC | |
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| An extremely wide aperture relay optical system based on Offner system has been designed and constracted for OTR monitor at 3-50 beam transport line of J-PARC. Diagnostics for beam profile and halo are very important to optimize injection beam from RCS to MR in J-PARC. For this purpose, an OTR monitor is planed to install for an observation of image of the beam and halo after the beam collimators. Since opening of OTR is very wide due to small Gamma; 3.2, extremely wide aperture (500mrad) optics will necessary to extract OTR from file target. We designed Offner type relay optics for the effective extraction of OTR having F=0.83. The clear aperture will cover 100 x 100mm aria on the target screen. Results of optical testing and design of OTR monitor will present in this paper. | ||
MOPB68 |
Development of Profile Monitor System for High Intense Spallation Neutron Source | |
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| At the JSNS in J-PARC, a mercury target is employed as the neutron production target. It is well known that the damage on the mercury target is promotional to the 4th power of the peak current density of the primary proton beam on the target. For the high intense neutron source, the profile on the target is important to drive the neutron source with the continuously observation of the profile. We have developed to Multi Wire Profile Monitor System (MWPM). During beam operation, when the abnormally of the beam is found, the beam is cut out by the Machine Protection System (MPS). For the measurement of the two dimension observation on the target, we have developed the system based on the residual radiation measurement by using an imaging plate (IP), It is found that the both result by the MWPM and IP shows good agreement. | ||
MOPB69 |
Development of Four Mirror Pulsed Laser Wire System for ATF-KEK Damping Ring | |
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Funding: Quantum Beam Technology Program of Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). Production and handling of a low emittance beam is one of the key technologies for linear colliders. The Accelerator Test Facility (ATF) was constructed at KEK to study low emittance beam physics and to develop the technologies associated with it. In ATF damping ring, the vertical beam size is less than 10 μm. To measure it precisely, a thin and intense laser beam is required. We utilize a pulsed four mirror optical cavity based on IR laser oscillator to fulfill this requirement. With pulsed green laser oscillator, the beam waist will reduce by factor of 2. Therefore, with green laser oscillator, effective electron-photon collision can be observed. Minimum beam waist is obtained in sagittal plane. Special type of mirror alignment scheme is used to make a compact four mirror optical cavity. With Pulsed laser oscillator the electron beam scanning is very fast as compare to CW Laser wire system. Profile of electron beam can be measured in vertical, horizontal and longitudinal direction within a few second. We report the design studies of such compact resonator and scheme to obtain laser beam size less than 6μm in rms. |
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MOPB70 |
The Synchrotron Radiation Diagnostic Beam line of SSRF | |
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| The synchrotron radiation photon beam line has been operated since 2009 at Shanghai Synchrotron Radiation Facility. There are two diagnostic beam lines of the storage ring behind bending magnet, which is employed conventional X-ray and visible imaging techniques. A synchrotron radiation (SR) interferometer using visible light region in order to measure the small transverse electron beam size (about 22μm); low emittance and a low coupling. A small off-axis mirror is set for the convenience of the observation. Wave front testing is used for interferometer to calibrate the deformation effect of optical components. An X-ray pin-hole camera is also employed in the diagnostics beamline of the ring to characterize beam. Typically the point spread function of the X-ray pinhole camera is calculated via analytical or numerical method. Those two methods check each other. As a result, the measurement with SR system has quite enough resolution of itself even though the absolute beam size acquired. The existed system suffers with dynamic problem for beam physics studies. It has been measured 2.8nm.rad in small emittance mode at SSRF. | ||
MOPB72 |
First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line | |
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Funding: Kakenhi The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented. |
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MOPB73 |
Beam Size and Intensity Diagnostics for a SRF Photoelectron Injector | |
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Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin A high brightness photoelectron injector must be developed as a part of the BERLinPro program. The injector is designed to produce an electron beam with 100 mA average current and a normalized emittance of 1 mm*mrad. The project will be realized in two stages. First with a Pb cathode in a SRF gun, work ongoing, followed by a normal conducting CsK2Sb cathode capable of generating high current beams. In the first stage we have measured the fundamental beam parameters bunch charge, beam energy and energy spread with a special focus on the measurement of the transverse beam profiles. We also discuss our plans for the beam characterization at high currents. |
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MOPB74 |
Beam Measurement with Synchrotron Radiation for BEPCII Storage Ring | |
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| The detail of Synchrotron Light Monitor for BEPCII storage ring is introduced. The Synchrotron Light Monitor measures both transverse beam profiles and longitudinal bunch length. Transverse profiles are measured by visible light imaging and spatial interferometer, and longitudinal bunch length is measured by streak cemera and intensity interferometer. | ||
MOPB75 |
Real-time Beam Profile Measurement System using Fluorescent Screens | |
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| In the TIARA AVF cyclotron facility of JAEA, we are developing an irradiation technique of a large-area uniform ion beam formed by nonlinear focusing using multipole magnets. It is indispensable to perform beam tuning and evaluation of the beam quality at the same time for efficient operation. Therefore, we developed a real-time beam profile measurement system composed of two CCD cameras, fluorescent screens, and an image analysis program based on LabVIEW. In order to measure the transverse intensity distribution of the beam through the luminance map converted from a camera image, the characteristics of fluorescent screens, DRZ (Gd2O2S:Tb) and AF995R (Al2O3:Cr), were investigated using several species of ion beams. It was found that the light yield from the DRZ-HIGH screen irradiated with 10 MeV H+ beam was increased linearly with the particle fluence rate from 5×107 to 5×108 [cm-2･s−1] and that the relative transverse intensity distribution could be obtained from the fluorescence in real time. It was also confirmed that the intensity distribution measured in this system agreed well with the relative intensity distribution obtained with a Gafchromic radiochromic film. | ||
MOPB76 |
Evaluation of a Fluorescent Screen with a CCD System for Quality Assurance in Heavy-Ion Beam Scanning Irradiation System | |
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| The precise heavy-ion therapy such as the scanning irradiation system necessitates the precise quality assurance (QA) procedures to verify the performance of therapeutic scanned ion beams. To evaluate the uniformity of the 2D field, radiographic film is used due to its high spatial resolution and suit for the measurements of the integral dose. However, this technique is time consuming. Thus, we developed the QA tool with high spatial resolution to verify accuracy of the lateral size, position and uniformity of scanned ion beams in clinical application at the HIMAC, which we called the QA-SCN. The QA-SCN consists of a fluorescent screen, a CCD camera, a mirror, camera controllers and a dark box to protect against surrounding light. In this paper, to evaluate the performance of the QA-SCN, we compared the results obtained by using it with the measurements by radiographic film performed in the same experimental conditions. Also, we verified several types of corrections about errors, e.g. background, vignetting, to distort the measurement results. As a result, we confirmed that the QA-SCN can be used as the system for QA procedures of therapeutic scanned ion beams. | ||
MOPB77 |
Adjustable Optics for a Non-destructive Beam Profile Monitor based on Scintillation of Residual Gas | |
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| The scintillation profile monitor (SPM) is being developed at COSY in addition to the existing ionisation profile monitor (IPM). Contrary to the IPM it does not require in-vacuum components, making it a robust and inexpensive instrument. The SPM is suitable for high intensity operation rather than operation with low intensity polarised beams. A multichannel PMT is used to detect scintillation light. The rate of detectable scintillation events is about three orders of magnitude lower compared to the rate of ionisation events. To boost the photon yield, small amounts of nitrogen are injected into the SPM vacuum chamber. An adjustable light focusing system is being built to optimise the SPM performance for different machine operation modes. The new system allows using a variety of optical components ranging from single lenses to high-grade camera objectives. Cylindrical lenses are considered to further boost the sensitivity by better fitting the beam image to the detector geometry. The latest experimental results and the new design of the optical system are presented. | ||
MOPB78 |
Beam Spot Measurement using a Phosphor Screen for Carbon-Ion Therapy at NIRS | |
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| A two-dimensional beam imaging system with a terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) phosphor screen and high-speed charge coupled device (CCD) camera has been used to measure the beam spot for scanned carbon-ion therapy at National Institute of Radiological Sciences (NIRS). The system enables us to obtain one image of the beam spot every 20 milliseconds. The fluctuation of the unscanned-beam spot size and position was observed in the isocenter to verify the time stability of the delivered beam for scanning irradiation. The beam imaging system also functions as a beam alignment adjustment system by setting a steel sphere at the isocenter. For quality assurance, the beam alignment is routinely checked by observing a shadow of the steel sphere on the beam spot image, and it is confirmed that the misalignment of the beam is smaller than the tolerance of 0.5 mm. | ||
MOPB79 |
Design of a High-precision Fast Wire Scanner for the SPS at CERN | |
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| Studies are going on of a new wire scanner concept. All moving parts are inside the beam vacuum and it is specified for use in all the machines across the CERN accelerator complex. Key components have been developed and tested. Work is now focussing on the installation of a prototype for test in the Super Proton Synchrotron (SPS) accelerator. This article presents the specification of the device and constraints on the design for integration in the different accelerators at CERN. The design issues of the mechanical components are discussed and optimisation work shown. Finally, the prototype design, integrating the several components into the vacuum tank is presented. | ||
MOPB80 |
High Dynamic Range Beam Imaging with Two Simultaneously Sampling CCDs | |
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| Transverse beam profile measurement with sufficiently high dynamic range (HDR) is a key diagnostic to measure the beam halo, understand its sources and evolution. In this contribution we describe our initial experience with the HDR imaging of the electron beam at the JLab FEL. On contrary to HDR measurements made with wire scanners in counting mode, which provide only two or three 1D projections of transverse beam distribution, imaging allows to measure the distribution itself. That is especially important for non-equilibrium beams in the LINACs. The measurements were made by means of simultaneous imaging with two CCD sensors with different exposure time. Two images are combined then numerically in to one HDR image. The system works as an online tool providing HDR images at 4 Hz. An optically polished YAG:Ce crystal with the thickness of 100 um was used for the measurements. When tested with a laser beam images with the DR of about 10+5 were obtained. With the electron beam the DR was somewhat smaller due to the limitations in the time structure of the tune-up beam macro pulse. | ||
MOPB81 |
Residual Gas Ionization Profile Monitors in J-PARC Slow-extraction Beam Line | |
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| Residual gas ionization profile monitors (RGIPMs) working in 1 Pa pressure have been developed for high-intensity proton beam (maximum: 50GeV-15uA) at J-PARC slow-extraction beam line. The transverse beam profiles are measured by collecting electrons produced by ionization of 1 Pa residual gas. The electrons are guided to the segmented electrode with a uniform electrostatic field applied in the gap. A uniform magnetic field is applied parallel to the electric field to reduce diffusion of electrons travelling to the electrodes. Typical spatial resolution of the RGIPMs with a 10 cm gap, a 10 V/cm electrostatic field, and a 400 gauss magnetic field at center is 0.5 mm. The collected charge is integrated during every extraction period (typically 2 second in 6 second accelerator cycle). Subtracting background distributions measured during off-beam period, profile distributions are measured clearly. The 14 RGIPMs installed in the slow-extraction beam line are working stably for the 30 GeV-0.46 uA proton beam at current maximum. In this contribution, detailed specifications and performance of the present RGIPMs will be reported. | ||
MOPB82 |
Bunch-Compressor Transverse Profile Monitors of the SwissFEL Injector Test Facility | |
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| The 250 MeV SwissFEL Injector Test Facility (SITF) is the test bed of the future 5.7 GeV SwissFEL linac that will drive a coherent FEL light source in the wavelength range 7-0.7 and 0.7-0.1 nm. Aim of the SITF is to demonstrate the technical feasibility of producing and measuring 10 or 200pC electron bunches with normalized emittance down to 0.25 μm. A further goal is to demonstrate that the electron beam quality is preserved in the acceleration process, in the X-Band linearizer and the magnetic compression from about 10 ps down to 200 fs. The SITF movable magnetic bunch-compressor is equipped with several CCD/CMOS cameras for monitoring the beam transverse profile and determining the beam energy spread: a Ce:YAG screen and an OTR screen camera at the mid-point of the bunch compressor and a SR camera imaging in the visible the Synchrotron Radiation emitted by the electron beam crossing the third dipole. Results on the commissioning of such instrumentations, in particular in the low charge limit, and measurements of the beam energy spread vs. the compression factor will be presented. | ||
MOPB83 |
Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring | |
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| A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process. | ||
MOPB85 |
Latest Results from the 4.8GHz LHC Schottky System | |
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| This paper will present the latest results from the LHC 4.8GHz travelling wave Schottky system, summarising measurements performed during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies. | ||
MOPB86 |
Betatron Tune Measurement and Automatic Correction Systems at NewSUBARU Storage Ring | |
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| At the 1.5GeV electron storage ring NewSUBARU, the two different kinds of systems for measuring betatron tunes have been developed: the high precision tune monitor and that for automatic correction. The vertical and horizontal tunes can be observed during the user time, because a stripe-line kicker to enlarge the beam lifetime vertically shakes electron beams. The high-precision tune monitor has the resolution of 0.0002 and uses frequency analysis methods such as SRSA, zoom FFT, STFT, in addition to usual FFT. Tune shifts due to a slight difference of filling patterns during top-up operations can be observed with this monitor. The another tune monitoring and automatic-correcting system has been developed to compensate tune shifts caused by the decrease of the stored current, the difference of filling patterns during top-up operations, and the energy ramp from 1.0 to 1.5 GeV. This system estimates betatron tunes every 0.5 sec and can keep tunes to the optimal values. The system also has a tune survey function that can automatically measure the beam lifetime in a tune diagram. | ||
MOPB87 |
Development and First Tests of a High Sensitivity Charge Monitor for SwissFEL | |
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| The compact X-ray free electron laser SwissFEL, which is presently under development at the Paul Scherrer Institut (PSI) in Villigen, Switzerland, will operate at comparably low charges, allowing the compression of the electron bunches to a few femto-seconds (nominal 200 pC mode) and even towards the atto-second range (short bunch 10 pC mode). A high precision charge measurement turns out to be a challenge, especially in the presence of dark currents, which may occur from high gradient RF gun and accelerating structure operation. In response to this challenge, a higher sensitivity charge transformer and new beam charge monitor electronics were developed in collaboration between Bergoz Instrumentation and PSI. The Turbo-ICT captures sub-pC bunch charge thanks to a new magnetic alloy exhibiting very low core loss. Transmission over a carrier using narrow-band cable television technique preserves the signal integrity from the Turbo-ICT to the BCM-RF. Electro-magnetic and RF interferences are strongly attenuated; the dark current signal is suppressed. First beam test results, which have been performed at the SwissFEL Test Injector Facility (STIF), are presented in this contribution. | ||