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Sample records for beam loss monitor

  1. Application of Diamond Based Beam Loss Monitors

    OpenAIRE

    Hempel, Maria

    2013-01-01

    The LHC has an operational stored energy of 130MJ per beam. Only a small percentage of beam losses in the LHC equipment can damage material or lead to magnet quenches. Therefore, it is important to monitor different types of beam losses, e.g. scattering on residual gas particles, UFOs, collisions and injection losses. A detailed understanding of beam loss mechanisms is necessary to reduce them and ensure save operation. Two different beam loss monitors are installed in the LHC tunnel: ionizat...

  2. Application of diamond based beam loss monitors

    International Nuclear Information System (INIS)

    The LHC has an operational stored energy of 130MJ per beam. Only a small percentage of beam losses in the LHC equipment can damage material or lead to magnet quenches. Therefore, it is important to monitor different types of beam losses, e.g. scattering on residual gas particles, UFOs, collisions and injection losses. A detailed understanding of beam loss mechanisms is necessary to reduce them and ensure save operation. Two different beam loss monitors are installed in the LHC tunnel: ionization chambers and diamond sensors. Ionization chambers trigger a beam dump if beam losses exceed a certain threshold. They have a time resolution of 40um (half LHC turn) which is not sufficient to resolve bunch-by-bunch beam losses. Diamond sensors have a nanosecond time resolution and can therefore detect bunch-by-bunch beam losses. This time resolution allows an analysis of various types of beam losses and an understanding of the mechanisms. For the first time beam loss intensities were measured bunch-by-bunch caused by different origins of losses. Beam loss measurements using diamond sensors will be presented. The results are compared to simulations and good qualitative agreement was found. The potential of diamond sensors for LHC and experiment applications are discussed.

  3. Application of diamond based beam loss monitors

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, Maria [Brandenburgische Technische Univ. Cottbus (Germany); DESY, Zeuthen (Germany); CERN, Geneva (Switzerland); Baer, Tobias [CERN, Geneva (Switzerland); Hamburg Univ. (Germany); Castro Carballo, Elena Maria [DESY, Zeuthen (Germany); Lohmann, Wolfgang [Brandenburgische Technische Univ. Cottbus (Germany); DESY, Zeuthen (Germany); Schmidt, Ruediger [CERN, Geneva (Switzerland)

    2013-07-01

    The LHC has an operational stored energy of 130MJ per beam. Only a small percentage of beam losses in the LHC equipment can damage material or lead to magnet quenches. Therefore, it is important to monitor different types of beam losses, e.g. scattering on residual gas particles, UFOs, collisions and injection losses. A detailed understanding of beam loss mechanisms is necessary to reduce them and ensure save operation. Two different beam loss monitors are installed in the LHC tunnel: ionization chambers and diamond sensors. Ionization chambers trigger a beam dump if beam losses exceed a certain threshold. They have a time resolution of 40um (half LHC turn) which is not sufficient to resolve bunch-by-bunch beam losses. Diamond sensors have a nanosecond time resolution and can therefore detect bunch-by-bunch beam losses. This time resolution allows an analysis of various types of beam losses and an understanding of the mechanisms. For the first time beam loss intensities were measured bunch-by-bunch caused by different origins of losses. Beam loss measurements using diamond sensors will be presented. The results are compared to simulations and good qualitative agreement was found. The potential of diamond sensors for LHC and experiment applications are discussed.

  4. Requirements of CLIC Beam Loss Monitoring System

    CERN Document Server

    Sapinski, M; Holzer, EB; Jonker, M; Mallows, S; Otto, T; Welsch, C

    2010-01-01

    The Compact Linear Collider (CLIC) [1] is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel twobeam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine, because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring (BLM) system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. The two-beam module where the protection from beam losses is particularly challenging and important, is studied.

  5. Beam Loss Monitors at the ESRF

    CERN Document Server

    Joly, B; Naylor, G A

    2000-01-01

    The European Synchrotron radiation facility is a third generation x-ray source providing x-rays on a continuous basis. As a facility available to external users, the monitoring of radiation caused by the loss of high-energy stored beam is of great concern. A network of beam loss monitors has been installed inside the storage ring tunnel so as to detect and localize the slow loss of electrons during a beam decay. This diagnostic tool allows optimization of beam parameters and physical aperture limits as well as giving useful information on the machine to allow the lifetime to be optimized and defects localized.

  6. Beam Loss Monitors at LHC

    CERN Document Server

    Dehning, B

    2016-01-01

    One of the main functions of the LHC beam loss measurement system is the protection of equipment against damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Reliability requirements are scaled according to the acceptable consequences and the frequency of particle impact events on equipment. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability; therefore, an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions for the LHC system will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations to the requirements for operation and documentation.

  7. Application of optical fiber beam loss monitor

    International Nuclear Information System (INIS)

    KEK is an accelerator complex consisting of an electron-positron injector linac and various types of circular accelerators. In order to protect instruments from radiation damage, discrete beam loss monitors have been installed inside the linac and rings. Although beam losses can be detected using the beam loss monitors (BLMs) or beam position monitors (BPMs), it is difficult to identify the exact position of the loss. The electrons, which strike the duct, lose a fraction of their beam energy, which produces a shower at the location and emits many electrons out of the duct. If an optical fiber is placed inside the beam duct, many of these electrons will pass through the optical fiber where the beam loss is generated. BLMs employing an optical fiber based on Cherenkov radiation are currently being developed and applied to our system. An optical fiber placed into the duct also can be used as a detector for a wire scanner system. Existing wire scanner detectors are set at a fixed position, and detect signals of different beam energies that correspond to the different injection modes. However, the fixed position is not always optimal. Conversely, owing to the optical fiber's distributing nature, optical fiber detector systems containing PMTs enables the effective detection of all signals from various beam modes. We can successfully obtain the clear wire scanner signal by employing this optical fiber system. The measurement of the beam loss at the incidence part of the circular accelerator is also described. The beam loss location as well as the turn-by-turn beam loss can be measured. (author)

  8. Cryogenic Beam Loss Monitoring for the LHC

    CERN Document Server

    Kurfuerst, C; Sapinski, M

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. T...

  9. Fast-response beam loss monitor

    International Nuclear Information System (INIS)

    By connecting a polyethylene fiber to a photo-multiplier, a beam loss monitor with a fast response has been fabricated. The beam loss is measured by Cherenkov light generated by a charged particle penetrating a fiber. Although this monitor has the merits that the structure of the monitor is simple and cheap, it has the demerits that the signal has an energy dependence, and deterioration caused by radiation occurs. A plastic scintillating fiber and a quartz fiber have also been tested. The signal of the former fiber is strong and does not depend on the energy of the circulating beam. However, the deterioration is also very severe. On the contrary, the latter fiber has a long lifetime, though its signal is small. Some measurements are discussed here concerning various cases of extraction conditions. (author)

  10. RHIC beam loss monitor system design

    International Nuclear Information System (INIS)

    The Beam Loss Monitor (BLM) System is designed to prevent the quenching of RHIC magnets due to beam loss, provide quantitative loss data, and the loss history in the event of a beam abort. The system uses 400 ion chambers of a modified Tevatron design. To satisfy fast (single turn) and slow (100 msec) loss beam criteria and provide sensitivity for studies measurements, a range of over 8 decades is needed. An RC pre-integrator reduces the dynamic range for a low current amplifier. This is digitized for data logging. The output is also applied to an analog multiplier which compensates the energy dependence, extending the range of the abort comparators. High and low pass filters separate the signal to dual comparators with independent programmable trip levels. Up to 64 channels, on 8 VME boards, are controlled by a micro-controller based VME module, decoupling it from the front-end computer (FEC) for real-time operation. Results with the detectors in the RHIC Sextant Test and the electronics in the AGS-to-RHIC (AtR) transfer line will be presented

  11. Beam loss monitor system for the SSC

    International Nuclear Information System (INIS)

    At full intensity the energy contained in each beam of the Superconducting Super Collider (SSC) is 400 MJ. The loss of a small fraction of that beam has the potential to cause magnet quenches or even severe damage to Collider components. To help protect the machine a sensitive and reliable beam loss monitor (BLM) system must be designed and built. In fact, BLM systems will be needed for all the accelerators of the SSC. The BLM system requirements for each of these accelerators will be discussed, but emphasis will be placed on the Collider. The discussion will include the preliminary design of BLM systems, the considerations that led to these designs, the calculations that were performed in development of the designs, and the problems that remain to be solved. A major tool in the design process has been a series of Monte Carlo calculations that were used to estimate beam loss distributions for the Collider arcs, the interaction regions, and the west utility region. These calculations were also used to study the fluence as a function of energy, the particle content, and the dose rate at selected positions. Detailed considerations such as detector spacing and sensitivity, loss fluctuations, reliability, and maintainability will be discussed. The proposed preliminary BLM system design for the Collider uses a radiation-hard, solid-state ionization detector and fast analog-to-digital conversion. Details of this design and relevant options will be discussed

  12. The AGS Booster beam loss monitor system

    International Nuclear Information System (INIS)

    A beam loss monitor system has been developed for the Brookhaven National Laboratory Booster accelerator, and is designed for use with intensities of up to 1.5 x 1013 protons and carbon to gold ions at 50-3 x 109 ions per pulse. This system is a significant advance over the present AGS system by improving the sensitivity, dynamic range, and data acquisition. In addition to the large dynamic range achievable, it is adaptively shifted when high losses are detected. The system uses up to 80 argon filled ion chambers as detectors, as well as newly designed electronics for processing and digitizing detector outputs. The hardware simultaneously integrates each detector output, interfaces to the beam interrupt systems, and digitizes all 80 channels to 21 bits at 170 KHz. This paper discuses the design, construction, and operation of the system. 4 refs., 2 figs

  13. Cryogenic beam loss monitoring for the LHC

    International Nuclear Information System (INIS)

    A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. The advantage is that the dose measured by the Cryogenic Beam Loss Monitor (CryoBLM) would more precisely correspond to the dose deposited in the superconducting coil. The main challenges of this placement are the low temperature of 1.9 K and the integrated dose of 2 MGy in 20 years. Furthermore the CryoBLM should work in a magnetic field of 2 T and at a pressure of 1.1 bar, withstanding a fast pressure rise up to 20 bar in case of a magnet quench. The detector response should be linear between 0.1 and 10 mGy/s and faster than 1 ms. Once the detectors are installed in the LHC magnets, no access will be possible. Hence the detectors need to be available, reliable and stable for 20 years. Following intense research it became clear that no existing technology was proven to work in such conditions. The candidates under investigation in this work are diamond and silicon detectors and an ionisation chamber, using the liquid helium itself as particle detection medium

  14. First Experience with the LHC Beam Loss Monitoring System

    CERN Document Server

    Böhlen, T; Effinger, E; Emery, J; Follin, F; Holzer, E; Jackson, S; Kramer, Daniel; Kruk, G; Le Roux, P; Mariethoz, J; Misiowiec, M; Ponce, L; Roderick, C; Sapinski, M; Zamantzas, C; Stockner, M; Bocian, D; Grishin, V; Ikeda, H; Priebe, A

    2010-01-01

    The LHC beam loss monitoring system (BLM) consists of about 4000 monitors observing losses at all quadrupole magnets and many other likely loss locations. At the first LHC operation in August and September 2008 all monitors were active and used to observe the losses during the initial beam steerings, at collimators, at the LHC dump and during aperture scans. The different acquisition modes and their presentation are shown. Aperture scan loss patterns and a detailed loss pattern leading to a magnet quench are discussed. The observed signals of the BLM system are analyzed in terms of response time, sensitivity and noise performance.

  15. The N8 channel beam loss monitor system

    International Nuclear Information System (INIS)

    High intensity 70 GeV proton beam loss monitor system architecture in the area of single beam pass is described. The main system components choosing as detectors recording and controlling electronics are grounded on. There are list of the main system monitoring tasks and some experimental results. 12 refs.; 6 figs

  16. LHC Beam Loss Monitoring System Verification Applications

    CERN Document Server

    Dehning, B; Zamantzas, C; Jackson, S

    2011-01-01

    The LHC Beam Loss Mon­i­tor­ing (BLM) sys­tem is one of the most com­plex in­stru­men­ta­tion sys­tems de­ployed in the LHC. In ad­di­tion to protecting the col­lid­er, the sys­tem also needs to pro­vide a means of di­ag­nos­ing ma­chine faults and de­liv­er a feed­back of loss­es to the control room as well as to sev­er­al sys­tems for their setup and analysis. It has to trans­mit and pro­cess sig­nals from al­most 4’000 mon­i­tors, and has near­ly 3 mil­lion con­fig­urable pa­ram­e­ters. The system was de­signed with re­li­a­bil­i­ty and avail­abil­i­ty in mind. The spec­i­fied op­er­a­tion and the fail-safe­ty stan­dards must be guar­an­teed for the sys­tem to per­form its func­tion in pre­vent­ing su­per­con­duc­tive mag­net de­struc­tion caused by par­ti­cle flux. Main­tain­ing the ex­pect­ed re­li­a­bil­i­ty re­quires ex­ten­sive test­ing and ver­i­fi­ca­tion. In this paper we re­port our most re­cent ad­di­t...

  17. A Versatile Beam Loss Monitoring System for CLIC

    CERN Document Server

    Kastriotou, Maria; Farabolini, Wilfrid; Holzer, Eva Barbara; Nebot Del Busto, Eduardo; Tecker, Frank; Welsch, Carsten

    2016-01-01

    The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to qu...

  18. Performance and perspectives of the diamond based Beam Condition Monitor for beam loss monitoring at CMS

    CERN Document Server

    AUTHOR|(CDS)2080862

    2015-01-01

    At CMS, a beam loss monitoring system is operated to protect the silicon detectors from high particle rates, arising from intense beam loss events. As detectors, poly-crystalline CVD diamond sensors are placed around the beam pipe at several locations inside CMS. In case of extremely high detector currents, the LHC beams are automatically extracted from the LHC rings.Diamond is the detector material of choice due to its radiation hardness. Predictions of the detector lifetime were made based on FLUKA monte-carlo simulations and irradiation test results from the RD42 collaboration, which attested no significant radiation damage over several years.During the LHC operational Run1 (2010 â?? 2013), the detector efficiencies were monitored. A signal decrease of about 50 times stronger than expectations was observed in the in-situ radiation environment. Electric field deformations due to charge carriers, trapped in radiation induced lattice defects, are responsible for this signal decrease. This so-called polarizat...

  19. Development of fiber beam loss monitor based on Cerenkov principle

    International Nuclear Information System (INIS)

    Background: A new type of beam loss monitor (BLM) system is needed in the synchrotron radiation light source or FEL facility to monitor the real-time beam loss inside the small-gap insertion devices. Purpose: A BLM system was developed with optical fiber as the probe to meet the requirements of SSRF. Methods: The whole system consists of a 30-m long step-index fiber, photomultiplier tubes (PMT), a 10-bit 8-GS/s high-speed waveform digitizer and a PXI input-output controller. The software was developed under the Linux system based on Experimental Physics and Industrial Control System (EPICS). A new measurement and corresponding calculation method were designed to make the system work well with the multi-bunch operation mode in the storage ring of SSRF. Results: The BLM system worked well at SSRF. And the results of beam experiments showed that the system could detect beam loss properly even at the 1-mA low current case. Conclusions: This system could be used in the detection of beam loss dose and position. In the experiments the counts of light pulses can be used as a rough estimation of beam loss dose. The noise floor is about 3.56% of the total count in the 220-mA top-up user operation mode. (authors)

  20. IFMIF-LIPAc Beam Diagnostics. Profiling and Loss Monitoring Systems

    International Nuclear Information System (INIS)

    The IFMIF accelerator will accelerate two 125 mA continuous wave (cw) deuteron beams up to 40 MeV and blasts them onto a liquid lithium target to release neutrons. The very high beam power of 10 MW pose unprecedented challenges for the accelerator development. Therefore, it was decided to build a prototype accelerator, the Linear IFMIF Prototype Accelerator (LIPAc), which has the very same beam characteristic, but is limited to 9 MeV only. In the frame of this thesis, diagnostics devices for IFMIF and LIPAc have been developed. The diagnostics devices consist of beam loss monitors and interceptive as well as non-interceptive profile monitors. For the beam loss monitoring system, ionization chambers and diamond detectors have been tested and calibrated for neutron and γ radiation in the energy range expected at LIPAc. During these tests, for the first time, diamond detectors were successfully operated at cryogenic temperatures. For the interceptive profilers, thermal simulations were performed to ensure safe operation. For the non-interceptive profiler, Ionization Profile Monitors (IPMs) were developed. A prototype has been built and tested, and based on the findings, the final IPMs were designed and built. To overcome the space charge of accelerator beam, a software algorithm was written to reconstruct the actual beam profile. (author)

  1. Application of diamond based beam loss monitors at LHC

    International Nuclear Information System (INIS)

    The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in the LHC, especially near each quadrupole and next to

  2. Application of diamond based beam loss monitors at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, Maria

    2013-04-15

    The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in

  3. Beam Loss Position Monitor Using Cerenkov Radiation in Optical Fibers

    CERN Document Server

    Körfer, M

    2005-01-01

    Single pass Free Electron Lasers SASE-FELs are developed for high brightness and short wavelength applications. The VUV-FEL at DESY will reach an average beam power of about 72 kW. To avoid particle losses in the radiation sensitive undulators a collimator system is installed. However, the proper operation of the collimator system needs to be measured with a beam loss monitor. Conventional radiation sensor systems are not suited for the VUV-FEL undulators, because the free space in the undulator gap is less than 1 mm. A Beam Loss Position Monitor (BLPM) based on Cerenkov light in optical fibers allows the monitoring of losses inside the undulator. Electrons with energies above 175 keV generate Cerenkov light during their penetration of the optical fiber. The fast response of the Cerenkov signal is detected with photomultipliers at the end of the irradiated fibers. The beam loss position along the section of interest can be determinate by exploiting the system trigger (bunch clock) of the accelerator system. T...

  4. Configuration and Validation of the LHC Beam Loss Monitoring System

    CERN Document Server

    Zamantzas, C; Emery, J; Fitzek, J; Follin, F; Jackson, S; Kain, V; Kruk, G; Misiowiec, M; Roderick, C; Sapinski, M

    2009-01-01

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. As well as protecting the machine, the system is also used as a means of diagnosing machine faults, and providing feedback of losses to the control room and several systems such as the Collimation, the Beam Dump and the Post-Mortem. The system has to transmit and process signals from over 4’000 monitors, and has approaching 3 million configurable parameters. This paper describes the types of configuration data needed, the means used to store and deploy all the parameters in such a distributed system and how operators are able to alter the operating parameters of the system, particularly with regard to the loss threshold values. The various security mechanisms put in place, both at the hardware and software level, to avoid accidental or malicious modification of these BLM parameters are also shown for each case.

  5. Accelerator Physics Experiments with Beam Loss Monitors at BESSY

    CERN Document Server

    Kuske, P

    2001-01-01

    The extended use of beam loss monitoring has led to a better understanding of the linear and non-linear physics involved in the single and multiple particle dynamics at BESSY. This knowledge has been used for improving the performance of the light source in terms of lifetime, beam stability, and stability of the energy. The key to these experiments are loss monitors placed at strategic locations of the ring with high sensitivity to Touschek or Coulomb scattered particles. Coulomb-scattering depends strongly on the transverse dynamics which is determined by the magnetic guiding fields. Losses occur primarily at the vertical aperture restrictions imposed by the flat insertion device vacuum chambers. Tune scan measurements clearly show resonances produced by the lattice magnets and by some of the insertion devices. Touschek scattering depends on the 3-dimensional electron density and the spins of the colliding particles. In transfer function type experiments these dependencies have been used to observe the effec...

  6. Radiation Tolerance of Cryogenic Beam Loss Monitor Detectors

    CERN Document Server

    Kurfuerst, C; Bartosik, M; Dehning, B; Eisel, T; Sapinski, M; Eremin, V; Verbitskaya, E; Fabjan, C; Griesmayer, E

    2013-01-01

    At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring system is sensitive to the particle showers resulting from the collision of the two beams. For the future, with beams of higher energy and intensity resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. Investigations are therefore underway to optimise the system by locating the beam loss detectors as close as possible to the superconducting coils of the triplet magnets. This means putting detectors inside the cold mass in superfluid helium at 1.9 K. Previous tests have shown that solid state diamond and silicon detectors as well as liquid helium ionisation chambers are promising candidates. This paper will address the final open question of their radiation resistance for 20 years of nominal LHC operation, by reporting on the results from high irradiation beam tests carried out at CERN in a...

  7. Beam Loss Monitoring for Run 2 of the LHC

    CERN Document Server

    Kalliokoski, Matti; Dehning, Bernd; Domingues Sousa, Fernando; Effinger, Ewald; Emery, Jonathan; Grishin, Viatcheslav; Holzer, Eva Barbara; Jackson, Stephen; Kolad, Blazej; Nebot Del Busto, Eduardo; Picha, Ondrej; Roderick, Chris; Sapinski, Mariusz; Sobieszek, Marcin; Zamantzas, Christos

    2015-01-01

    The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss...

  8. Test of the LHC DIAMOND Beam Loss Monitors

    CERN Document Server

    Dehning, B; Effinger, E; Pernegger, H; Griesmayer, E

    2011-01-01

    Chemical Vapour Deposition(CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-­radiation environment. Four detectors were configured with fast, radiation-­hard pre-amplifiers with a bandwidth of 2GHz. The readout was via an oscilloscope with a bandwidth of 1GHz and a sampling rate of 5 GSPS. Despite the 250m cable run from the detectors to the oscilloscope, particle losses were resolved with a 2ns rise time, a pulse width of 10ns and a time resolution of 615ps. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2us. Measurements during the LHC start-­up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the LHC RF freq...

  9. A Fast CVD Diamond Beam Loss Monitor for LHC

    CERN Document Server

    Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

    2011-01-01

    Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

  10. Application of Diamond Based Beam Loss Monitors at LHC

    CERN Document Server

    Hempel, Maria; Rüdiger, S.

    2013-05-14

    The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus (ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due...

  11. The LCLS Undulator Beam Loss Monitor Readout System

    Energy Technology Data Exchange (ETDEWEB)

    Dusatko, John; Browne, M.; Fisher, A.S.; Kotturi, D.; Norum, S.; Olsen, J.; /SLAC

    2012-07-23

    The LCLS Undulator Beam Loss Monitor System is required to detect any loss radiation seen by the FEL undulators. The undulator segments consist of permanent magnets which are very sensitive to radiation damage. The operational goal is to keep demagnetization below 0.01% over the life of the LCLS. The BLM system is designed to help achieve this goal by detecting any loss radiation and indicating a fault condition if the radiation level exceeds a certain threshold. Upon reception of this fault signal, the LCLS Machine Protection System takes appropriate action by either halting or rate limiting the beam. The BLM detector consists of a PMT coupled to a Cherenkov radiator located near the upstream end of each undulator segment. There are 33 BLMs in the system, one per segment. The detectors are read out by a dedicated system that is integrated directly into the LCLS MPS. The BLM readout system provides monitoring of radiation levels, computation of integrated doses, detection of radiation excursions beyond set thresholds, fault reporting and control of BLM system functions. This paper describes the design, construction and operational performance of the BLM readout system.

  12. Development, Production and Testing of 4500 Beam Loss Monitors

    CERN Document Server

    Holzer, E B; Dehning, B; Ferioli, G; Grishin, V; Jimenez, T M; Koshelev, A; Kramer, Daniel; Larionov, A; Taborelli, M; Seleznev, V; Sleptsov, M; Sytin, A; Wevers, I

    2008-01-01

    Beam-loss monitoring (BLM) [1] is a key element in the LHC machine protection. 4250 nitrogen filled ionization chambers (IC) and 350 secondary emission monitors (SEM) have been manufactured and tested at the Institute for High Energy Physics (IHEP) in Protvino, Russia, following their development at CERN. Signal speed and robustness against aging were the main design criteria. Each monitor is permanently sealed inside a stainless-steel cylinder. The quality of the welding was a critical aspect during production. The SEMs are requested to hold a vacuum of $10^{-7}$ bar. Impurity levels from thermal and radiationinduced desorption should remain in the range of parts per million in the ICs. To avoid radiation aging (up to $2·10^{8}$ Gy in 20 years) production of the chambers followed strict UHV requirements. IHEP designed and built the UHV production stand. Due to the required dynamic range of $10^{8}$, the leakage current of the monitors has to stay below 2 pA. Several tests during and after production were ...

  13. Reliability Tests of the LHC Beam Loss Monitoring FPGA Firmware

    CERN Document Server

    Hajdu, C F; Dehning, B; Jackson, S

    2010-01-01

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver a feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from almost 4’000 monitors, and has nearly 3 million configurable parameters. In a system of such complexity, firmware reliability is a critical issue. The integrity of the signal chain of the LHC BLM system and its ability to correctly detect unwanted scenarios and thus provide the required protection level must be ensured. In order to analyze the reliability and functionality, an advanced verification environment has been developed to evaluate the performance and response of the FPGA-based data analysis firmware. This paper will report on the numerous tests that have been performed and on how the results are used to quantify the reliabi...

  14. Cherenkov Fibers for Beam Loss Monitoring at the CLIC Two Beam Module

    CERN Document Server

    van Hoorne, Jacobus Willem; Holzer, E B

    The Compact Linear Collider (CLIC) study is a feasibility study aiming at a nominal center of mass energy of 3TeV and is based on normal conducting travelling-wave accelerating structures, operating at very high field gradients of 100 MV/m. Such high fields require high peak power and hence a novel power source, the CLIC two beam system, has been developed, in which a high intensity, low energy drive beam (DB) supplies energy to a high energy, low intensity main beam (MB). At the Two Beam Modules (TBM), which compose the 2x21km long CLIC main linac, a protection against beam losses resulting from badly controlled beams is necessary and particularly challenging, since the beam power of both main beam (14 MW) and drive beam (70 MW) is impressive. To avoid operational downtimes and severe damages to machine components, a general Machine Protection System (MPS) scheme has been developed. The Beam Loss Monitoring (BLM) system is a key element of the CLIC machine protection system. Its main role will be to detect p...

  15. Cryogenic Beam Loss Monitors for the Superconducting Magnets of the LHC

    CERN Document Server

    Bartosik, MR; Sapinski, M; Kurfuerst, C; Griesmayer, E; Eremin, V; Verbitskaya, E

    2014-01-01

    The Beam Loss Monitor detectors close to the interaction points of the Large Hadron Collider are currently located outside the cryostat, far from the superconducting coils of the magnets. In addition to their sensitivity to lost beam particles, they also detect particles coming from the experimental collisions, which do not contribute significantly to the heat deposition in the superconducting coils. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and dangerous quench-provoking beam losses from the primary proton beams will be challenging. The system can be optimised by locating beam loss monitors as close as possible to the superconducting coils, inside the cold mass in a superfluid helium environment, at 1.9 K. The dose then measured by such Cryogenic Beam Loss Monitors would more precisely correspond to the real dose deposited in the coil. The candidates under investigation for such detectors are based on p+-n-n+ si...

  16. The upgraded data acquisition system for beam loss monitoring at the Fermilab Tevatron and Main Injector

    OpenAIRE

    Baumbaugh, A.; Briegel, C.; Brown, B. C.; Capista, D.; Drennan, C.; Fellenz, B.; Knickerbocker, K.; Lewis, J.D.; Marchionni, A.; Needles, C.; Olson, M.; S. Pordes; Shi, Z; Still, D.; Thurman-Keup, R.

    2011-01-01

    A VME-based data acquisition system for beam-loss monitors has been developed and is in use in the Tevatron and Main Injector accelerators at the Fermilab complex. The need for enhanced beam-loss protection when the Tevatron is operating in collider-mode was the main driving force for the new design. Prior to the implementation of the present system, the beam-loss monitor system was disabled during collider operation and protection of the Tevatron magnets relied on the quench protection syste...

  17. Reliability of Beam Loss Monitor Systems for the Large Hadron Collider

    CERN Document Server

    Guaglio, Gianluca; Santoni, C

    2005-01-01

    The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data...

  18. The upgraded data acquisition system for beam loss monitoring at the Fermilab Tevatron and Main Injector

    CERN Document Server

    Baumbaugh, A; Brown, B C; Capista, D; Drennan, C; Fellenz, B; Knickerbocker, K; Lewis, J D; Marchionni, A; Needles, C; Olson, M; Pordes, S; Shi, Z; Still, D; Thurman-Keup, R; Utes, M; Wu, J

    2011-01-01

    A VME-based data acquisition system for beam-loss monitors has been developed and is in use in the Tevatron and Main Injector accelerators at the Fermilab complex. The need for enhanced beam-loss protection when the Tevatron is operating in collider-mode was the main driving force for the new design. Prior to the implementation of the present system, the beam-loss monitor system was disabled during collider operation and protection of the Tevatron magnets relied on the quench protection system. The new Beam-Loss Monitor system allows appropriate abort logic and thresholds to be set over the full set of collider operating conditions. The system also records a history of beam-loss data prior to a beam-abort event for post-abort analysis. Installation of the Main Injector system occurred in the fall of 2006 and the Tevatron system in the summer of 2007. Both systems were fully operation by the summer of 2008. In this paper we report on the overall system design, provide a description of its normal operation, and...

  19. Distributed beam loss monitor based on the Cherenkov effect in an optical fiber

    Science.gov (United States)

    Maltseva, Yu; Emanov, F. A.; Petrenko, A. V.; Prisekin, V. G.

    2015-05-01

    This review discusses a distributed beam loss monitor which is based on the Cherenkov effect in an optical fiber and which has been installed at the VEPP-5 Injection Complex at the Budker Institute of Nuclear Physics. The principle of the device operation consists in detecting the Cherenkov radiation generated in an optical fiber by relativistic charged particles that are produced in an electromagnetic shower when highly relativistic beam particles (electrons or positrons) hit the accelerator vacuum chamber wall. Our experiments used a photomultiplier tube (PMT) to detect the Cherenkov light. Knowing when the PMT signal arrives tells us where the beam loss occurs. Using a 20-m-long optical fiber allowed a detector spatial resolution of 3 m. The way to improve the resolution is to optimize the monitor working conditions and optical fiber and PMT parameters, potentially leading to a resolution of as fine as 0.5 m according to our estimates.

  20. Beam loss monitor system of the rapid cycling synchrotron of Japan Proton Accelerator Research Complex

    International Nuclear Information System (INIS)

    The 3 GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) provides more than 300 kW beam to the Material and Life Science Facility (MLF) and the Main Ring (MR). In such high intensity hadron accelerator, the lost protons that are a fraction of the beam less than 0.1% cause many problems. Those particles bring about a serious radioactivation and a malfunction of the accelerator components. Therefore, the beam loss monitor (BLM) is one of the most important equipment to observe the state of the beam during operation, and to keep a steady operation. Moreover, if we set operation parameters of BLM adequately, it can detect the beam loss that is 10-6 fraction of the beam. Thus it enables fine-tuning of the accelerator. In the J-PARC RCS, a proportional counter and a plastic scintillation counter are used for the beam commission and the stable operation as BLM. We report present status of the BLM system in J-PARC RCS. (author)

  1. Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN

    CERN Document Server

    Guaglio, G; Santoni, C

    2005-01-01

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out....

  2. A Compactrio-Based Beam Loss Monitor For The SNS RF Test Cave

    International Nuclear Information System (INIS)

    An RF Test Cave has been built at the Spallation Neutron Source (SNS) to be able to test RF cavities without interfering the SNS accelerator operations. In addition to using thick concrete wall to minimize radiation exposure, a Beam Loss Monitor (BLM) must abort the operation within 100 usec when the integrated radiation within the cave exceeds a threshold. We choose the CompactRIO platform to implement the BLM based on its performance, cost-effectiveness, and rapid development. Each in/output module is connected through an FPGA to provide point-by-point processing. Every 10 usec the data is acquired analyzed and compared to the threshold. Data from the FPGA is transferred using DMA to the real-time controller, which communicates to a gateway PC to talk to the SNS control system. The system includes diagnostics to test the hardware and integrates the losses in real-time. In this paper we describe our design, implementation, and results

  3. Reliability of the beam loss monitors system for the large hadron collider at CERN

    International Nuclear Information System (INIS)

    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out. The reliability figures of the BLMS have been calculated using a commercial software package (Isograph.). The effect of the variation of the parameters on the obtained results has been evaluated with a sensitivity analysis. The reliability model has been extended by the results of radiation tests. Design improvements, like redundant optical transmission, have been implemented in an iterative process. The proposed system is compliant with the reliability requirements. The model uncertainties are given by the limited knowledge of the thresholds levels of the superconductive magnets and of the locations of the losses along the ring. The implemented model allows modifications of the system, following the measuring of the hazard rates during the LHC life. It can also provide reference numbers to other accelerators which will implement similar technologies. (author)

  4. The LHC beam loss monitoring system's real-time data analysis card

    Energy Technology Data Exchange (ETDEWEB)

    Zamantzas, C.; Dehning, B.; Effinger, E.; Ferioli, G.; Guaglio, G.; Leitner, R. [Conseil Europeen pour la Recherche Nucleaire, Geneve (Switzerland)

    2005-07-01

    The BLM (Beam Loss Monitoring) system has to prevent the superconducting magnets from being quenched and protect the machine components against damages making it one of the most critical elements for the protection of the LHC. The complete system consists of 3600 detectors, placed at various locations around the ring, tunnel electronics, which are responsible for acquiring, digitizing, and transmitting the data, and surface electronics, which receive the data via 2 km optical data links, process, analyze, store, and issue warning and abort triggers. At those surface units, named BLMTCs, the backbone on each of them is an FPGA (field programmable gate array) which treats the loss signals collected from 16 detectors. It takes into account the beam energy and keeps 192 running sums giving loss durations of up to the last 84 seconds before it compares them with thresholds uniquely programmable for each detector. In this paper, the BLMTC's design is explored giving emphasis to the strategies followed in combining the data from the integrator and the ADC, and in keeping the running sums updated in a way that gives the best compromise between memory needs, computation, and approximation error. (authors)

  5. A read-out system for online monitoring of intensity and position of beam losses in electron linacs

    International Nuclear Information System (INIS)

    In particle accelerators, beam loss position monitors (BLPM) are diagnostic systems revealing an interaction of the beam with the vacuum chamber or with other obstacles. They primarily measure the intensity of the beam loss by detecting particles from the electromagnetic shower in the proximity of the beam pipe. Through an appropriate detector configuration, this measurement also provides information about the longitudinal position of the beam loss along the beam line. This paper presents the design and performance of the BLPM system originally proposed and tested at the SPARC accelerator at Frascati National Laboratory (LNF) of INFN and, later, further developed in the framework of a collaboration with the FERMI-Elettra project at Sincrotrone Trieste. For both facilities, the monitoring of beam losses in permanent magnet undulators is of particular interest. The BLPM consists of quartz fibers stretched in parallel to the beam axis which collect the Cherenkov light generated by charged particles traversing them. Multi-pixel photon counters are used to transform the light into a proportional time dependent electric signal. The use of these simple but highly sensitive photon detectors instead of traditional photomultiplier tubes is an innovation over previous BLPM implementations. It has allowed the development of a compact and reliable read-out system at low cost. In daily use, the system provides information to machine protection and control systems for beam transport monitoring and optimization.

  6. LHC beam loss pattern recognition

    CERN Document Server

    Marsili, A; Puzo, P

    2011-01-01

    One of the systems protecting CERN’s Large Hadron Collider (LHC) is the Beam Loss Monitoring system (BLM). More than 3600 monitors are installed around the ring. The beam losses are permanently integrated over 12 different time intervals (from 40 microseconds to 84 seconds). When any loss exceeds the thresholds defined for the integration window, the beam is removed from the machine. Understanding the origin of a beam loss is crucial for machine operation, as it can help to avoid a repetition of the same scenario. The signals read from given monitors can be considered as entries of a vector. This article presents how a loss map of unknown cause can be decomposed using vector based analysis derived from well-known loss scenarios. The algorithms achieving this decomposition are described, as well as the accuracy of the results.

  7. Beam Loss in Linacs

    CERN Document Server

    Plum, M A

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  8. Comparative test results of various beam loss monitors in preparation for LHC

    CERN Document Server

    Bosser, Jacques

    2000-01-01

    Beam loss detectors will play an important role in the protection of the superconducting LHC magnets. Different types of detectors have been tested in the SPS ring and secondary beam lines with a view to their possible use for this application. This paper describes the measurements made with: microcalorimeters at cryogenic temperatures, PIN diodes, ionisation chambers, scintillators, and ACEMs. Measurements made using proton beams showing their relative sensitivities, linearities in counting or analog mode and minimum detection level will be presented.

  9. Detection of Equipment Faults Before Beam Loss

    CERN Document Server

    Galambos, J

    2016-01-01

    High-power hadron accelerators have strict limits on fractional beam loss. In principle, once a high-quality beam is set up in an acceptable state, beam loss should remain steady. However, in practice, there are many trips in operational machines, owing to excessive beam loss. This paper deals with monitoring equipment health to identify precursor signals that indicate an issue with equipment that will lead to unacceptable beam loss. To this end, a variety of equipment and beam signal measurements are described. In particular, several operational examples from the Spallation Neutron Source (SNS) of deteriorating equipment functionality leading to beam loss are reported.

  10. Improvement of PLC-based data acquisition system for beam loss monitors of the J-PARC main ring

    International Nuclear Information System (INIS)

    A data acquisition system of the beam loss monitor of J-PARC Main Ring consists of the combination of Programmable Logic Controller (PLC). The system needs the high speed response to an external trigger. So we use high speed data acquisition modules to get output data from the beam loss monitor. Triggered by an external trigger pulse, the system begins to acquire the data with some pre-defined intervals by the signal which the system itself generates. We use the new type of a CPU module of PLC, in which an embedded EPICS system on the Linux OS. With the new type of a CPU module, the data acquisition system becomes simpler. This paper reports the state of development and the result in operation. (author)

  11. In situ radiation test of silicon and diamond detectors operating in superfluid helium and developed for beam loss monitoring

    Science.gov (United States)

    Kurfürst, C.; Dehning, B.; Sapinski, M.; Bartosik, M. R.; Eisel, T.; Fabjan, C.; Rementeria, C. A.; Griesmayer, E.; Eremin, V.; Verbitskaya, E.; Zabrodskii, A.; Fadeeva, N.; Tuboltsev, Y.; Eremin, I.; Egorov, N.; Härkönen, J.; Luukka, P.; Tuominen, E.

    2015-05-01

    As a result of the foreseen increase in the luminosity of the Large Hadron Collider, the discrimination between the collision products and possible magnet quench-provoking beam losses of the primary proton beams is becoming more critical for safe accelerator operation. We report the results of ongoing research efforts targeting the upgrading of the monitoring system by exploiting Beam Loss Monitor detectors based on semiconductors located as close as possible to the superconducting coils of the triplet magnets. In practice, this means that the detectors will have to be immersed in superfluid helium inside the cold mass and operate at 1.9 K. Additionally, the monitoring system is expected to survive 20 years of LHC operation, resulting in an estimated radiation fluence of 1×1016 proton/cm2, which corresponds to a dose of about 2 MGy. In this study, we monitored the signal degradation during the in situ irradiation when silicon and single-crystal diamond detectors were situated in the liquid/superfluid helium and the dependences of the collected charge on fluence and bias voltage were obtained. It is shown that diamond and silicon detectors can operate at 1.9 K after 1×1016 p/cm2 irradiation required for application as BLMs, while the rate of the signal degradation was larger in silicon detectors than in the diamond ones. For Si detectors this rate was controlled mainly by the operational mode, being larger at forward bias voltage.

  12. Calculation of abort thresholds for the Beam Loss Monitoring System of the Large Hadron Collider at CERN

    CERN Document Server

    Nemcic, Martin; Dehning, Bernd

    The Beam Loss Monitoring (BLM) System is one of the most critical machine protection systems for the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), Switzerland. Its main purpose is to protect the superconducting magnets from quenches and other equipment from damage by requesting a beam abort when the measured losses exceed any of the predefined threshold levels. The system consist of circa 4000 ionization chambers which are installed around the 27 kilometres ring (LHC). This study aims to choose a technical platform and produce a system that addresses all of the limitations with the current system that is used for the calculation of the LHC BLM abort threshold values. To achieve this, a comparison and benchmarking of the Java and .NET technical platforms is performed in order to establish the most suitable solution. To establish which technical platform is a successful replacement of the current abort threshold calculator, comparable prototype systems in Java and .NET we...

  13. Overview of LHC Beam Loss Measurements

    CERN Document Server

    Dehning, B; Effinger, E; Emery, J; Fadakis, E; Holzer, E B; Jackson, S; Kruk, G; Kurfuerst, C; Marsili, A; Misiowiec, M; Nebot Del Busto, E; Nordt, A; Priebe, A; Roderick, C; Sapinski, M; Zamantzas, C; Grishin, V; Griesmayer, E

    2011-01-01

    The LHC beam loss monitoring system provides measurements with an update rate of 1 Hz and high time resolution data by event triggering. These informations are used for the initiation of beam aborts, fixed displays and the off line analysis. The analysis of fast and localized loss events resulted in the determination of its rate, duration, peak amplitudes, its scaling with intensity, number of bunches and beam energy. The calibration of the secondary shower beam loss signal in respect to the needed beam energy deposition to quench the magnet coil is addressed at 450GeV and 3.5T eV . The adjustment of collimators is checked my measuring the loss pattern and its variation in the collimation regions of the LHC. Loss pattern changes during a fill allow the observation of non typical fill parameters.

  14. Short bunched beam monitor

    International Nuclear Information System (INIS)

    In order to monitor the short bunched beam, two types of monitors were developed and tested. A core monitor using a Co-based amorphous core which has high μ characteristics and high frequency response can be used as a non-destructive current monitor for the beam in the range of 1ns to several μs pulse width. A wall current monitor designed carefully has been also tested. The wall current monitor has measured the beam shape with the pulse width of 200ps or less. In this paper the characteristics and overall performance of these monitors are described. (author)

  15. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  16. A novel digitization scheme with FPGA-base TDC for beam loss monitors operating at cryogenic temperature

    International Nuclear Information System (INIS)

    Recycling integrators are common current-to-frequency converting circuits for measurements of low current such as that produced by Fermilab's cryogenic ionization chambers. In typical digitization/readout schemes, a counter is utilized to accumulate the number of pulses generated by the recycling integrator to adequately digitize the total charge. In order to calculate current with reasonable resolution (e.g., 7-8 bits), hundreds of pulses must be accumulated which corresponds to a long sampling period, i.e., a very low sampling rate. In our new scheme, an FPGA-based Time-to-Digital Convertor (TDC) is utilized to measure the time intervals between the pulses output from the recycling integrator. Using this method, a sample point of the current can be made with good resolution (>10 bits) for each pulse. This effectively increases the sampling rates by hundreds of times for the same recycling integrator front-end electronics. This scheme provides a fast response to the beams loss and is potentially suitable for accelerator protection applications. Moreover, the method is also self-zero-suppressed, i.e., it produces more data when the beam loss is high while it produces significantly less data when the beam loss is low.

  17. Cavity beam position monitors

    International Nuclear Information System (INIS)

    Beam-based alignment and feedback systems are essential for the operation of future linear colliders and free electron lasers. A certain number of beam position monitors with a resolution in the submicron range are needed at selected locations. Most beam position monitors detect the electric or the magnetic field excited by a beam of charged particles at different locations around the beam pipe. In resonant monitors, however, the excitation of special field configurations by an off-center beam is detected. These structures offer a large signal per micron displacement. This paper is an attempt to summarize the fundamental characteristics of resonant monitors, their advantages and shortcomings. Emphasis will be on the design of cylindrical cavities, in particular on the estimation of expected signals, of resolution limits and the resulting beam distortion. This includes also a short introduction into numerical methods. Fabrication, tuning, and other practical problems will be reviewed briefly. Finally, some resonant devices used for beam position diagnostics will be discussed and listed

  18. Preliminary comments about beam loss

    Energy Technology Data Exchange (ETDEWEB)

    Groom, D.

    1985-10-01

    A variety of beam loss questions are being investigated. They affect several design issues, ranging from machine-associated background in the detectors to the radiation lifetime of the main-ring magnets: (1) Muons. Oppositely directed muon beams from prompt muon production, primary meson decay, and a variety of other processes radiate from each IR. If they were not fanned by the insertion dipoles, the beams would be sufficiently intense and energetic that they would present a radiation hazard even after penetrating 2 km of soil or rock. (2) Machine-associated background in the IR`s. About 30 mb of the total cross section is elastic or quasi-elastic, and most of the protons are in a Gaussian spot with sigma = 9 mr. These particles are well within the machine acceptance, but there is a grey area in the tail of the distributions in which the scattered particles `almost` remain in orbit - they continue for some distance but eventually hit a wall. (3) Cryogenic load. This problem has been addressed to some degree in the RDS, but considerably more detail is needed. It appears that a very large fraction of the inelastic particle energy will be deposited here. (4) Radiation damage in the ring. The lifetime of both magnets and electronics in the tunnel might be limited by radiation due to particle loss. Early results are not reassuring. Tevatron measurements, reported to the authors by John Elias, indicate that most of the tunnel background comes from particle loss due to beam-gas collisions.

  19. Beam Position Monitor Engineering

    International Nuclear Information System (INIS)

    The design of beam position monitors often involves challenging system design choices. Position transducers must be robust, accurate, and generate adequate position signal without unduly disturbing the beam. Electronics must be reliable and affordable, usually while meeting tough requirements on precision. accuracy, and dynamic range. These requirements may be difficult to achieve simultaneously, leading the designer into interesting opportunities for optimization or compromise. Some useful techniques and tools are shown. Both finite element analysis and analytic techniques will be used to investigate quasi-static aspects of electromagnetic fields such as the impedance of and the coupling of beam to striplines or buttons. Finite-element tools will be used to understand dynamic aspects of the electromagnetic fields of beams, such as wake-fields and transmission-line and cavity effects in vacuum-to-air feed through. Mathematical modeling of electrical signals through a processing chain will be demonstrated, in particular to illuminate areas where neither a pure time-domain nor a pure frequency-domain analysis is obviously advantageous. Emphasis will be on calculational techniques, in particular on using both time-domain and frequency domain approaches to the applicable parts of interesting problems

  20. In Process Beam Monitoring

    Science.gov (United States)

    Steen, W. M.; Weerasinghe, V. M.

    1986-11-01

    The industrial future of lasers in material processing lies in the combination of the laser with automatic machinery. One possible form of such a combination is an intelligent workstation which monitors the process as it occurs and adjusts itself accordingly, either by self teaching or by comparison to a process data bank or algorithm. In order to achieve this attractive goal in-process signals are required. Two devices are described in this paper. One is the Laser Beam Analyser which is now maturing into a second generation with computerised output. The other is the Acoustic Mirror, a totally novel analytic technique, not yet fully understood, but which nevertheless can act as a very effective process monitor.

  1. Electrostatic beam-position monitor

    CERN Multimedia

    CERN PhotoLab

    1969-01-01

    Electrostatic beam-position monitor installed in its final location (bake-out cover removed). The ISR will contain about 110 of these monitors. Their accuracy is better than 1 mm, their band width about 1 MHz.

  2. Monitoring Dosimetric Impact of Weight Loss With Kilovoltage (KV) Cone Beam CT (CBCT) During Parotid-Sparing IMRT and Concurrent Chemotherapy

    International Nuclear Information System (INIS)

    Purpose: Parotid-sparing head-and-neck intensity-modulated radiotherapy (IMRT) can reduce long-term xerostomia. However, patients frequently experience weight loss and tumor shrinkage during treatment. We evaluate the use of kilovoltage (kV) cone beam computed tomography (CBCT) for dose monitoring and examine if the dosimetric impact of such changes on the parotid and critical neural structures warrants replanning during treatment. Methods and materials: Ten patients with locally advanced oropharyngeal cancer were treated with contralateral parotid-sparing IMRT concurrently with platinum-based chemotherapy. Mean doses of 65 Gy and 54 Gy were delivered to clinical target volume (CTV)1 and CTV2, respectively, in 30 daily fractions. CBCT was prospectively acquired weekly. Each CBCT was coregistered with the planned isocenter. The spinal cord, brainstem, parotids, larynx, and oral cavity were outlined on each CBCT. Dose distributions were recalculated on the CBCT after correcting the gray scale to provide accurate Hounsfield calibration, using the original IMRT plan configuration. Results: Planned contralateral parotid mean doses were not significantly different to those delivered during treatment (p > 0.1). Ipsilateral and contralateral parotids showed a mean reduction in volume of 29.7% and 28.4%, respectively. There was no significant difference between planned and delivered maximum dose to the brainstem (p = 0.6) or spinal cord (p = 0.2), mean dose to larynx (p = 0.5) and oral cavity (p = 0.8). End-of-treatment mean weight loss was 7.5 kg (8.8% of baseline weight). Despite a ≥10% weight loss in 5 patients, there was no significant dosimetric change affecting the contralateral parotid and neural structures. Conclusions: Although patient weight loss and parotid volume shrinkage was observed, overall, there was no significant excess dose to the organs at risk. No replanning was felt necessary for this patient cohort, but a larger patient sample will be investigated

  3. Monitoring Dosimetric Impact of Weight Loss With Kilovoltage (KV) Cone Beam CT (CBCT) During Parotid-Sparing IMRT and Concurrent Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Kean Fatt, E-mail: hokeanfatt@hotmail.com [Academic Radiation Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom); Marchant, Tom; Moore, Chris; Webster, Gareth; Rowbottom, Carl [North Western Medical Physics, The Christie NHS Foundation Trust, Manchester (United Kingdom); Penington, Hazel [Wade Radiotherapy Research Centre, The Christie NHS Foundation Trust, Manchester (United Kingdom); Lee, Lip; Yap, Beng; Sykes, Andrew; Slevin, Nick [Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom)

    2012-03-01

    Purpose: Parotid-sparing head-and-neck intensity-modulated radiotherapy (IMRT) can reduce long-term xerostomia. However, patients frequently experience weight loss and tumor shrinkage during treatment. We evaluate the use of kilovoltage (kV) cone beam computed tomography (CBCT) for dose monitoring and examine if the dosimetric impact of such changes on the parotid and critical neural structures warrants replanning during treatment. Methods and materials: Ten patients with locally advanced oropharyngeal cancer were treated with contralateral parotid-sparing IMRT concurrently with platinum-based chemotherapy. Mean doses of 65 Gy and 54 Gy were delivered to clinical target volume (CTV)1 and CTV2, respectively, in 30 daily fractions. CBCT was prospectively acquired weekly. Each CBCT was coregistered with the planned isocenter. The spinal cord, brainstem, parotids, larynx, and oral cavity were outlined on each CBCT. Dose distributions were recalculated on the CBCT after correcting the gray scale to provide accurate Hounsfield calibration, using the original IMRT plan configuration. Results: Planned contralateral parotid mean doses were not significantly different to those delivered during treatment (p > 0.1). Ipsilateral and contralateral parotids showed a mean reduction in volume of 29.7% and 28.4%, respectively. There was no significant difference between planned and delivered maximum dose to the brainstem (p = 0.6) or spinal cord (p = 0.2), mean dose to larynx (p = 0.5) and oral cavity (p = 0.8). End-of-treatment mean weight loss was 7.5 kg (8.8% of baseline weight). Despite a {>=}10% weight loss in 5 patients, there was no significant dosimetric change affecting the contralateral parotid and neural structures. Conclusions: Although patient weight loss and parotid volume shrinkage was observed, overall, there was no significant excess dose to the organs at risk. No replanning was felt necessary for this patient cohort, but a larger patient sample will be investigated

  4. A new beam loss detector for low-energy proton and heavy-ion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhengzheng, E-mail: liuz@frib.msu.edu; Crisp, Jenna; Russo, Tom; Webber, Robert; Zhang, Yan

    2014-12-11

    The Facility for Rare Isotope Beams (FRIB) to be constructed at Michigan State University shall deliver a continuous, 400 kW heavy ion beam to the isotope production target. This beam is capable of inflicting serious damage on accelerator components, e.g. superconducting RF accelerating cavities. A Beam Loss Monitoring (BLM) System is essential for detecting beam loss with sufficient sensitivity and promptness to inform the machine protection system (MPS) and operations personnel of impending dangerous losses. Radiation transport simulations reveal shortcomings in the use of ionization chambers for the detection of beam losses in low-energy, heavy-ion accelerators. Radiation cross-talk effects due to the folded geometry of the FRIB LINAC pose further complications to locating specific points of beam loss. We propose a newly developed device, named the Loss Monitor Ring (LMR), to be implemented upstream of each FRIB cryomodule, as part of the direct loss monitoring system to fulfill the needs of machine protection. - Highlights: • Traditional BLM is not effective for beam loss monitoring at FRIB low energy linac segments. • We developed LMR to intercept a small portion of beam loss and output voltage signals. • We made a prototype LMR and demonstrated its functionality to monitor small beam losses. • The LMR is very sensitive for small beam losses and is independent of beam current. • The LMR is especially useful for loss monitoring at low energy ion/proton accelerators.

  5. A new beam loss detector for low-energy proton and heavy-ion accelerators

    International Nuclear Information System (INIS)

    The Facility for Rare Isotope Beams (FRIB) to be constructed at Michigan State University shall deliver a continuous, 400 kW heavy ion beam to the isotope production target. This beam is capable of inflicting serious damage on accelerator components, e.g. superconducting RF accelerating cavities. A Beam Loss Monitoring (BLM) System is essential for detecting beam loss with sufficient sensitivity and promptness to inform the machine protection system (MPS) and operations personnel of impending dangerous losses. Radiation transport simulations reveal shortcomings in the use of ionization chambers for the detection of beam losses in low-energy, heavy-ion accelerators. Radiation cross-talk effects due to the folded geometry of the FRIB LINAC pose further complications to locating specific points of beam loss. We propose a newly developed device, named the Loss Monitor Ring (LMR), to be implemented upstream of each FRIB cryomodule, as part of the direct loss monitoring system to fulfill the needs of machine protection. - Highlights: • Traditional BLM is not effective for beam loss monitoring at FRIB low energy linac segments. • We developed LMR to intercept a small portion of beam loss and output voltage signals. • We made a prototype LMR and demonstrated its functionality to monitor small beam losses. • The LMR is very sensitive for small beam losses and is independent of beam current. • The LMR is especially useful for loss monitoring at low energy ion/proton accelerators

  6. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    International Nuclear Information System (INIS)

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7-MeV and current of 100-mA operating in either a pulsed or cw mode. Of key importance to the commissioning and operations effort is the Beam Position Monitor system (BPM). The LEDA BPM system uses five micro-stripline beam position monitors processed by log ratio processing electronics with data acquisition via a series of custom TMS32OC40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of the system, the log ratio processing, and the system calibration technique. This paper will also cover the DSP system operations and their interaction with the main accelerator control system

  7. Beam Position Monitoring at CLIC

    CERN Document Server

    Prochnow, J

    2003-01-01

    At the European Organisation for Nuclear Research CERN in Geneva, Switzerland the design of the Compact LInear Collider (CLIC) for high energy physics is studied. To achieve the envisaged high luminosity the quadrupole magnets and radio-frequency accelerating structures have to be actively aligned with micron precision and submicron resolution. This will be done using beam-based algorithms which rely on beam position information inside of quadrupoles and accelerating structures. After a general introduction to the CLIC study and the alignment algorithms, the concept of the interaction between beams and radio-frequency structures is given. In the next chapter beam measurements and simulations are described which were done to study the performance of cavity beam position monitors (BPM). A BPM design is presented which is compatible with the multi-bunch operation at CLIC and could be used to align the quadrupoles. The beam position inside the accelerating structures will be measured by using the structures thems...

  8. Beam losses in heavy ion drivers

    CERN Document Server

    Mustafin, E R; Hofmann, I; Spiller, P J

    2002-01-01

    While beam loss issues have hardly been considered in detail for heavy ion fusion scenarios, recent heavy ion machine developments in different labs (European Organization for Nuclear Research (CERN), Gesellschaft fur Schwerionenforschung (GSI), Institute for Theoretical and Experimental Physics (ITEP), Relativistic Heavy-Ion Collider (RHIC)) have shown the great importance of beam current limitations due to ion losses. Two aspects of beam losses in heavy ion accelerators are theoretically considered: (1) secondary neutron production due to lost ions, and (2) vacuum pressure instability due to charge exchange losses. Calculations are compared and found to be in good agreement with measured data. The application to a Heavy-Ion Driven Inertial Fusion (HIDIF) scenario is discussed. 12 Refs.

  9. Neutral Beam Ion Loss Modeling for NSTX

    International Nuclear Information System (INIS)

    A numerical model, EIGOL, has been developed to calculate the loss rate of neutral beam ions from NSTX and the resultant power density on the plasma facing components. This model follows the full gyro-orbit of the beam ions, which can be a significant fraction of the minor radius. It also includes the three-dimensional structure of the plasma facing components inside NSTX. Beam ion losses from two plasma conditions have been compared: β = 23%, q0 = 0.8, and β = 40%, q0 = 2.6. Global losses are computed to be 4% and 19%, respectively, and the power density on the rf antenna is near the maximum tolerable levels in the latter case

  10. Micromegas neutron beam monitor neutronics.

    Science.gov (United States)

    Stephan, Andrew C; Miller, Laurence F

    2005-01-01

    The Micromegas is a type of ionising radiation detector that consists of a gas chamber sandwiched between two parallel plate electrodes, with the gas chamber divided by a Frisch grid into drift and amplification gaps. Investigators have applied it to a number of different applications, such as charged particle, X-ray and neutron detection. A Micromegas device has been tested as a neutron beam monitor at CERN and is expected to be used for that purpose at the Spallation Neutron Source (SNS) under construction in Oak Ridge, TN. For the Micromegas to function effectively as neutron beam monitor, it should cause minimal disruption to the neutron beam in question. Specifically, it should scatter as few neutrons as possible and avoid neutron absorption when it does not contribute to generating useful information concerning the neutron beam. Here, we present the results of Monte Carlo calculations of the effect of different types of wall materials and detector gases on neutron beams and suggest methods for minimising disruption to the beam. PMID:16381746

  11. 2014 Joint International Accelerator School: Beam Loss and Accelerator Protection

    CERN Document Server

    JAS - Joint US-CERN-Japan-Russia Accelerator School

    2016-01-01

    Many particle accelerators operate with very high beam power and very high energy stored in particle beams as well as in magnet systems. In the future, the beam power in high intensity accelerators will further increase. The protection of the accelerator equipment from the consequences of uncontrolled release of the energy is essential. This was the motivation for organizing a first school on beam losses and accelerator protection (in general referred to as machine protection). During the school the methods and technologies to identify, mitigate, monitor and manage the technical risks associated with the operation of accelerators with high-power beams or subsystems with large stored energy were presented. At the completion of the school the participants should have been able to understand the physical phenomena that can damage machine subsystems or interrupt operations and to analyze an accelerator facility to produce a register of technical risks and the corresponding risk mitigation and management strategie...

  12. The ATLAS Diamond Beam Monitor

    CERN Document Server

    Schaefer, Douglas; The ATLAS collaboration

    2015-01-01

    After the first three years of the LHC running the ATLAS experiment extracted it's pixel detector system to refurbish and re-position the optical readout drivers and install a new barrel layer of pixels. The experiment has also taken advantage of this access to also install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes were assembled based on chemical vapour deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This talk will describe the lessons learned in construction and commissioning of the ATLAS x Diamond Beam Monitor (DBM). We will show results from the construction quality assurance tests, commissioning performance, including results from cosmic ray running in early 2015 and also expected first results from LHC run 2 collisions.

  13. Identification of LHC beam loss mechanism : a deterministic treatment of loss patterns

    CERN Document Server

    Marsili, Aurélien

    CERN's Large Hadron Collider (LHC) is the largest machine ever built, with a total circumference of 26.7 km; and it is the most powerful accelerator ever, both in beam energy and beam intensity. The main magnets are superconducting, keeping the particles into two counter circulating beams, which collide in four interaction points. CERN and the LHC will be described in chap. 1. The superconducting magnets of the LHC have to be protected against particle losses. Depending on the number of lost particles, the coils of the magnets will become normal conducting and/or will be damaged. To avoid these events a beam loss monitoring (BLM) system was installed to measure the particle loss rates. If the predefined safe thresholds of loss rates are exceeded, the beams are directed out of the accelerator ring towards the beam dump. The detectors of the BLM system are mainly ionization chambers located outside of the cryostats. In total, about 3500 ionisation chambers are installed. Further challenges include the high dyna...

  14. The ATLAS beam conditions monitor

    CERN Document Server

    Mikuz, M; Dolenc, I; Kagan, H; Kramberger, G; Frais-Kölbl, H; Gorisek, A; Griesmayer, E; Mandic, I; Pernegger, H; Trischuk, W; Weilhammer, P; Zavrtanik, M

    2006-01-01

    The ATLAS beam conditions monitor is being developed as a stand-alone device allowing to separate LHC collisions from background events induced either on beam gas or by beam accidents, for example scraping at the collimators upstream the spectrometer. This separation can be achieved by timing coincidences between two stations placed symmetric around the interaction point. The 25 ns repetition of collisions poses very stringent requirements on the timing resolution. The optimum separation between collision and background events is just 12.5 ns implying a distance of 3.8 m between the two stations. 3 ns wide pulses are required with 1 ns rise time and baseline restoration in 10 ns. Combined with the radiation field of 10/sup 15/ cm/sup -2/ in 10 years of LHC operation only diamond detectors are considered suitable for this task. pCVD diamond pad detectors of 1 cm/sup 2/ and around 500 mum thickness were assembled with a two-stage RF current amplifier and tested in proton beam at MGH, Boston and SPS pion beam at...

  15. Fast Beam Current Change Monitor for the LHC

    CERN Document Server

    Kral, Jan

    Stringent demands on the LHC safety and protection systems require improved methods of detecting fast beam losses. The Fast Beam Current Transformer (FBCT) is a measurement instrument, providing information about bunch-to-bunch intensity of the accelerated beam. This thesis describes the development of a new protection system based on the FBCT signal measurements. This system, the Fast Beam Current Change Monitor (FBCCM), measures the FBCT signal in a narrow frequency band and computes time derivation of the beam signal magnitude. This derivation is proportional to the beam losses. When the losses exceed a certain level, the FBCCM requests a beam dump in order to protect the LHC. The LHC protection will be ensured by four FBCCMs which will be installed into the LHC in July 2014. Six FBCCMs have been already constructed and their characteristics were measured with satisfactory results. The FBCCMs were tested by a laboratory simulation of the real LHC environment.

  16. LHC Beam Instrumentation: Beam Loss and Tune Measurements (3/3)

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The LHC is equipped with a full suite of sophisticated beam instrumentation which has been essential for rapid commissioning, the safe increase in total stored beam power and the understanding of machine optics and accelerator physics phenomena. These lectures will introduce these systems and comment on their contributions to the various stages of beam operation. They will include details on: the beam position system and its use for real-time global orbit feedback; the beam loss system and its role in machine protection; total and bunch by bunch intensity measurements; tune measurement and feedback; diagnostics for transverse beam size measurements, abort gap monitoring and longitudinal density measurements. Issues and problems encountered along the way will also be discussed together with the prospect for future upgrades.

  17. Identification of LHC beam loss mechanism: a deterministic treatment of loss patterns

    International Nuclear Information System (INIS)

    The goal of this work was to identify patterns in the beam loss profiles, both in their spatial distribution and time evolution. CERN's Large Hadron Collider (LHC) is the largest device ever built, with a total circumference of 26.7 km; and it is the most powerful accelerator ever, both in beam energy and beam intensity. The main magnets are superconducting, and contain the particles into two counter circulating beams which collide in four interaction points. CERN and the LHC will be described in chapter 1. The superconducting magnets of the LHC have to be protected against particle losses. Depending on the number of lost particles, the coils of the magnets could become normal conducting and/or will be damaged. To avoid these events a beam loss monitoring (BLM) system was installed to measure the particle loss rates. If the predefined safe thresholds of loss rates are exceeded, the beams are directed out of the accelerator ring towards the beam dump. The detectors of the BLM system are mainly ionization chambers located outside of the cryostats. In total, about 3600 ionisation chambers are installed. Further challenges include the high dynamical range of losses (chamber currents ranging between 2 pA and 1 mA). The BLM system will be further described in chapter 2. The subject of this thesis is to study the loss patterns and nd the origin of the losses in a deterministic way, by comparing measured losses to well understood loss scenarios. This is done through a case study: different techniques were used on a restrained set of loss scenarios, as a proof of concept of the possibility to extract information from a loss profile. Finding the origin of the losses should allow acting in response. A justification of the doctoral work will be given at the end of chapter 2. This thesis will then focus on the theoretical understanding and the implementation of the decomposition of a measured loss profile as a linear combination of the reference scenarios; and the evaluation of

  18. Calibration of waveguide beam position monitors

    CERN Document Server

    Kamps, T

    2000-01-01

    To ensure overlap between the photon beam and electron beam at the SASE-FEL at the TESLA Test Facility, several position-sensitive diagnostics components are installed along the beamline of the FEL. For the undulator part, a new type of waveguide beam position monitors (BPMs) is designed, tested, and installed inside the beam pipe of one undulator module. This paper proposes a method to calibrate these monitors with beam-based measurements

  19. Beam intensity monitoring for the external proton beam at LAMPF

    International Nuclear Information System (INIS)

    Three different intensity monitors were tested in the external proton beam at LAMPF, and together cover the entire range of beam currents available. A 800 kg Faraday cup was installed and used to measure the absolute intensity to better than 1 percent for beam currents up to several nanoamperes. A high gain ion chamber was used as part of the calibration procedure for the Faraday cup, and was found to be useful when monitoring very small beam intensities, being reliable down to the few picoampere level. A secondary emission monitor was also tested, calibrated, and found to be trustworthy only for beams of greater than 50 pA intensity. (auth)

  20. Development of proton beam monitoring devices

    International Nuclear Information System (INIS)

    We develop an 1 channel ionization chamber for beam monitoring system of KOMAC 20/100 MeV proton accelerator with a crystal scintillator, and try to make Multi Functional detectors, which can cover wide range of proton current. After the development, it is possible to provide the beam information to KOMAC beam users. We also develop a fast neutron detector system to detect the proton recoil by the neutron in the beam line. This system can provide the neutron dose information to beam user for safety. The followings are our major study 1) Beam profile and energy monitoring by using scintillators 2) Development of 32 channel Charge integration Embedded DAQ board 3) 1 channel gas scintillation detector for pulse beam monitoring 4) Development of fast neutron detector. Results Our major achievements are as follows ; 1) XY distribution scanning of proton beam by using LYSO crystal scintillator, 2) Development of a 32 channel Charge integration Embedded DAQ board and test it on beam line, 3) Development of 1 channel gas scintillation detector for pulse beam monitoring and test at KOMAC beam line. 4) Development of fast neutron detectors such as liquid scintillator and stilbene and measured neutron at beam line. The most important achievements of this research are ; 1) We measured the timing structure of proton beam by using 1 ch gas scintillation detector, and 2) it was possible to scanning the XY distribution of proton beam at real time

  1. Tevatron Beam Position Monitor Upgrade

    CERN Document Server

    Wolbers, Stephen; Barker, B; Bledsoe, S; Boes, T; Bowden, Mark; Cancelo, Gugstavo I; Dürling, G; Forster, B; Haynes, B; Hendricks, B; Kasza, T; Kutschke, Robert K; Mahlum, R; Martens, Michael A; Mengel, M; Olsen, M; Pavlicek, V; Pham, T; Piccoli, Luciano; Steimel, Jim; Treptow, K; Votava, Margaret; Webber, Robert C; West, B; Zhang, D

    2005-01-01

    The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance.

  2. Higher-order-mode damper as beam-position monitors

    International Nuclear Information System (INIS)

    In the framework of this thesis a beam-position monitor was developed, which can only because of the signals from the HOM dampers of a linear-accelerator structure determine the beam position with high accuracy. For the unique determination of the beam position in the plane a procedure was developed, which uses the amplitudes and the start-phase difference between a dipole mode and a higher monopole mode. In order tocheck the suitability of the present SBLC-HOM damper as beam position monitor three-dimensional numerical field calculations in the frequency and time range and measurements on the damper cell were performed. For the measurements without beam a beam simulator was constructed, which allows computer-driven measurements with variable depositions of the simulated beam with a resolution of 1.23 μm. Because the complete 6 m long, 180-cell accelerator structure was not available for measurements and could also with the available computers not be three-dimensionally simulated simulated, a one-dimensional equivalent-circuit based model of the multi-cell was studied. The equivalent circuits with 879 concentrated components regards the detuning from cell to cell, the cell losses, the damper losses, and the beam excitation in dependence on the deposition. the measurements and simulations let a resolution of the ready beam-position monitor on the 180-cell in the order of magnitude of 1-10 μm and a relative accuracy smaller 6.2% be expected

  3. The Electro-Optic Beam Position Monitor

    CERN Document Server

    Doherty, James

    2013-01-01

    This reports outlines the development of a new ultra-wideband electro-optic beam position monitor (EO-BPM) for use in the Large Hadron Collider (LHC) which utilises birefringent crystals and the Pockels effect to monitor beam position. The physical principles behind the operation of the device and tested topology, which incorporates two Lithium Tantalate crystals, is discussed.

  4. Beam Profile Monitors in the Nlcta

    OpenAIRE

    Nantista, C.; Adolphsen, C.; Brown, R L; Fuller, R.; Rifkin, J.

    2000-01-01

    The transverse current profile in the Next Linear Collider Test Accelerator (NLCTA) electron beam can be monitored at several locations along the beam line by means of profile monitors. These consist of insertable phosphor screens, light collection and transport systems, CID cameras, a frame-grabber, and PC and VAX based image analysis software. In addition to their usefulness in tuning and steering the accelerator, the profile monitors are utilized for emittance measurement. A description of...

  5. Beam Loss Control for the Fermilab Main Injector

    CERN Document Server

    Brown, Bruce C

    2013-01-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Losses were at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  6. Beam test of wire scanner beam size monitor

    International Nuclear Information System (INIS)

    A beam size monitor for emittance measurement is required to have around 10μm resolution for injector linac, and to have a few tenth μm resolution for an extracted beam from a damping ring in Accelerator Test Facility (ATF). A wire scanner is a one of the candidate of a beam size monitor with a high resolution. The design and development study of the wire scanning stage has been done. The beam test using Tohoku 300MeV Linac was done and the emittance was measured by this wire scanner. A detection of beam size signal was done by a scintillator gamma detector placed at downstream of the wire stage. All of the measurements are taken by the computer. The beam test results are described. (author)

  7. Beam steering using quadrupoles as position monitors

    International Nuclear Information System (INIS)

    An algorithm is proposed to center the beam in the quadrupoles of a transfer line, by changing the focusing strength of a quadrupole and observing the resulting position shift on a monitor downstream. The observed position shift depends linearly on the beam position offset in the quadrupole, provided the phase advance between the quadrupole and the monitor is not a multiple of π. The same monitor may thus be used to center the beam in several places of the beam line. The centering accuracy depends on the resolution of the monitor and on the quadrupole current increment which can be set in such a way that the beam profile remains sufficiently peaked to determine its mean position

  8. Characterizing and Controlling Beam Losses at the LANSCE Facility

    Energy Technology Data Exchange (ETDEWEB)

    Rybarcyk, Lawrence J. [Los Alamos National Laboratory

    2012-09-12

    The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H{sup +} and 800-MeV H{sup -} beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations in the linac.

  9. Monitor tables for electron beams in radiotherapy

    International Nuclear Information System (INIS)

    The application of electron beams in radiotherapy is still based on tables of monitor units, although 3-D treatment planning systems for electron beams are available. This have several reasons: The need for 3-D treatment planning is not recognized; there is no confidence in the calculation algorithm; Monte-Carlo algorithms are too time-consuming; and the effort necessary to measure basic beam data for 3-D planning is considered disproportionate. However, the increasing clinical need for higher dosimetric precision and for more conformal electron beams leads to the requirement for more sophisticated tables of monitor units. The present paper summarizes and discusses the main aspects concerning the preparation of tables of monitor units for electron beams. The measurement equipment and procedures for measuring basic beam data needed for tables of monitor units for electron beams are described for a standard radiation therapy linac. The design of tables of monitor units for standard electron applicators is presented; this design can be extended for individual electron inserts, to variable applicator surface distances, to oblique beam incidence, and the use of bolus material. Typical data of an Elekta linac are presented in various tables. (orig.)

  10. Luminosity Loss due to Beam Distortion and the Beam-Beam Instability

    CERN Document Server

    Wu, Juhao; Raubenheimer, Tor O; Seryi, Andrei; Sramek, Christopher K

    2005-01-01

    In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ‘banana effect'). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

  11. Beam loss studies for the KEK compact-ERL

    International Nuclear Information System (INIS)

    We performed the beam loss study for the compact Energy Recovery Linac (cERL) at KEK. To this purpose the Touschek effect with intra-beam scattering, the residual gas scattering (elastic and inelastic cases) were examined using existing and modified ELEGANT routines, and developed MATLAB data analysis algorithms to handle the large amount of data that is produced by the program. In addition we performed several simulations to judge the impact of field emission issued from the main cavity. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beam line, which is important for the safety low-emittance and high-current beams operation. The data obtained then are compared with the theoretical estimation to verify the accuracy of the simulations. (author)

  12. Monitor of SC beam profiles

    CERN Multimedia

    1977-01-01

    A high-resolution secondary emission grid for the measurement of SC beam profiles. Modern techniques of metal-ceramic bonding, developed for micro-electronics, have been used in its construction. (See Annual Report 1977 p. 105 Fig. 12.)

  13. ATF beam image monitor software

    International Nuclear Information System (INIS)

    We report about software for the beam image analysis at ATF. We developed image analysis software with a Linux computer. It acquire image data from a video and an IEEE1394 digital camera of the analog. (author)

  14. Beam position monitoring at CLIC

    OpenAIRE

    Prochnow, Jan Erik

    2003-01-01

    At the European Organisation for Nuclear Research CERN in Geneva, Switzerland the design of the Compact LInear Collider (CLIC) for high energy physics is studied. To achieve the envisaged high luminosity the quadrupole magnets and radio-frequency accelerating structures have to be actively aligned with micron precision and submicron resolution. This will be done using beam-based algorithms which rely on beam position information inside of quadrupoles and accelerating structures. After a gener...

  15. Beam Loss Studies for the 2-MW LBNE Proton Beam Line

    Energy Technology Data Exchange (ETDEWEB)

    Drozhdin, A.I.; Childress, S.R.; Mokhov, N.V.; Tropin, I.S.; Zwaska, R.; /Fermilab

    2012-05-01

    Severe limits are put on allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6 x 10{sup 14} protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that loss of a single beam pulse at 2.3 MW will result in a catastrophic event: beam pipe destruction, damaged magnets and very high levels of residual radiation inside and outside the tunnel. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

  16. A Beam Shape Oscillation Monitor for HERA

    International Nuclear Information System (INIS)

    The perfect matching of the injecting beam phase space with the accelerator lattice is a very important problem. Its successful solution allows excluding possible mismatch emittance blow-up and worsening of the beam characteristics, that is necessary to get the highest possible luminosity in hadron accelerators. The mismatch can be controlled by measuring sizes oscillation on the first revolutions of the injected beam at a certain orbit point. Designed for this purpose the construction, acquisition electronics, software controlling of the operation and data processing of such a monitor are described. A first test result with beam is presented

  17. A Beam Shape Oscillation Monitor for HERA

    Science.gov (United States)

    Afanasyev, O. V.; Baluev, A. B.; Gubrienko, K. I.; Merker, E. A.; Wittenburg, K.; Krouptchenkow, I.

    2006-11-01

    The perfect matching of the injecting beam phase space with the accelerator lattice is a very important problem. Its successful solution allows excluding possible mismatch emittance blow-up and worsening of the beam characteristics, that is necessary to get the highest possible luminosity in hadron accelerators. The mismatch can be controlled by measuring sizes oscillation on the first revolutions of the injected beam at a certain orbit point. Designed for this purpose the construction, acquisition electronics, software controlling of the operation and data processing of such a monitor are described. A first test result with beam is presented.

  18. Nondestructive synchronous beam current monitor

    International Nuclear Information System (INIS)

    A fast current transformer is mounted after the deflectors of the Berkeley 88-Inch Cyclotron. The measured signal is amplified and connected to the input of a lock-in amplifier. The lock-in amplifier performs a synchronous detection of the signal at the cyclotron second harmonic frequency. The magnitude of the signal detected is calibrated against a Faraday cup and corresponds to the beam intensity. It has exceptional resolution, long term stability, and can measure the beam current leaving the cyclotron as low as 1 nA

  19. Test of detection unit for the cERL high-speed loss monitor

    International Nuclear Information System (INIS)

    In the High Energy Accelerator Research Organization (KEK), ERL (Energy Recovery Linac) which is a next-generation synchrotron orbital radiation light source is studied. Now, at KEK, various researches and technical development are performed by compact ERL (cERL) built for technical verification of ERL. Loss monitor development for protecting accelerator apparatus from damage by the beam collision of high energy as one of the interlocks for apparatus protection in it is performed. This loss monitor needs to stop a beam at high speed at the time of beam operation by high intensity (high current). This time, it tested by putting a sensor and a scintillator into the actual cERL accelerator interior of a room. As for these sensors and a scintillator, use by high-speed loss monitor is considered. Since implementability as a high-speed loss monitor was examined based on the test result, it is reported. (author)

  20. Data acquisition system for KOMAC beam monitoring using EPICS middleware

    Science.gov (United States)

    Song, Young-Gi

    2015-10-01

    The beam diagnostics instrument used to measure the beam properties is one of the important devices for the 100-MeV proton linear accelerator of the KOrea Multi-purpose Accelerator Complex (KOMAC). A data acquisition system (DAQ) is required to collect the output beam signals conditioned in the analog front-end circuitry of a beam loss monitor (BLM) and a beam position monitor (BPM). The electrical beam signal must be digitized, and the sampling has to be synchronized to a global timing system that produces a pulse signal for the pulsed beam operation. The digitized data must be accessible by the experimental physics and industrial control system (EPICS)-based control system, which manages all accelerator control. An input output controller (IOC), which runs Linux on a central process unit (CPU) module with a peripheral component interconnect (PCI) express-based Analog-to-digital converter (ADC) card, has been adopted to satisfy the requirements. An associated Linux driver and EPICS device support module have also been developed. The IOC meets the requirements, and the development and maintenance of software for the IOC is very efficient. In this paper, the details of the DAQ system for the BLM and the BPM with the introduction of the KOMAC beam-diagnostics devices, along with the performance, are described.

  1. Realization of a scanning ion beam monitor

    International Nuclear Information System (INIS)

    During this thesis, a scanning ion beam monitor has been developed in order to measure on-line fluence spatial distributions. This monitor is composed of an ionization chamber, Hall Effect sensors and a scintillator. The ionization chamber set between the beam exit and the experiment measures the ion rate. The beam spot is localized thanks to the Hall Effect sensors set near the beam sweeping magnets. The scintillator is used with a photomultiplier tube to calibrate the ionization chamber and with an imaging device to calibrate the Hall Effect sensors. This monitor was developed to control the beam lines of a radiobiology dedicated experimentation room at GANIL. These experiments are held in the context of the research in hadron-therapy. As a matter of fact, this new cancer treatment technique is based on ion irradiations and therefore demands accurate knowledge about the relation between the dose deposit in biological samples and the induced effects. To be effective, these studies require an on-line control of the fluence. The monitor has been tested with different beams at GANIL. Fluence can be measured with a relative precision of ±4% for a dose rate ranging between 1 mGy/s and 2 Gy/s. Once permanently set on the beam lines dedicated to radiobiology at GANIL, this monitor will enable users to control the fluence spatial distribution for each irradiation. The scintillator and the imaging device are also used to control the position, the spot shape and the energy of different beams such as those used for hadron-therapy. (author)

  2. Monitoring external beam radiotherapy using real-time beam visualization

    International Nuclear Information System (INIS)

    Purpose: To characterize the performance of a novel radiation therapy monitoring technique that utilizes a flexible scintillating film, common optical detectors, and image processing algorithms for real-time beam visualization (RT-BV). Methods: Scintillating films were formed by mixing Gd2O2S:Tb (GOS) with silicone and casting the mixture at room temperature. The films were placed in the path of therapeutic beams generated by medical linear accelerators (LINAC). The emitted light was subsequently captured using a CMOS digital camera. Image processing algorithms were used to extract the intensity, shape, and location of the radiation field at various beam energies, dose rates, and collimator locations. The measurement results were compared with known collimator settings to validate the performance of the imaging system. Results: The RT-BV system achieved a sufficient contrast-to-noise ratio to enable real-time monitoring of the LINAC beam at 20 fps with normal ambient lighting in the LINAC room. The RT-BV system successfully identified collimator movements with sub-millimeter resolution. Conclusions: The RT-BV system is capable of localizing radiation therapy beams with sub-millimeter precision and tracking beam movement at video-rate exposure

  3. Monitoring external beam radiotherapy using real-time beam visualization

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Cesare H. [Department of Mechanical Engineering and Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States); Naczynski, Dominik J.; Yu, Shu-Jung S.; Xing, Lei, E-mail: lei@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305 (United States)

    2015-01-15

    Purpose: To characterize the performance of a novel radiation therapy monitoring technique that utilizes a flexible scintillating film, common optical detectors, and image processing algorithms for real-time beam visualization (RT-BV). Methods: Scintillating films were formed by mixing Gd{sub 2}O{sub 2}S:Tb (GOS) with silicone and casting the mixture at room temperature. The films were placed in the path of therapeutic beams generated by medical linear accelerators (LINAC). The emitted light was subsequently captured using a CMOS digital camera. Image processing algorithms were used to extract the intensity, shape, and location of the radiation field at various beam energies, dose rates, and collimator locations. The measurement results were compared with known collimator settings to validate the performance of the imaging system. Results: The RT-BV system achieved a sufficient contrast-to-noise ratio to enable real-time monitoring of the LINAC beam at 20 fps with normal ambient lighting in the LINAC room. The RT-BV system successfully identified collimator movements with sub-millimeter resolution. Conclusions: The RT-BV system is capable of localizing radiation therapy beams with sub-millimeter precision and tracking beam movement at video-rate exposure.

  4. Development of Beam Conditions Monitor for the ATLAS experiment

    CERN Document Server

    Dolenc Kittelmann, Irena; Mikuž, M

    2008-01-01

    If there is a failure in an element of the accelerator the resulting beam losses could cause damage to the inner tracking devices of the experiments. This thesis presents the work performed during the development phase of a protection system for the ATLAS experiment at the LHC. The Beam Conditions Monitor (BCM) system is a stand-alone system designed to detect early signs of beam instabilities and trigger a beam abort in case of beam failures. It consists of two detector stations positioned at z=±1.84m from the interaction point. Each station comprises four BCM detector modules installed symmetrically around the beam pipe with sensors located at r=55 mm. This structure will allow distinguishing between anomalous events (beam gas and beam halo interactions, beam instabilities) and normal events due to proton-proton interaction by measuring the time-of-flight as well as the signal pulse amplitude from detector modules on the timescale of nanoseconds. Additionally, the BCM system aims to provide a coarse instan...

  5. BESSY Bragg-Fresnel multilayer beam monitors

    International Nuclear Information System (INIS)

    X-ray optical systems based on Bragg-Fresnel multilayer components imaging an electron beam in a storage ring with microm resolution are presented. Design concepts are compared to alternative methods, and the aberrations and limits of Bragg-Fresnel multilayer optics are discussed. Experimental results of imaging the BESSY 1 source with sub 10 microm resolution are presented and the development of a compact Bragg-Fresnel multilayer telescope as a BESSY 2 standard beam monitor is described

  6. The AGS Booster Beam Position Monitor system

    International Nuclear Information System (INIS)

    To accelerate both protons and heavy ions, the AGS Booster requires a broadband (multi-octave) beam position monitoring system with a dynamic range spanning several orders of magnitude (2 x 1010 to 1.5 x 1013 particles per pulse). System requirements include the ability to acquire single turn trajectory and average orbit information with ± 0.1 mm resolution. The design goal of ± 0.5 mm corrected accuracy requires that the detectors have repeatable linear performance after periodic bakeout at 300 degree C. The system design and capabilities of the Booster Beam Position Monitor will be described, and initial results presented. 7 refs., 5 figs

  7. Measuring emittance using beam position monitors

    International Nuclear Information System (INIS)

    The Los Alamos Advanced Free Electron Laser uses a high charge (greater than InC), low emittance (normalized rams emittance less than 5π mm mrad) photoinjector driven accelerator. The high brightness achieved is due, in large part, to the rapid acceleration of the electrons to relativistic velocities. As a result, the beam does not have time to thermalize its distribution and its universe profile is, in general, non-Gaussian. This, coupled with the very high brightness, makes it difficult to measure the transverse emittance. Techniques used must be able to withstand the rigors of very intense electron beams, and not be reliant on Gaussian assumptions. Beam position monitors are ideal for this. They are not susceptible to beam damage, and it has been shown previously that they can be used to measure the transverse emittance of a beam with a Gaussian profile. However, this Gaussian restriction is not necessary and, in fact, a transverse emittance measurement using beam position monitors is independent of the beam's distribution

  8. Comment on 'Proton beam monitor chamber calibration'.

    Science.gov (United States)

    Palmans, Hugo; Vatnitsky, Stanislav M

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that [Formula: see text]-values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961-71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication

  9. A beam radiation monitoring and protection system for AGS secondary beams

    International Nuclear Information System (INIS)

    A commercially available radiation monitor using a scintillation detector was modified for charged particle beam monitoring. The device controls access to secondary beams of the AGS and limits beam intensity

  10. Experimental determination of beam loss point in transport line-2 of Indus Accelerator Complex

    International Nuclear Information System (INIS)

    Radiation field in the Indus-1 SRS Experimental hall during 550 MeV electron beam injection into Transport Line-3 (TL-3)/Indus-2 was found to be higher than during 450 MeV beam injection to Transport line -2 (TL-2)/Indus-1. Experimental investigation was carried out to find out the location of beam loss. For the investigation, Ion chamber based detectors viz direct reading dosimeters (passive detectors) and beam loss monitors (active) were used. The beam loss point was observed near Sputter Ion Pump-5 (SIP-5) of TL-2, in Indus-1 area. The result was confirmed by induced activity profile measurements of the transport lines (TL-2/TL-3) during shut down. In order to reduce the radiation level in Indus-1 hall, two tenth value layers of lead shielding was put near TL2. Later on, correction in the beam optics by beam dynamics section reduced the beam losses at SIP-5 location, thereby reducing the radiation fields in Indus-1 hall substantially. The paper describes the measurement and the results in detail. (author)

  11. The CMS Beam Halo Monitor electronics

    Science.gov (United States)

    Tosi, N.; Dabrowski, A. E.; Fabbri, F.; Grassi, T.; Hughes, E.; Mans, J.; Montanari, A.; Orfanelli, S.; Rusack, R.; Torromeo, G.; Stickland, D. P.; Stifter, K.

    2016-02-01

    The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes (PMTs). The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few nanosecond resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and receives data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is read out via IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed in real time and published to CMS and the LHC, providing online feedback on the beam quality. A dedicated calibration monitoring system has been designed to generate short triggered pulses of light to monitor the efficiency of the system. The electronics has been in operation since the first LHC beams of Run II and has served as the first demonstration of the new QIE10, Microsemi Igloo2 FPGA and high-speed 5 Gbps link with LHC data.

  12. Calibration of a proton beam energy monitor.

    Science.gov (United States)

    Moyers, M F; Coutrakon, G B; Ghebremedhin, A; Shahnazi, K; Koss, P; Sanders, E

    2007-06-01

    Delivery of therapeutic proton beams requires an absolute energy accuracy of +/-0.64 to 0.27 MeV for patch fields and a relative energy accuracy of +/-0.10 to 0.25 MeV for tailoring the depth dose distribution using the energy stacking technique. Achromatic switchyard tunes, which lead to better stability of the beam incident onto the patient, unfortunately limit the ability of switchyard magnet tesla meters to verify the correct beam energy within the tolerances listed above. A new monitor to measure the proton energy before each pulse is transported through the switchyard has been installed into a proton synchrotron. The purpose of this monitor is to correct and/or inhibit beam delivery when the measured beam energy is outside of the tolerances for treatment. The monitor calculates the beam energy using data from two frequency and eight beam position monitors that measure the revolution frequency of the proton bunches and the effective offset of the orbit from the nominal radius of the synchrotron. The new energy monitor has been calibrated by measuring the range of the beam through water and comparing with published range-energy tables for various energies. A relationship between depth dose curves and range-energy tables was first determined using Monte Carlo simulations of particle transport and energy deposition. To reduce the uncertainties associated with typical scanning water phantoms, a new technique was devised in which the beam energy was scanned while fixed thickness water tanks were sandwiched between two fixed parallel plate ionization chambers. Using a multitude of tank sizes, several energies were tested to determine the nominal accelerator orbit radius. After calibration, the energy reported by the control system matched the energy derived by range measurements to better than 0.72 MeV for all nine energies tested between 40 and 255 MeV with an average difference of -0.33 MeV. A study of different combinations of revolution frequency and radial

  13. Laser Wire and Beam Position Monitor tests

    CERN Document Server

    Boogert, S T; Lyapin, A; Nevay, L; Snuverink, J

    2013-01-01

    This subtask involved two main activities; Firstly the development and subsequent usage of high resolution beam position monitors (BPM) for the International Linear Collider (ILC) and Compact Linear Collider projects (CLIC); and secondly the development of a laser-wire (LW) transverse beam size measurement systems. This report describes the technical progress achieved at a large-scale test ILC compatible BPM system installed at the Accelerator Test Facility 2 (ATF2). The ATF2 is an energy-scaled demonstration system for the final focus systems required to deliver the particle beams to collision at the ILC and CLIC. The ATF2 cavity beam position monitor system is one of the largest of its kind and rivals systems used at free electron lasers. The ATF2 cavity beam position system has achieved a position resolutionof 250 nm (with signal attuenation) and 27 nm (without attenuation). The BPM system has been used routinely for lattice diagnostics, beam based alignment and wakefield measurements. Extensive experience...

  14. LHC Collimators with Embedded Beam Position Monitors: a New Adbanced Mechanical Design

    CERN Document Server

    Dallocchio, A; Boccard, C; Carra, F; Gasior, M; Gentini, L; Timmins, M

    2011-01-01

    The LHC collimation system, ensuring both functions of beam cleaning and machine protection, is potentially submitted to high-energy beam impacts. Currently the collimators setup is performed by monitoring beam losses generated by the collimator jaws when approaching the particle beam. This procedure is applied to all LHC collimators (almost one hundred), taking several hours, and needs to be repeated if beam settings change significantly. Furthermore, during the beam-based alignment, the LHC tertiary collimators are potentially exposed to abnormal losses entailing possible damage to their tungsten jaws. To improve the efficiency of the machine operation and better control the particle beam a new advanced design embedding Beam Position Monitors (BPM) into the movable collimator jaws has been developed. This paper describes the mechanical design of various types of future collimators with embedded BPMs. Experimental measurements performed on a simplified functional prototype installed in the CERN SPS showed th...

  15. Beam loss scenarios for MuCool Test Area

    International Nuclear Information System (INIS)

    The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets, gas-filled RF cavities, and other apparatus being developed to cool intense, large-emittance muon beams. In this study the results of Monte Carlo modeling of several beam loss scenarios are presented. The MTA facility was designed to test targets and other muon cooling apparatus using the intense Fermilab Linac beam. The requested intensity of the proton beam for the MTA is essentially full Linac capability, or 1.6 x 1013 protons per pulse and an energy of 400 MeV. Two modes of operation will be supported in the MuCOOL beamline: one mode for emittance measurements (and beamline studies) and a second mode for MTA experiments. Maximum beam intensity for these two modes is: 9.6 x 1015 protons/hr - 600 beam pulses/hour of full Linac beam pulse intensity (1.6 x 1013 protons/pulse) to the emittance beam absorber and 9.6 x 1014 protons/hour - 60 beam pulses/hour of full Linac beam pulse intensity to experiments in the MTA experimental hall. This extremely high intensity implies careful investigation into and application of proper shielding materials and configuration in order to satisfy the following two requirements: (i) to reduce the instantaneous dose rate outside of the experimental enclosure to prescribed levels appropriate for the area considered; (ii) to ensure the civil construction of the hall is capable of additional shielding and, further, that the weight of the shielding is commensurate with the loading specifications of the enclosure, notably the ceiling. A number of scenarios for beam loss at different locations were studied in order to determine the maximum beam intensity which is in compliance with the existing shielding. The modeling was performed with the MARS15 code.

  16. Beam Loss Calibration Studies for High Energy Proton Accelerators

    CERN Document Server

    Stockner, M

    2007-01-01

    CERN's Large Hadron Collider (LHC) is a proton collider with injection energy of 450 GeV and collision energy of 7 TeV. Superconducting magnets keep the particles circulating in two counter rotating beams, which cross each other at the Interaction Points (IP). Those complex magnets have been designed to contain both beams in one yoke within a cryostat. An unprecedented amount of energy will be stored in the circulating beams and in the magnet system. The LHC outperforms other existing accelerators in its maximum beam energy by a factor of 7 and in its beam intensity by a factor of 23. Even a loss of a small fraction of the beam particles may cause the transition from the superconducting to the normal conducting state of the coil or cause physical damage to machine components. The unique combination of these extreme beam parameters and the highly advanced superconducting technology has the consequence that the LHC needs a more efficient beam cleaning and beam loss measurement system than previous accelerators....

  17. BESSY Bragg-Fresnel multilayer beam monitors

    International Nuclear Information System (INIS)

    X-ray optical systems based on Bragg-Fresnel multilayer components imaging an electron beam in a storage ring with μm resolution are presented. Design concepts are compared to alternative methods, and the aberrations and limits of Bragg-Fresnel multilayer optics are discussed. Experimental results of imaging the BESSY I source with sub-10-μm resolution are presented, and the development of a compact Bragg-Fresnel multilayer telescope as a BESSY II standard beam monitor is described. copyright 1996 American Institute of Physics

  18. Beam position monitoring electronics system for LEHIPA

    International Nuclear Information System (INIS)

    The primary function of beam position monitoring system (BPM) is to determine the position of the beam with respect to the centre of beam pipe. The present system is VME based and mainly consists of two VME boards one Analog and one Digital. The system has been developed for 352.21 MHz Low Energy High Intensity Proton Accelerator (LEHIPA). The electronic system processes the signals coming from the sensor which incorporates four button pick-ups placed orthogonally around the beam pipe. The fundamental component of the beam signal is extracted from the signals from the sensor and amplified with gain stabilized amplifiers on the analog board. Offset tone based technique has been used for the stabilization of the gain of the amplifiers against changes in temperature, power supply, etc. The filtered and amplified signals are given to the digital board for digitization and further processing. The signal processing consists of demodulation in I-Q domain followed by CORDIC which gives the signal information in the form of amplitude and phase. The stabilization of the gain is also carried out in the digital domain. The phase information can be utilized for energy gain measurements. The amplitudes give the position of the beam which is calculated online in FPGA using difference over sum method. The EPICS system has been chosen as the basic framework for command control. The hardware architecture is as per standard VME crate. (author)

  19. Beam halo monitoring at J-PARC 3-50 beam transport line using long air ionization chamber

    International Nuclear Information System (INIS)

    3 long-type Air Ionization Chambers (AICs) have been installed along 350BT which is the beam transport from the 3GeV Rapid Cycling Synchrotron (RCS) to the Main Ring synchrotron (MR) to monitor beam losses. 3-50BT collimators are used to remove beam halo components outside the emittance larger than 54[πmm · mrad] for horizontal and 60[πmm · mrad] for vertical plane, at present operations. By measuring the beam loss induced radiations from the 3-50BT collimators, the beam halo components have been monitoring on line. Details of the system, calibration results, and resolution of the system will be described in this paper. (author)

  20. Development of beam position monitor for test beam of BEPC II

    International Nuclear Information System (INIS)

    Three stripline beam position monitors and some feed-throughs were developed to measure the position of beam non-interceptively in test beam facility. After three stripline beam position monitors were produced, calibrations of the monitors were carried out on a workbench, which has high precision and is controlled by a computer. Then two monitor's were installed at the beam line and some experiments were carried out. Four 1 mm thickness stainless steel strips are main modules of the monitor, signals induced in these strips reflect the position of the beam bunch. Calibration coefficient, system characteristic impedance and port transmission coefficient of monitor are introduced in this paper. (authors)

  1. APCAL1: Beam Position Monitor Program

    International Nuclear Information System (INIS)

    APCAL1 is an applications program operational on the PEP MODCOMP IV computer for the purpose of converting beam position monitor (BPM) button voltage readings to x,y coordinates. Calibration information and the BPM readings are read from the MODCOMP IV data base. Corresponding x,y coordinates are written in the data base for use by other programs. APCAL1 is normally activated by another program but can be activated by a touch panel for checkout purposes

  2. Design Specifications for a Radiation Tolerant Beam Loss Measurement ASIC

    CERN Document Server

    Venturini, G G; Effinger, E; Zamantzas, C

    2009-01-01

    A novel radiation-hardened current digitizer ASIC is in planning stage, aimed at the acquisition of the current signals from the ionization chambers employed in the Beam Loss Monitoring system at CERN. The purpose is to match and exceed the performance of the existing discrete component design, currently in operation in the Large Hadron Collider (LHC). The specifications include: a dynamic range of nine decades, defaulting to the 1 pA-1mA range but adjustable by the user, ability to withstand a total integrated dose of 10 kGy at least in 20 years of operation and user selectable integrating windows, as low as 500 ns. Moreover, the integrated circuit should be able to digitize currents of both polarity with a minimum number of external components and without needing any configuration. The target technology is the IBM 130nm CMOS process. The specifications, the architecture choices and the reasons on which they are based upon are discussed in this paper.

  3. Study of Acquisition Electronics with a High Dynamic Range for a Beam Loss Measurement System

    CERN Document Server

    Venturini, G; Dehning, B; Effinger, E

    2010-01-01

    The particles accelerated in CERN accelerator chain reach high energies, topped by the particle energy at collision in the LHC, 7 GeV. During the operation, an amount of particles is inevitably lost from the beam. Depending on the extent of the losses, physical damage to machine components may be caused and the shower of secondary emission particles deposits energy in the surrounding equipment constituting the accelerator. The hadronic cascade also activates their materials, representing a hazard to the workers at CERN. In the LHC, the superconducting magnets that constitute the synchrotron lattice are kept at an operating temperature of 1:9K through a cryogenic facility employing superliquid helium, the increase in their temperature potentially initiates a quench. In the SPS, the damage due to a lost beam is also visible. The Beam Loss Monitoring (BLM) system has been developed to reliably protect the machines composing CERN’s accelerator chain and additionally provide information about the beam status: th...

  4. SPS transverse beam scraping and LHC injection losses

    CERN Document Server

    Drosdal, L; Bartmann, W; Bracco, C; Cornelis, K; Goddard, B; Meddahi, M; Veyrunes, E

    2012-01-01

    Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.

  5. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    CMS Collaboration

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. In this talk we will describ...

  6. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    Stifter, Kelly Marie

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to supress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. In this talk we will descri...

  7. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    Stifter, Kelly

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. Here, I present the detector...

  8. Monitoring the beam position in the SLC interaction region

    International Nuclear Information System (INIS)

    The Stanford Linear Collider requires special Beam Position Monitors near the Interaction Point (IP) to bring the two beams (e+ and e-) into collision. These beams pass through two monitors on each side of the IP with a short time separation (about 20 and 50 ns). The mechanics of the monitors as well as the electronics will be described. In order to bring beams of several microns diameter into collision at the IP, these monitors measure beam deflection induced by the presence of the opposite beam

  9. Beam loss and radiation effects in the SSC lattice elements

    International Nuclear Information System (INIS)

    The Superconducting Super Collider (SSC) is designed to be an advanced machine with relatively low beam loss-induced radiation levels. However, a fraction of the beam lost in the lattice due to pp-collisions at the interaction points, beam-gas scattering, bearn-halo scraping, various instabilities and errors will result in the irradiation of conventional and superconducting components of the accelerator and experimental apparatus. The level of the beam loss and its distribution along the machine structure has impact on all of the three crucial radiation effects at the SSC: quenching of the superconducting magnets, survivability of the accelerator and detectors components in the near-beam regions, and influence to the environment. This paper, based on the full-scale Monte Carlo simulation, will explore all major sources of beam loss in the Collider and measures to reduce the irradiation of the accelerator components. Basic parameters of the Super Collider accepted throughout this report are as follows: Proton energy E0 = 20 TeV, injection energy is 2 TeV, number of protons circulating in each of the collider rings is N = 1.3 x 1014, circumference is 87.12 km, the transverse normalized emittance var-epsilon N(σ) = 1 π mm-mrad, for the regular lattice (β = 305 m) the beam R.M.S. sizes are σ = 0.12 mm at 20 TEV and σ = 0.38 mm at the injection energy. The dipole length is 15.815 m with the effective field length of 15.165 m. The magnetic field map for B0 = 6.5999 T has been calculated with the POISSON program by Greg Snitchler. The turn angle of each dipole is α = 1.50027 mrad. The dipole aperture is 50 mm. The two beam pipe diameters are studied 33 and 40 mm. The operating temperature is T0 = 4.35 K

  10. Investigation of the use of Silicon, Diamond and liquid Helium detectors for Beam Loss Measurements at 2K

    CERN Document Server

    Kurfuerst, C; Eisel, T; Sapinski, M; Eremin, V; Fabjan, C

    2012-01-01

    At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring (BLM) system is very sensitive to the debris from the collisions. For future beams with higher energy and higher luminosity this will lead to a situation in which the BLM system can no longer distinguish between these interaction products and quench-provoking beam losses from the primary proton beams. The solution investigated is to locate the detectors as close as possible to the superconducting coil, i.e. the element to be protected. This means putting detectors inside the cold mass of the superconducting magnets at 1.9 K. As possible candidates for such loss monitors, diamond, silicon and a liquid helium chamber have been tested in a proton beam at liquid helium temperatures. The initial promising results from these tests will be presented and discussed in this contribution.

  11. Tracking Simulation for Beam Loss Studies with Application to FCC

    CERN Document Server

    Boscolo, M

    2015-01-01

    We present first results on FCC-ee beam losses using a tracking simulation tool originally developed and successfully applied to Flav or Factories designs. After a brief description of the tool, we discuss first results obtained for FCC-ee at top energy, both for the Touschek effect and radiative Bhabha scattering.

  12. beam loss scenarios for MuCool Test Area

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, Igor; Johnstone, Carol; /Fermilab

    2010-08-01

    The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets, gas-filled RF cavities, and other apparatus being developed to cool intense, large-emittance muon beams. In this study the results of Monte Carlo modeling of several beam loss scenarios are presented. The MTA facility was designed to test targets and other muon cooling apparatus using the intense Fermilab Linac beam. The requested intensity of the proton beam for the MTA is essentially full Linac capability, or 1.6 x 10{sup 13} protons per pulse and an energy of 400 MeV. Two modes of operation will be supported in the MuCOOL beamline: one mode for emittance measurements (and beamline studies) and a second mode for MTA experiments. Maximum beam intensity for these two modes is: 9.6 x 10{sup 15} protons/hr - 600 beam pulses/hour of full Linac beam pulse intensity (1.6 x 10{sup 13} protons/pulse) to the emittance beam absorber and 9.6 x 10{sup 14} protons/hour - 60 beam pulses/hour of full Linac beam pulse intensity to experiments in the MTA experimental hall. This extremely high intensity implies careful investigation into and application of proper shielding materials and configuration in order to satisfy the following two requirements: (i) to reduce the instantaneous dose rate outside of the experimental enclosure to prescribed levels appropriate for the area considered; (ii) to ensure the civil construction of the hall is capable of additional shielding and, further, that the weight of the shielding is commensurate with the loading specifications of the enclosure, notably the ceiling. A number of scenarios for beam loss at different locations were studied in order to determine the maximum beam intensity which is in compliance with the existing shielding. The modeling was performed with the MARS15 code.

  13. Simulation and Measurements of Beam Losses on LHC Collimators During Beam Abort Failures

    CERN Document Server

    Lari, L; Bruce, R; Goddard, B; Redaelli, S; Salvachua, B; Valentino, G; Faus-Golfe, A

    2013-01-01

    One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

  14. Signal Processing for Beam Position Monitors

    CERN Document Server

    Vismara, Giuseppe

    2000-01-01

    At the first sight the problem to determine the beam position from the ratio of the induced charges of the opposite electrodes of a beam monitor seems trivial, but up to now no unique solution has been found that fits the various demands of all particle accelerators. The purpose of this paper is to help "instrumentalists" to choose the best processing system for their particular application, depending on the machine size, the input dynamic range, the required resolution and the acquisition speed. After a general introduction and an analysis of the electrical signals to be treated (frequency and time domain), the definition of the electronic specifications will be reviewed. The tutorial will present the different families in which the processing systems can be grouped. A general description of the operating principles with relative advantages and disadvantages for the most employed processing systems is presented. Special emphasis will be put on recent technological developments based on telecommunication circ...

  15. H- Beam Stripping Loss at Background Partial Pressure of Ar

    Institute of Scientific and Technical Information of China (English)

    Hu Chundong; Wang Shaohu; Hu Liqun

    2005-01-01

    It has been observed that H- current could be improved by adding Ar to H2 plasma.But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length of a beam pulse. Since H- stripping loss depends on the tank pressure and gas species, part of the H- beam can be converted to H0 and then H0 can be converted into H+ with background H2 and Ar gas thickness. Therefore, the H- beam current,measured by a Faraday cup, situated at a distance L from GG (ground grid), will decrease because it will be converted into a H+ current. This gives a ratio of the Faraday cup net current to the H- beam current before stripping at background partial pressure of Ar.

  16. New detector for neutron beam monitor

    International Nuclear Information System (INIS)

    In order to obtain high precision in neutron cross-section measurements, an essential aspect is the accurate knowledge of the energy distribution of the neutron flux during the measurements. The detector dedicated to this measurement should measure the neutron flux impinging on the sample placed in the beam; therefore it should be placed upstream of the sample position and of the different detectors in the measurement area. As a consequence of that, such a flux detector should ideally have an in-beam mass as small as possible in order to minimize the perturbation on the neutron beam and to minimize the production of background by the device itself. According to these considerations a new neutron detector equipped with a small-mass device based on Micromegas micro-bulk technology has been designed for monitoring the CERN nTOF neutron beam. In order to cover the full range of the neutron energy from thermal to several MeV, two neutron/charged particle converters (235U and 10B) have been used. The 235U(n,f) is suited above a few 100 eV. Below that energy the resonance structure of 235U(n,f) does not allow a precise determination of the neutron flux without taking into account detailed and complicated corrections. To overcome this issue the 10B(n,α) reaction is simultaneously used. After a description of the innovative detector concept, we present the result obtained at the GELINA neutron beam facility of JRC-IRMM Geel, and the preliminary results from the commissioning of the new target of the CERN nTOF facility. (author)

  17. An interactive beam position monitor system simulator

    International Nuclear Information System (INIS)

    A system simulator has been implemented to aid the development of the RHIC position monitor system. Based on the LabVIEW software package by National Instruments, this simulator allows engineers and technicians to interactively explore the parameter space of a system during the design phase. Adjustable parameters are divided into three categories: beam, pickup, and electronics. The simulator uses these parameters in simple formulas to produce results in both time-domain and frequencydomain. During the prototyping phase, these simulated results can be compared to test data acquired with the same software package. The RHIC position monitor system is presented as an example, but the software is applicable to several other systems as well

  18. Performance Studies of the Vibration Wire Monitor on the Test Stand with Low Energy Electron Beam

    Science.gov (United States)

    Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu

    In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic

  19. Monitoring relativistic heavy ion beams at the Bevalac

    International Nuclear Information System (INIS)

    Beam fluence in high intensity proton and electron accelerators is usually measured with Secondary Emission Monitors (SEM) calibrated by an activation method. These were no such activation measurements available for relativistic heavy ion beams. Secondary electron production and energy loss of a charged particle in passing through material are a result of Coulomb interaction between the projectile field and electrons in the material. Therefore range measurements and secondary emission yield should follow the same functional relationship of velocity and charge as given by the Bethe-Bloch equation. A substantial amount of data on range in water for various ions has been collected at the Bevalac Biomedical facility. Using the same calculations that convert measured proton ranges to ion ranges and comparing the calculated values to measured values, provides an indirect way to verify the validity of the SEM calibration. The results of these measurements are discussed in this paper

  20. Beam energy loss to parasitic modes in SPEAR II

    International Nuclear Information System (INIS)

    The energy loss due to the excitation of parasitic modes in the SPEAR II rf cavities and vacuum chamber components has been measured by observing the shift in synchronous phase angle as a function of circulating beam current and accelerating cavity voltage. The resulting parasitic mode loss resistance is 5 Mω at a bunch length of 6.5 cm. The loss resistance varies with bunch length σ/sub z/ approximately as exp(/minus/0.3 σ/sub z/). If the measured result is compared with reasonable theoretical predictions, we infer that the major portion of the parasitic loss takes place in ring vacuum components rather than in the rf cavities. 7 refs., 5 figs., 2 tabs

  1. The CMS Beam Halo Monitor Electronics

    CERN Document Server

    Tosi, Nicolo

    2015-01-01

    The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes. The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few ns resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and receives data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is readout by IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed in real time and published to CMS and the LHC, provid...

  2. Performance of the CMS Beam Halo Monitor

    CERN Document Server

    CMS Collaboration

    2015-01-01

    The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of radiation hard synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes for a direction sensitive measurement. The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few ns resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and received data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is readout by IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed i...

  3. Statistical Treatment of Beam Position Monitor Data

    CERN Document Server

    Reiter, Andreas; Chorniy, Oleksandr

    2016-01-01

    We review beam position monitors adopting the perspective of an analogue-to- digital converter in a sampling data acquisition system. From a statistical treatment of independent data samples we derive basic formulae of position uncertainty for beam position monitors. Uncertainty estimates only rely on a few simple model parameters and have been calculated for two "practical" signal shapes, a square pulse and a triangular pulse. The analysis has been carried out for three approaches: the established signal integration and root-sum-square ap- proaches, and a least-square fit for the models of direct proportion and straight-line. The latter approach has not been reported in the literature so far. The straight-line fit provides the most robust estimator since it does not require baseline restoration, it is immune to signal offsets, and its standard deviation is smallest. Consequently, of the analysed estimators it promises the highest fidelity of results. The fit approach represents a simple, natural way to analy...

  4. Design of CMS Beam Halo Monitor system

    CERN Document Server

    AUTHOR|(CDS)2078842

    2015-01-01

    A fast and directional monitoring system for the CMS experiment is designed to provide an online, bunch-by-bunch measurement of beam background induced by beam halo interactions, separately for each beam. The background detection is based on Cherenkov radiation produced in synthetic fused silica read out by a fast, UV sensitive photomultiplier tube. Twenty detector units per end will be azimuthally distributed around the rotating shielding of CMS, covering ~408 cm2 at 20.6m from the interaction point, at a radius of ~180 cm. The directional and fast response of the system allows the discrimination of the background particles from the dominant flux in the cavern induced by pp collision debris, produced within the 25 ns bunch spacing. A robust multi-layered shielding will enclose each detector unit to protect the photomultiplier tube from the magnetic field and to eliminate the occupancy from low energy particles. The design of the front-end units is validated by experimental results. An overview of the new sy...

  5. Beam-beam deflection and beamstrahlung monitor response for tilted elliptic beams

    International Nuclear Information System (INIS)

    At the interaction point of the SLC two oppositely running bunches with energies of 46 GeV and transverse extensions of a few microns are brought into collision. The strong electron and magnetic fields produced by one bunch lead to a deflection of the other bunch and to the emission of synchrotron radiation of critical energies of a few 10 MeV. This radiation, coined beamstrahlung, is detected in a Cerenkov monitor. In this paper a simulation code for the beam-beam interaction of two tilted elliptic beams is presented. A closed expression for the deflection angles is presented and the number of generated Cerenkov photons is calculated

  6. Fermilab booster operational status: Beam loss and collimation

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Webber

    2002-06-11

    Beam loss reduction and control challenges confronting the Fermilab Booster are presented in the context of the current operational status. In Summer 2002 the programmatic demand for 8 GeV protons will increase to 5E20/year. This is an order of magnitude above recent high rates and nearly as many protons as the machine has produced in its entire 30-year lifetime. Catastrophic radiation damage to accelerator components must be avoided, maintenance in an elevated residual radiation environment must be addressed, and operation within a tight safety envelope must be conducted to limit prompt radiation in the buildings and grounds around the Booster. Diagnostic and performance tracking improvements, enhanced orbit control, and a beam loss collimation/localization system are essential elements in the approach to achieving the expected level of performance and are described here.

  7. Development of KOMAC Beam Monitoring System Using EPICS

    International Nuclear Information System (INIS)

    The beam loss signals must be digitized and the sampling has to be synchronized to a reference signal which is an external trigger for beam operation. The digitized data must be accessible by the Experimental Physics and Industrial Control System (EPICS)-based control system, which manages the whole accelerator control. In order to satisfy the requirement, an Input /Output Controller (IOC), which runs Linux on a CPU module with PCI express based Analog to Digital Converter (ADC) modules, has been adopted. An associated linux driver and EPICS device support module also have been developed. The IOC meets the requirements and the development and maintenance of the software for the IOC is considerably efficient. The data acquisition system running EPICS will be used in increasing phase of KOrea Multi-purpose Accelerator Complex (KOMAC) beam power. The beam monitoring system integrates BLM and BPM signals into control system and offers real-time data to operators. The IOC, which is implemented with Linux and PCI driver, has supported data acquisition as a very flexible solution

  8. Development of KOMAC Beam Monitoring System Using EPICS

    Energy Technology Data Exchange (ETDEWEB)

    Song, Young-Gi; Yun, Sang-Pil; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The beam loss signals must be digitized and the sampling has to be synchronized to a reference signal which is an external trigger for beam operation. The digitized data must be accessible by the Experimental Physics and Industrial Control System (EPICS)-based control system, which manages the whole accelerator control. In order to satisfy the requirement, an Input /Output Controller (IOC), which runs Linux on a CPU module with PCI express based Analog to Digital Converter (ADC) modules, has been adopted. An associated linux driver and EPICS device support module also have been developed. The IOC meets the requirements and the development and maintenance of the software for the IOC is considerably efficient. The data acquisition system running EPICS will be used in increasing phase of KOrea Multi-purpose Accelerator Complex (KOMAC) beam power. The beam monitoring system integrates BLM and BPM signals into control system and offers real-time data to operators. The IOC, which is implemented with Linux and PCI driver, has supported data acquisition as a very flexible solution.

  9. Design of a Nanometer Beam Size Monitor for ATF2

    CERN Document Server

    Suehara, Taikan; Yamanaka, Takashi; Yoda, Hakutaro; Nakamura, Tomoya; Kamiya, Yoshio; Honda, Yosuke; Kume, Tatsuya; Tauchi, Toshiaki; Sanuki, Tomoyuki; Komamiya, Sachio

    2008-01-01

    We developed an electron beam size monitor for extremely small beam sizes. It uses a laser interference fringe for a scattering target with the electron beam. Our target performance is < 2 nm systematic error for 37 nm beam size and < 10% statistical error in a measurement using 90 electron bunches for 25 - 6000 nm beam size. A precise laser interference fringe control system using an active feedback function is incorporated to the monitor to achieve the target performance. We describe an overall design, implementations, and performance estimations of the monitor.

  10. Proposal for the LHC beam dump upstream diagnostics monitor.

    CERN Document Server

    Variola, A

    2000-01-01

    A diagnostic system is proposed to monitor the beam dilution profile at the entrance of the LHC main beam dump. The monitor exploits two different types of optical photon emission: (a) luminescence on an alumina screen in the case of normal or partial beam dilution; (b) optical transition radiation by a carbon plate in case of a total dilution failure. Based on the analyses, this system is able to resolve with sufficient accuracy the beam location and to resist the beam load under any operating condition. An effective optical set-up of the beam imaging system is also proposed, providing a preliminary design of the diagnostic station.

  11. Beam Shape and Halo Monitor Study

    CERN Document Server

    Lallement, J B; Hori, M; CERN. Geneva. AB Department

    2006-01-01

    The Beam Shape and Halo Monitor, designed by Masaki Hori, is the main diagnostic tool for the 3 MeV test stand scheduled in 2008. This detector will be able to measure the transverse halo generated in the RFQ and the Chopper-line and to detect and measure the longitudinal halo composed of the incompletely chopped bunches. Its principle of functioning is the following: H- ions hit a carbon foil and generate secondary electrons with the same spatial distribution than the incoming beam and a current depending on an emission coefficient given by the carbon foil. These electrons are accelerated towards a phosphor screen by an electric field applied between accelerating grids. Once the electrons reach the phosphor screen, they generate light which is transmitted to a CCD camera via optic fibers [1]. It is expected to give a time resolution of 1-2ns and a spatial resolution of 1mm. The first test of the BSHM done with a Laser has shown a spatial resolution bigger than 1cm and the time resolution bigger than 2ns[2]. ...

  12. NSLS-II RF BEAM POSITION MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, K.; Della Penna, A. J.; DeLong, J.; Kosciuk, B.; Mead, J.; Pinayev, I.; Singh, O.; Tian, Y.; Ha, K.; Portmann, G.; Sebek J.

    2011-03-28

    An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPM's in +-0.1 C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS. The development of a sub-micron BPM for the NSLS-II has successfully demonstrated performance and stability. Pilot Tone calibration combiner and RF synthesizer has been implemented and algorithm development is underway. The program is currently on schedule to start production development of 60 Injection BPM's starting in the Fall of 2011. The production of {approx}250 Storage Ring BPM's will overlap the Injection schedule.

  13. Monitoring packet loss impact in IPTV and 3DTV receivers

    OpenAIRE

    Gutierrez Sanchez, Jesus; Pérez García, Pablo; Jaureguizar Núñez, Fernando; Cabrera Quesada, Julian; García Santos, Narciso

    2012-01-01

    Considering a scalable video quality monitoring architecture to detect transmission errors at households, we propose a technique to detect packet losses in IPTV and Side-by-Side 3DTV and evaluate their impact on the perceived quality.

  14. A secondary emission type beam profile monitor with carbon graphite ribbons

    International Nuclear Information System (INIS)

    We developed a secondary emission type beam profile monitor with carbon graphite ribbons as a beam target. The carbon graphite is excellent in endurance against heat load, and that they are thin as 1.6-3.0 micron and low z (=6) are advantage for reducing beam loss. Furthermore, since ribbons emits larger amount of electrons than ordinal metal wires because of larger surface, the monitor has higher sensitivity. The monitors were installed in the end of 3-50 BT and injection point of MR in J-PARC, in order to measure injection beam profiles by single passing. Normal size target has 32ch ribbons with 2 or 3 mm in width and their length is 200 mm each. In this paper, basic characteristics of the carbon graphite target and results of beam measurement are reported. (author)

  15. A beam profile monitor using the ionization of residual gas in the beam pipe

    International Nuclear Information System (INIS)

    A beam profile monitor for high energy beams, which has no intercepting parts in the beam pipe, is described. It makes use of the ionization of the residual gas, which is still present in the vacuum chamber of the beam guiding system. The detection of the ionization products is performed with microchannel plates. (orig.)

  16. Measurement of Beam Loss at the Australian Synchrotron

    CERN Document Server

    Holzer, EB; Kastriotou, M; Boland, MJ; Jackson, PD; Rasool, RP; Schmidt, J; Welsch, CP

    2014-01-01

    The unprecedented requirements that new machines are setting on their diagnostic systems is leading to the development of new generation of devices with large dynamic range, sensitivity and time resolution. Beam loss detection is particularly challenging due to the large extension of new facilities that need to be covered with localized detector. Candidates to mitigate this problem consist of systems in which the sensitive part of the radiation detectors can be extended over long distance of beam lines. In this document we study the feasibility of a BLM system based on optical fiber as an active detector for an electron storage ring. The Australian Synchrotron (AS) comprises a 216m ring that stores electrons up to 3GeV. The Accelerator has recently claimed the world record ultra low transverse emittance (below pm rad) and its surroundings are rich in synchrotron radiation. Therefore, the AS provides beam conditions very similar to those expected in the CLIC/ILC damping rings. A qualitative benchmark of beam l...

  17. 2014 CERN Accelerator Schools: Beam Loss and Accelerator Protection

    CERN Multimedia

    2014-01-01

    The US-CERN-JAPAN-RUSSIA Joint International Accelerator School is organising a course on Beam Loss and Accelerator Protection to be held in Newport Beach, California, USA from 5-14 November, 2014.    This school is intended for physicists and engineers who are or may be engaged in the design, construction, and/or operation of accelerators with high power photon or particle beams and/or accelerator sub-systems with large stored energy. Application deadlines are 15 August and 4 September. Further information on this Joint School can be found at: http://cas.web.cern.ch/cas/JAS/Newport%20Beach%202014/NPBadvert.html http://indico.cern.ch/event/287647/ http://uspas.fnal.gov/programs/JAS/JAS14.shtml

  18. Duration of memory loss due to electron beam exposure. Final report Jan-May 1983

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T.G.; Tilton, B.M.

    1983-08-01

    Electron beam exposure has been shown to produce retrograde amnesia (RA). The objective of this study was to determine the duration of memory loss upon electron beam exposure. It is important to know if exposure produces a memory loss of the events which occurred in the preceding 1 sec or memory loss of the preceding minute's events. The task was a single-trial avoidance paradigm. The animal was placed in a small aversive chamber. After a 90-sec adaptation period, a door opened that provided access to a large, dark, preferred chamber. The time required for the animal to enter the preferred chamber was the measure of interest (T). Once inside the preferred chamber, a 1-sec footshock was delivered. Following the footshock by some preset delay (delta T), the animal was exposed to a 10-microsec, 10-rad electron beam (or X-ray). A second trial on the task was run 2 hr postexposure. The second trial consisted of placing the animal in the aversive chamber and monitoring the time (T') required to enter the preferred chamber. If the electron beam exposure interfered with the animal's ability to recall the shock, T' would be greatly reduced as compared with the sham controls. The exposure delay times used were delta T = 1, 3, 5, and 10 sec.

  19. Beam-profile monitor using a sodium-vapour

    CERN Multimedia

    1972-01-01

    Beam-profile monitor using a sodium-vapour curtain at 45 degrees to the ISR beam in Ring I (sodium generator is in white cylinder just left of centre). Electrons produced by ionization of the sodium vapour give an image of the beam on a fluorescent screen that is observed by a TV camera (at upper right).

  20. New fast beam profile monitor for electron-positron colliders.

    Science.gov (United States)

    Bogomyagkov, A V; Gurko, V F; Zhuravlev, A N; Zubarev, P V; Kiselev, V A; Meshkov, O I; Muchnoi, N Yu; Selivanov, A N; Smaluk, V V; Khilchenko, A D

    2007-04-01

    A new fast beam profile monitor has been developed at the Budker Institute of Nuclear Physics. This monitor is based on the Hamamatsu multianode photomultiplier with 16 anode strips and provides turn-by-turn measurement of the transverse beam profile. The device is equipped with an internal memory, which has enough capacity to store 131,072 samples of the beam profile. The dynamic range of the beam profile monitor allows us to study turn-by-turn beam dynamics within the bunch charge range from 1 pC up to 10 nC. Using this instrument, we have investigated at the VEPP-4M electron-positron collider a number of beam dynamics effects which cannot be observed by other beam diagnostics tools. PMID:17477653

  1. High resolution beam profile monitors in the SLC

    International Nuclear Information System (INIS)

    In the SLC linac, low emittance beams with typical transverse dimensions less than 0.2 mm must be accelerated without effective emittance growth. In order to monitor this we have installed a high resolution beam profile monitor system which consists of an aluminum target covered with a fine-grained phosphor, a magnifying optical system, a television camera and video signal recording electronics. The image formed when the beam strikes the phosphor screen is viewed on a CRT monitor at the console and selected horizontal and vertical slices of the beam spot intensity are recorded. A 20 MHz transient waveform recorder is used to sample and digitize the raw video signal along the selected slice. The beam width is determined by fitting the background subtracted data to a Gaussian. Beam spots less than 6 x 3 mm can be viewed. Beam spot sizes sigma/sub x,y/ < 80 μm have been measured. 9 refs., 4 figs

  2. Development of a Laser Wire Beam Profile Monitor, 1

    CERN Document Server

    Sakamura, Y; Matsuo, H; Sakai, H; Sasao, N; Higashi, Y; Korhonen, T T; Taniguchi, T; Urakawa, J; Sakamura, Yutaka; Hemmi, Yasuo; Matsuo, Hiroaki; Sakai, Hiroshi; Sasao, Noboru; Higashi, Yasuo; Korhonen, Timo; Taniguchi, Takashi; Urakawa, Junji

    1999-01-01

    A conceptual design work and a basic experimental study of a new beam profile monitor have been performed. The monitor will be used to measure emittance of an electron beam in the ATF damping ring at KEK, in which the transverse beam size of about 10 micron is expected. It utilizes a CW laser and an optical cavity, instead of a material wire, to minimize interference with an electron beam. A laser beam with a very thin waist is realized by employing the cavity of nearly concentric mirror configuration while the intensity is amplified by adjusting the cavity length to a Fabry-Perot resonance condition. We built a test cavity to establish a method to measure important parameters such as a laser beam waist and a power enhancement factor. Three independent methods were examined for the measurement of the beam waist. It was found that the cavity realized the beam waist of 20 micron with the power enhancement factor of 50.

  3. An LHCb general-purpose acquisition board for beam and background monitoring at the LHC

    International Nuclear Information System (INIS)

    In this paper we will present an LHCb custom-made acquisition board which was developed for a continuous beam and background monitoring during LHC operations at CERN. The paper describes both the conceptual design and its performance, and concludes with results from the first period of beam operations at the LHC. The main purpose of the acquisition board is to process signals from a pair of beam pickups to continuously monitor the intensity of each bunch, and to monitor the phase of the arrival time of each proton bunch with respect to the LHC bunch clock. The extreme versatility of the board also allowed the LHCb experiment to build a high-speed and high-sensitivity readout system for a fast background monitor based on a pair of plastic scintillators. The board has demonstrated very good performance and proved to be conceptually valid during the first months of operations at the LHC. Connected to the beam pickups, it provides the LHCb experiment with a real-time measurement of the total intensity of each beam and of the arrival time of each beam at the LHCb Interaction Point. It also monitors the LHC filling scheme and the beam current per bunch at a continuous rate of 40 MHz, and assures a proper global timing of LHCb. The continuous readout of the scintillators at bunch clock speed provides the LHCb experiment with high-resolution information about the beam halo and fast losses during both injection and circulating beam. It has also provided valuable information to the LHC during machine commissioning with beam. Recent results also shows that it could contribute as a luminosity monitor independent from the LHCb experiment readout system. Beam, background and luminosity measurements are continuously fed back to the LHC in the data exchange framework between the experiments and the LHC machine aimed at improving efficiently the experimental conditions real-time.

  4. High current precision long pulse electron beam position monitor

    CERN Document Server

    Nelson, S D; Fessenden, T J; Holmes, C

    2000-01-01

    Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

  5. The SRI Beam Size Monitor Developed at NSRRC

    CERN Document Server

    Tseng, Tse-Chuan; Ho, H C; Jen Wang, Duan; Kuan, Chien-Kuang; Lin, Chia-Jui; Perng, Shen-Yaw; Wang, Jeremy

    2005-01-01

    A beam size monitor based on the synchrotron radiation interferometer (SRI) was installed in the NSRRC TLS. This monitor consists of a simple diagnostic beamline with a water-cooled beryllium mirror inside and a detecting optical system for both vertical and horizontal beam size measurement. The beam sizes measured are 48 micron and 160 micron respectively and are more close to the theoretical values than the synchrotron image monitor. Comparing with other monitors, at least 1 micron beam size variation is detectable. To minimize the thermal effect, the mirror is located far away from the source point and closed to the detecting optical system. The thermal distortion of the mirror is quite small measured by a portable long trace profiler (LTP) and agrees with the simulating analysis. The detailed monitor system design and testing results are presented in this paper.

  6. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    International Nuclear Information System (INIS)

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  7. Automatic control and monitoring of the MIT fission converter beam

    International Nuclear Information System (INIS)

    An automated control and monitoring system for the new MIT high intensity epithermal neutron irradiation facility has been designed and constructed. The neutron beam is monitored with fission counters located at the periphery of the beam near the patient position. Control of the beam is accomplished with redundant Programmable Logic Controllers (PLCs). These industrial controllers open and close the three shutters of the Fission Converter Beam. The control system uses a series of robust components to assure that the prescribed fluence is delivered. This paper discusses the design and implementation of this system. (author)

  8. Beam Position Monitor Electronics Upgrade for Fermilab Switchyard

    CERN Document Server

    Stabile, P; Fitzgerald, J A; Liu, N; Morris, D K; Prieto, P S; Seraphin, J P

    2015-01-01

    The beam position monitor (BPM) system for Fermilab Switchyard (SY) provides the position, intensity and integrated intensity of the 53.10348 MHz RF bunched resonant extracted beam from the Main Injector over 4 seconds of spill. The total beam intensity varies from 1x10^11 to 1x10^13 protons. The spill is measured by stripline beam postion monitors and resonant circuit. The BPMs have an external resonant circuit tuned to 53.10348 MHz. The corresponding voltage signal out of the BPM has been estimated to be between -110 dBm and -80 dBm.

  9. Loss of accuracy using smeared properties in composite beam modeling

    Science.gov (United States)

    Liu, Ning

    Advanced composite materials have broad, proven applications in many engineering systems ranging from sports equipment sectors to components on the space shuttle because of their lightweight characteristics and significantly high stiffness. Together with this merit of composite materials is the challenge of improving computational simulation process for composites analysis. Composite structures, particularly composite laminates, usually consist of many layers with different lay-up angles. The anisotropic and heterogeneous features render 3D finite element analysis (FEA) computationally expensive in terms of the computational time and the computing power. At the constituent level, composite materials are heterogeneous. But quite often one homogenizes each layer of composites, i.e. lamina, and uses the homogenized material properties as averaged (smeared) values of those constituent materials for analysis. This is an approach extensively used in design and analysis of composite laminates. Furthermore, many industries tempted to use smeared properties at the laminate level to further reduce the model of composite structures. At this scale, smeared properties are averaged material properties that are weighted by the layer thickness. Although this approach has the advantage of saving computational time and cost of modeling significantly, the prediction of the structural responses may not be accurate, particularly the pointwise stress distribution. Therefore, it is important to quantify the loss of accuracy when one uses smeared properties. In this paper, several different benchmark problems are carefully investigated in order to exemplify the effect of the smeared properties on the global behavior and pointwise stress distribution of the composite beam. In the classical beam theory, both Newtonian method and variational method include several ad hoc assumptions to construct the model, however, these assumptions are avoided if one uses variational asymptotic method. VABS

  10. Beam position monitor data acquisition for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

    1993-01-01

    This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems.

  11. Beam position monitor data acquisition for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

    1993-06-01

    This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems.

  12. Beam position monitor data acquisition for the Advanced Photon Source

    International Nuclear Information System (INIS)

    This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems

  13. Production of Inorganic Thin Scintillating Films for Ion Beam Monitoring Devices

    CERN Document Server

    Re, Maurizio; Cosentino, Luigi; Cuttone, Giacomo; Finocchiaro, Paolo; Hermanne, Alex; Lojacono, Pietro A; Ma, YingJun; Thienpont, Hugo; Van Erps, Jurgen; Vervaeke, Michael; Volckaerts, Bart; Vynck, Pedro

    2005-01-01

    In this work we present the development of beam monitoring devices consisting of thin CsI(Tl) films deposited on Aluminium support layers. The light emitted by the scintillating layer during the beam irradiation is measured by a CCD-camera. In a first prototype a thin Aluminium support layer of 6 micron allows the ion beam to easily pass through without significant energy loss and scattering effects. Therefore it turns out to be a non-destructive monitoring device to characterize on-line beam shape and beam position without interfering with the rest of the irradiation process. A second device consists of an Aluminium support layer which is thick enough to completely stop the impinging ions allowing to monitor at the same time the beam profile and the beam current intensity. Some samples have been coated by a 100 Å protective layer to prevent the film damage by atmosphere exposition. In this contribution we present our experimental results obtained by irradiating the samples with proton beams at 8.3 and 62 Me...

  14. Beam Studies Made with the SPS Ionization Profile Monitor

    CERN Document Server

    Ferioli, G; Koopman, J; Roncarolo, F

    2003-01-01

    During the last two years of SPS operation, investigations were pursued on the ability of the SPS ionization profile monitor prototype to fulfill different tasks. It is now established that the instrument can be used for injection matching tuning, by turn to turn recording of the beam size after the injection. Other applications concern beam size measurements on beams ranging from an individual bunch to a nominal SPS batch foreseen for injection into the LHC (288 bunches). By continuously tracking throughout the SPS acceleration cycle from 26 GeV to 450 GeV the evolution of parameters associated to the beam size, it is possible to explain certain beam behaviour. Comparisons are also made at different beam currents and monitor gains with measurements made with the wire scanners. Data are presented and discussed, and the possible implementation of new features is suggested in order to further improve the consistency of the measurements.

  15. Low frequency processing for PSR beam position monitors

    International Nuclear Information System (INIS)

    The beam is injected into the Proton Storage Ring (PSR) as a train of sub-nanosecond pulses at the linac frequency of 201.25 MHz. This frequency component is sensed by 20 pairs of 200 MHz stripline beam position monitors and multiplexed to an autocorrelation position processor. The analog position information is sampled, digitized and stored under the control of timing circuits. Beam position histograms from sets of monitors are displayed in the control room. Measurements show that the amplitude of the 200 MHz component is constant during the fill indicating that the strength of the most recently injected beam does not drift during the fill. This structure begins to disappear 20 to 20 turns after a particular batch of beam has been injected. The low frequency components, however, persist and might be used to measure the position of the accumulated beam. We report calculations and experimental results for some low frequency processing systems

  16. A new luminescence beam profile monitor for intense proton and heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Tsang,T.; Bellavia, S.; Connolly, R.; Gassner, D.; Makdisi, Y.; Russo, T.; Thieberger, P.; Trbojevic, D.; Zelenski, A.

    2008-10-01

    A new luminescence beam profile monitor is realized in the polarized hydrogen gas jet target at the Relativistic Heavy Ion Collider (RHIC) facility. In addition to the spin polarization of the proton beam being routinely measured by the hydrogen gas jet, the luminescence produced by beam-hydrogen excitation leads to a strong Balmer series lines emission. A selected hydrogen Balmer line is spectrally filtered and imaged to produce the transverse RHIC proton beam shape with unprecedented details on the RHIC beam profile. Alternatively, when the passage of the high energy RHIC gold ion beam excited only the residual gas molecules in the beam path, sufficient ion beam induced luminescence is produced and the transverse gold ion beam profile is obtained. The measured transverse beam sizes and the calculated emittances provide an independent confirmation of the RHIC beam characteristics and to verify the emittance conservation along the RHIC accelerator. This optical beam diagnostic technique by making use of the beam induced fluorescence from injected or residual gas offers a truly noninvasive particle beam characterization, and provides a visual observation of proton and heavy ion beams. Combined with a longitudinal bunch measurement system, a 3-dimensional spatial particle beam profile can be reconstructed tomographically.

  17. Optical Beam Timing Monitor Experiments at the Advanced Light Source

    OpenAIRE

    Byrd, John; De Santis, Stefano; Wilcox, Rusell; Yan, Yin

    2008-01-01

    We present the initial results of an experimental study of a beam timing monitor based on an optoelectronic technique. This technique uses the electrical signal from a beam position monitor to modulate the amplitude of a train of laser pulses, converting timing jitter into an amplitude jitter. This modulation is then measured with a photodetector and sampled by a fast ADC. This approach has already demonstrated sub-100 fs resolution and promises even better results. Additionally, we are ...

  18. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Abrams, Robert [MUONS Inc., Batavia; Dinkel, Holly [U. Missouri, Columbia; Freemire, Ben [IIT, Chicago; Johnson, Rolland [MUONS Inc., Batavia; Kazakevich, Grigory [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  19. Simulations of LEIR Injection Line Beam Position Monitors

    CERN Document Server

    Maltseva, Mariya

    2016-01-01

    In this paper sensitivity characteristics of a beam position monitor are described. Characteristics are obtained during the simulations in CST Studio, the results are compared with the calculated values. The results for a low-beta beam and with a wire are compared.

  20. Beam monitor system for high-energy beam transportation at HIMAC

    International Nuclear Information System (INIS)

    Heavy-Ion Medical Accelerator in Chiba (HIMAC) provides ion beams for radiotherapy of cancers and for other basic researches. High-energy beam transport lines deliver the beams to three treatment rooms and two experiment rooms with the aid of 41 beam monitor units. Each monitor unit consists of a wire grid as a profile monitor, or a combined unit in which the wire grid and a parallel plate ionization chamber are united for an additional measurement of a beam intensity. They are operated in a mixed gas of 80% Ar and 20% CO2. The gas gain of the wire grid achieves about 8000 at an applied voltage of -2700 V. Dynamic ranges of the wire gird and the parallel plate ionization chamber were measured to be 8x105 and 1x106 in test using ion beams, respectively. A control system of these monitor units offers easy operation, so that operators are almost free from miss-operations. The monitor units are interlocked with a system which protects patients from the undesired irradiation. Five wire grids are used for continuously monitoring the beam during treatments, which play a role in keeping qualities of the treatments. The monitor system has been designed to meet requirements for medical uses, and works in a stable and reliable manner and satisfies the requirements. (author)

  1. Fast beam condition monitor for CMS: Performance and upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Jessica L., E-mail: jessica.lynn.leonard@desy.de [DESY, 15738 Zeuthen (Germany); Bell, Alan [DESY, 15738 Zeuthen (Germany); Burtowy, Piotr [Gdansk University of Technology, 80-233 Gdansk (Poland); Dabrowski, Anne [CERN, 1211 Geneva 23 (Switzerland); Hempel, Maria [DESY, 15738 Zeuthen (Germany); Brandenburg Technical University, 03046 Cottbus (Germany); Henschel, Hans; Lange, Wolfgang [DESY, 15738 Zeuthen (Germany); Lohmann, Wolfgang [DESY, 15738 Zeuthen (Germany); Brandenburg Technical University, 03046 Cottbus (Germany); Odell, Nathaniel [Northwestern University, Evanston, IL, 60208 (United States); Penno, Marek [DESY, 15738 Zeuthen (Germany); Pollack, Brian [Northwestern University, Evanston, IL, 60208 (United States); Przyborowski, Dominik [AGH University of Science and Technology, 30-059 Krakow (Poland); Ryjov, Vladimir [CERN, 1211 Geneva 23 (Switzerland); Stickland, David [Princeton University, Princeton, NJ, 08540 (United States); Walsh, Roberval [DESY, 22607 Hamburg (Germany); Warzycha, Weronika [University of Warsaw, 00-927 Warsaw (Poland); Zagozdzinska, Agnieszka [Warsaw University of Technology, 00-661 Warsaw (Poland)

    2014-11-21

    The CMS beam and radiation monitoring subsystem BCM1F (Fast Beam Condition Monitor) consists of 8 individual diamond sensors situated around the beam pipe within the pixel detector volume, for the purpose of fast bunch-by-bunch monitoring of beam background and collision products. In addition, effort is ongoing to use BCM1F as an online luminosity monitor. BCM1F will be running whenever there is beam in LHC, and its data acquisition is independent from the data acquisition of the CMS detector, hence it delivers luminosity even when CMS is not taking data. A report is given on the performance of BCM1F during LHC run I, including results of the van der Meer scan and on-line luminosity monitoring done in 2012. In order to match the requirements due to higher luminosity and 25 ns bunch spacing, several changes to the system must be implemented during the upcoming shutdown, including upgraded electronics and precise gain monitoring. First results from Run II preparation are shown. - Highlights: • BCM1F uses diamond sensors to measure flux of beam halo and collision products. • The system performed well as a standalone luminometer during LHC Run I. • The high hit rate and radiation post-upgrade require improvements to BCM1F. • Fast electronics have been developed for signal shaping and data readout. • Data from BCM1F will be integrated into online luminosity measurement.

  2. Fast beam condition monitor for CMS: Performance and upgrade

    International Nuclear Information System (INIS)

    The CMS beam and radiation monitoring subsystem BCM1F (Fast Beam Condition Monitor) consists of 8 individual diamond sensors situated around the beam pipe within the pixel detector volume, for the purpose of fast bunch-by-bunch monitoring of beam background and collision products. In addition, effort is ongoing to use BCM1F as an online luminosity monitor. BCM1F will be running whenever there is beam in LHC, and its data acquisition is independent from the data acquisition of the CMS detector, hence it delivers luminosity even when CMS is not taking data. A report is given on the performance of BCM1F during LHC run I, including results of the van der Meer scan and on-line luminosity monitoring done in 2012. In order to match the requirements due to higher luminosity and 25 ns bunch spacing, several changes to the system must be implemented during the upcoming shutdown, including upgraded electronics and precise gain monitoring. First results from Run II preparation are shown. - Highlights: • BCM1F uses diamond sensors to measure flux of beam halo and collision products. • The system performed well as a standalone luminometer during LHC Run I. • The high hit rate and radiation post-upgrade require improvements to BCM1F. • Fast electronics have been developed for signal shaping and data readout. • Data from BCM1F will be integrated into online luminosity measurement

  3. High-speed screen beam-profile-monitor system for high-energy beam-transport line at the HIMAC

    International Nuclear Information System (INIS)

    A screen monitor system was developed for beam profile monitors at the new High-Energy Beam-Transport (HEBT) section out the HIMAC. This monitor consists of the very thin fluorescent screen and the high-speed CCD camera. In addition to perform high-speed and high-resolution, this monitor does not almost destroy the beam. (author)

  4. Beam Position Monitor at the PLS BTL

    CERN Document Server

    Kim, Sung-Chul; Han, Yeung-Jin; Tae Kim, Do; Woo Lee, Wol; Yun Huang Jung

    2005-01-01

    Electron Linac at the Pohnag Accelerator Laboratory (PAL) has been operated continuously as the full energy injector for storage ring. Linac and storage ring energy has been 2.0 GeV since Dec. 1994, and 2.5 GeV since Oct. 2002. In Aug. 2004, thirteen BPMs are newly installed at BTL(Beam Transport Line) for beam trajectory measurement and feedback. These BPMs consist of 100mm strip-line electrodes in 150mm long chamber, and 500MHz log-ratio signal processing circuits. BPM data acquisition system is developed as EPICS IOC using NI S-series data acquisition board and NI LabView 7.1. BTL BPMs will be used for optic correction and beam energy feedback for PLS beam injection. This paper describes on design, test results, installation and data acquisition system of the PLS BTL BPM.

  5. The Fermilab Main Injector: high intensity operation and beam loss control

    CERN Document Server

    Brown, Bruce C; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-01-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at ~400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  6. Transient beam losses in the LHC injection kickers from micron scale dust particles

    CERN Document Server

    Goddard, B; Baer, T; Barnes, M J; Cerutti, F; Ferrari, A; Garrel, N; Gerardin, A; Guinchard, M; Lechner, A; Masi, A; Mertens, V; Morón Ballester, R; Redaelli, S; Uythoven, J; Vlachoudis, V; Zimmermann, F

    2012-01-01

    Transient beam losses on a time scale of a few ms have been observed in the LHC injection kickers, occurring mainly shortly after beam injection with a strong correlation in time to the kicker pulsing. The beam losses, which have at times affected LHC availability, are attributed to micron scale ceramic dust particles detached from the alumina beam pipe and accelerated into the beam. The beam related observations are described, together with laboratory measurements of beam pipe contamination and kicker vibration, simulations of electric field in the beam pipe and the basic dynamic model. Energy deposition simulations modelling the beam losses are presented and compared to measurement. Extrapolations to future LHC operation at higher intensities and energies are made, and prospects for mitigation are discussed.

  7. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  8. Identification and Classification of Beam Loss Patterns in the Large Hadron Collider

    CERN Document Server

    Panagiotis, Theodoropoulos; Redaelli, Stefano; Herbster, Mark

    The Large Hadron Collider, is the largest particle accelerator ever built, achieving record beam energy and beam intensity. Beam losses are unavoidable and can risk the safety of accelerator’s components. Beam loss maps are used to validate the collimation system, designed to protect the accelerator against beam losses. The complexity of this system requires well defined inspection methods and well defined case studies that ensure normal operation and efficient performance evaluation. In this work, enhancements are proposed to the existing validation methods with extensions towards automating the inspection mechanisms, introducing pattern recognition and statistical learning methods.

  9. Development of a beam condition monitor for use in experiments at the CERN Large Hadron Collider using synthetic diamond

    CERN Document Server

    Fernández-Hernando, L; Ilgner, C; MacPherson, A; Oh, A; Pernegger, H; Pritchard, T; Stone, R; Worm, S

    2004-01-01

    The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams, each with a store energy about 350MJ; enough to melt 550kg of copper. If there is failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor last increments of particle flux near the interaction point and if necessary, to generate an abort signal to the LHC accelerator control, to dump the beams. Due to its radiation hardness and minimal services requirements, synthetic CVD diamond is being considered as BCM sensor option. (12 refs).

  10. Study of an integrated electronic monitor for neutron beams

    International Nuclear Information System (INIS)

    Many neutron beams monitors in 10 keV - 50 keV range are perturbed by gamma radiation impact. This new monitor uses two silicon (junction) diodes operating coincidence detection, combined with an electronic threshold to eliminate gamma background noise. The results and analyses presented here only concern feasibility studies. (D.L.)

  11. The development of beam current monitors in the APS

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) is a third-generation 7-GeV synchrotron radiation source. The precision measurement of beam current is a challenging task in high energy accelerators, such as the APS, with a wide range of beam parameters and complicated noise, radiation, and thermal environments. The beam pulses in the APS injector and storage ring have charge ranging from 50pC to 25nC with pulse durations varying from 30ps to 30ns. A total of nine non- intercepting beam current monitors have been installed in the APS facility (excluding those in the linac) for general current measurement. In addition, several independent current monitors with specially designed redundant interlock electronics are installed for personnel safety and machine protection. This paper documents the design and development of current monitors in the APS,. discusses the commissioning experience in the past year, and presents the results of recent operations

  12. High-resolution phosphor screen beam profile monitor

    International Nuclear Information System (INIS)

    A high-resolution luminescent screen beam profile monitor was developed to allow viewing of both conventional large diameter SLAC e+/e- beams, and also collider rf-bunches having small transverse spatial extent, with one instrument. The principal features of the monitor are described. They include the two-power magnification system offering magnifications of 12 and 78X, respectively; the reticle grid which is optically superimposed on the screen image by a cube beam splitter; selection of a suitable camera; and the Al2O3(Cr) phosphor screen. A simplified version of the monitor for viewing of only micron-sized beams for applications in the collider arcs and final focus regions and achieving a magnification of approx. 40X, coupled with a resolution of approx. 20μm is also presented. 4 refs., 4 figs

  13. Beam profile monitor using alumina screen and CCD camera

    International Nuclear Information System (INIS)

    A pair of beam profile monitors using alumina ceramic screens (Al2O3) and CCD cameras has been developed for diagnosis of a linac beam at the 1.3 GeV electron synchrotron of the Institute for Nuclear Study, the University of Tokyo (INS-ES). Since both the light decay-time of the screen and a shutter speed of the camera are relatively short, about 10 msec or less and 1 msec, respectively, this system is able to measure the beam profile for each pulse of the linac beam operated at a repetition rate of 21.5 Hz. Detailed analysis of the beam profile is made using the stored data on the personal computer. On the other hand, a light spot on the screen is displayed directly on a monitor display. (author)

  14. LASER-BASED PROFILE MONITOR FOR ELECTRON BEAMS

    International Nuclear Information System (INIS)

    High performance TeV energy electron / positron colliders (LC) are the first machines to require online, non-invasive beam size monitors for micron and sub-micron for beam phase space optimization. Typical beam densities in the LC are well beyond the threshold density for single pulse melting and vaporization of any material, making conventional wire scanners ineffective. Using a finely focused, diffraction limited high power laser, it is possible to devise a sampling profile monitor that, in operation, resembles a wire scanner. Very high resolution laser-based profile monitors have been developed and tested, first at FFTB (SLAC) and later at SLC and ATF. The monitor has broad applicability and we review here the technology, application and status of ongoing research programs

  15. 1 nA Beam position monitor

    International Nuclear Information System (INIS)

    A new BPM system, based on resonant cavities, has been developed for measuring the transverse position of very low-intensity electron beams delivered to Experimental Hall B at the Continuous Electron Beam Accelerator Facility (CEBAF) in Newport News. VA. The system requirements called for measuring down to 1 nA with a 100 m m resolution. The actual system is much better: it can measure down to 100 pA at the 100 m m required resolution. A 100 pA beam yields about 1 electron per bunch. Each 1 nA BPM utilizes three resonant RF cavities to determine the position of the beam: one cavity sensitive to X position, a second cavity sensitive to Y position, and a third cavity which measures intensity. The position cavities operate at room temperature in a dipole type mode at 1497 MHz and contain internal field perturbing rods in an arrangement similar to that of the CEBAF rf Separator cavities. The position cavities are electron beam welded assemblies made of copper plated stainless steel. The RF output signal from each cavity is processed using a down-converter and a DSP based commercial lock-in amplifier operating at 100 kHz. The lock-in amplifiers connect to the EPICS control system via an IEEE 488 bus. System features under development include intensity and position modulation measurement capabilities. This paper provides measured performance results and an updated overview of the installed and operational 1 nA BPM system. copyright 1998 American Institute of Physics

  16. Beam position measurements of Indus-2 using X-Ray beam position monitor

    International Nuclear Information System (INIS)

    A staggered pair metal blade X-ray beam position monitor (XBPM) is designed, fabricated and commissioned on Indus-2 bending magnet front end. Calibration of XBPM is done by scanning the metal blades in the path of synchrotron radiation and by giving controlled electron asymmetric bump. The vertical beam position stability of the source measured during various injections and storages are reported.

  17. A phase-space beam position monitor for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Samadi, Nazanin, E-mail: nazanin.samadi@usask.ca [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada); Bassey, Bassey; Martinson, Mercedes [University of Saskatchewan, 116 Science Place, Saskatoon, SK (Canada); Belev, George; Dallin, Les; Jong, Mark de [Canadian Light Source, 44 Innovation Boulevard, Saskatoon, SK (Canada); Chapman, Dean [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada)

    2015-06-25

    A system has been developed to measure the vertical position and angle of the electron beam at a single location from a synchrotron source. The system uses a monochromator tuned to the absorption edge of a contrast material and has a sensitivity comparable with other beam position monitors. The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered

  18. Video-based beam position monitoring at CHESS

    Science.gov (United States)

    Revesz, Peter; Pauling, Alan; Krawczyk, Thomas; Kelly, Kevin J.

    2012-10-01

    CHESS has pioneered the development of X-ray Video Beam Position Monitors (VBPMs). Unlike traditional photoelectron beam position monitors that rely on photoelectrons generated by the fringe edges of the X-ray beam, with VBPMs we collect information from the whole cross-section of the X-ray beam. VBPMs can also give real-time shape/size information. We have developed three types of VBPMs: (1) VBPMs based on helium luminescence from the intense white X-ray beam. In this case the CCD camera is viewing the luminescence from the side. (2) VBPMs based on luminescence of a thin (~50 micron) CVD diamond sheet as the white beam passes through it. The CCD camera is placed outside the beam line vacuum and views the diamond fluorescence through a viewport. (3) Scatter-based VBPMs. In this case the white X-ray beam passes through a thin graphite filter or Be window. The scattered X-rays create an image of the beam's footprint on an X-ray sensitive fluorescent screen using a slit placed outside the beam line vacuum. For all VBPMs we use relatively inexpensive 1.3 Mega-pixel CCD cameras connected via USB to a Windows host for image acquisition and analysis. The VBPM host computers are networked and provide live images of the beam and streams of data about the beam position, profile and intensity to CHESS's signal logging system and to the CHESS operator. The operational use of VBPMs showed great advantage over the traditional BPMs by providing direct visual input for the CHESS operator. The VBPM precision in most cases is on the order of ~0.1 micron. On the down side, the data acquisition frequency (50-1000ms) is inferior to the photoelectron based BPMs. In the future with the use of more expensive fast cameras we will be able create VBPMs working in the few hundreds Hz scale.

  19. The LANSCE Low Momentum Beam Monitor

    CERN Document Server

    Merl, R

    2004-01-01

    A diagnostic has been developed at the Los Alamos Neutron Science Center (LANSCE) for the purpose of identifying low momentum beam tails in the linear accelerator. These tails must be eliminated in order to maintain the transverse and longitudinal beam size. Instead of the currently used phosphor camera system, this instrument consists of a Multi Wire Proportional Chamber (MWPC) front end coupled to an EPICS compliant VME-based electronics package. Low momentum tails are detected with a resolution of 5 mm in the MWPC at a high dispersion point near a bending magnet. While phosphor is typically not sensitive in the nano amp range, the MWPC is sensitive down to about a pico amp. The electronics package processes the signals from each of the MWPC wires to generate an array of beam currents at each of the lower energies. The electronics has an analog front end with a high-speed analog to digital converter for each wire. Data from multiple wires are processed with an embedded digital signal processor and results p...

  20. The Long-Term Beam Losses in the CERN Injector Chain

    CERN Document Server

    Gilardoni, Simone; Benedetto, Elena; Damerau, Heiko; Forte, Vincenzo; Giovannozzi, Massimo; Goddard, Brennan; Hancock, Steven; Hanke, Klaus; Huschauer, Alexander; Kowalska, Magdalena; Mcateer, Meghan Jill; Metral, Elias; Mikulec, Bettina; Papaphilippou, Yannis; Rumolo, Giovanni; Sterbini, Guido; Wasef, Raymond; Arduini, Gianluigi; Meddahi, Malika; Chapochnikova, Elena

    2015-01-01

    For the production of the LHC type beams, but also for the high intensity ones, the budget allocated to losses in the CERN injector chain is maintained as tight as possi- ble, in particular to keep as low as possible the activation of the different machine elements. Various beam dynamics effects, like for example beam interaction with betatronic resonances, beam instabilities, but also reduced efficiency of the RF capture processes or RF noise, can produce losses even on a very long time scale. The main different mecha- nisms producing long term losses observed in the CERN injectors, and their cure or mitigation, will be revised.

  1. Size modulated transition in the fluid-structure interaction losses in nano mechanical beam resonators

    Science.gov (United States)

    Vishwakarma, S. D.; Pandey, A. K.; Parpia, J. M.; Verbridge, S. S.; Craighead, H. G.; Pratap, R.

    2016-05-01

    An understanding of the dominant dissipative mechanisms is crucial for the design of a high-Q doubly clamped nanobeam resonator to be operated in air. We focus on quantifying analytically the viscous losses—the squeeze film damping and drag force damping—that limit the net quality factor of a beam resonator, vibrating in its flexural fundamental mode with the surrounding fluid as air at atmospheric pressure. Specifically, drag force damping dominates at smaller beam widths and squeeze film losses dominate at larger beam widths, with no significant contribution from structural losses and acoustic radiation losses. The combined viscous losses agree well with the experimentally measured Q of the resonator over a large range of beam widths, within the limits of thin beam theory. We propose an empirical relation between the maximum quality factor and the ratio of maximum beam width to the squeeze film air gap thickness.

  2. Development of digital beam position monitor based on software radio

    International Nuclear Information System (INIS)

    Digital beam position monitor processor is the key part of a beam position system. A BPM processor based on software radio is much better than traditional processors in terms of the resolution and flexibility. In this paper, we report technical specifications and design considerations of the digital beam position monitor developed at Shanghai Synchrotron Radiation Facility (SSRF). The turn-by-turn electronic resolution of the processor is better than 1.5 μm, when the input power is larger than -30 dBm, and the resolution is better than 2 μm in a test in the SSRF storage ring, with the beam current of over 150 mA. (authors)

  3. Electronics and Calibration system for the CMS Beam Halo Monitor

    CERN Document Server

    Tosi, Nicolò; Fabbri, Franco L; Finkel, Alexey; Orfanelli, Stella; Loos, R; Montanari, Alessandro; Rusack, R; Stickland, David P

    2014-01-01

    In the context of increasing luminosity of LHC, it will be important to accurately measure the Machine Induced Background. A new monitoring system will be installed in the cavern of the Compact Muon Solenoid (CMS) experiment for measuring the beam background at high radius. This detector is composed of synthetic quartz Cherenkov radiators, coupled to fast photomultiplier tubes (PMT). The readout chain of this detector will make use of many components developed for the Phase 1 upgrade to the CMS Hadron Calorimeter electronics, with a dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal will be digitized by a charge integrating ASIC (QIE10), providing both the signal rise time and the charge integrated over one bunch crossing. The backend electronics will record bunch-by-bunch histograms, which will be published to CMS and the LHC using the newly designed CMS beam instrumentation specific DAQ. A calibration monitoring system has been designed to generate triggered pulses of...

  4. Low and high intensity beam monitoring and tracking

    CERN Document Server

    Lietti, D.; Bolognini, D.; Colombo, J.; Hasan, S.; Mattera, A.; Mozzanica, A.; Prest, M.; Schmitt, B.; Vallazza, E.

    Several detector types have been designed and assembled in order to monitor charged particle beams in a wide range of intensities: silicon microstrip detectors for high precision tracking (spatial resolution better than 5 μm), a scintillating fiber tracker with multianode photomultiplier readout for coarse but fast monitoring, a microstrip silicon detector readout by a counting ASIC to monitor very high intensity beams. These detectors and their readout electronics have been characterized at the BTF (Beam Test Facility) of the INFN National Laboratories of Frascati and used on the H8 line at the CERN SPS as tracking media for the data taking of the H8RD22 collaboration. The paper describes the results obtained in terms of spatial resolution and maximum counting rates.

  5. Beam monitor system for high-energy beam transportation at HIMAC

    CERN Document Server

    Torikoshi, M; Takada, E; Kanai, T; Yamada, S; Ogawa, H; Okumura, K; Narita, K; Ueda, K; Mizobata, M

    1999-01-01

    Heavy-Ion Medical Accelerator in Chiba (HIMAC) provides ion beams for radiotherapy of cancers and for other basic researches. High-energy beam transport lines deliver the beams to three treatment rooms and two experiment rooms with the aid of 41 beam monitor units. Each monitor unit consists of a wire grid as a profile monitor, or a combined unit in which the wire grid and a parallel plate ionization chamber are united for an additional measurement of a beam intensity. They are operated in a mixed gas of 80% Ar and 20% CO sub 2. The gas gain of the wire grid achieves about 8000 at an applied voltage of -2700 V. Dynamic ranges of the wire gird and the parallel plate ionization chamber were measured to be 8x10 sup 5 and 1x10 sup 6 in test using ion beams, respectively. A control system of these monitor units offers easy operation, so that operators are almost free from miss-operations. The monitor units are interlocked with a system which protects patients from the undesired irradiation. Five wire grids are use...

  6. The Beam Conditions Monitor of the LHCb Experiment

    OpenAIRE

    Ilgner, Ch.; Lieng, M. Domke M.; Nedos, M.; Sauerbrey, J.; Schleich, S; Spaan, B.; Warda, K.; Wishahi, J.

    2010-01-01

    The LHCb experiment at the European Organization for Nuclear Research (CERN) is dedicated to precision measurements of CP violation and rare decays of B hadrons. Its most sensitive components are protected by means of a Beam Conditions Monitor (BCM), based on polycrystalline CVD diamond sensors. Its configuration, operation and decision logics to issue or remove the beam permit signal for the Large Hadron Collider (LHC) are described in this paper.

  7. Pin diode calibration - beam overlap monitoring for low energy cooling

    Energy Technology Data Exchange (ETDEWEB)

    Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    We were trying to address the question whether or not the Pin Diodes, currently installed approximately 1 meter downstream of the RHIC primary collimators, are suitable to monitor a recombination signal from the future RHIC low energy cooling section. A maximized recombination signal, with the Au+78 ions being lost on the collimator, will indicate optimal Au-electron beam overlap as well as velocity matching of the electron beam in the cooling section.

  8. Charged particle beam current monitoring tutorial

    International Nuclear Information System (INIS)

    A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed

  9. Ribbon target assembly using carbon graphite for secondary emission type beam profile monitor

    International Nuclear Information System (INIS)

    We developed a secondary emission type beam profile monitor with graphite ribbons as a beam target. The graphite is excellent in endurance against heat load, and that they are thin as 1.6-2.0 micron and low z (=6) is advantage for reducing beam loss. Furthermore, since ribbons emits larger amount of electrons than ordinal metal wires because of larger surface, the monitor has higher sensitivity. On the other hands, in case of multi-ribbon type, uniformity of secondary electron emission is required for accurate measurement. For the uniform emission, not only surface homogeneity, but also evenness for each ribbon width is needed. A suitable manufacturing method to make ribbon target from graphite-foil, and emission uniformity has been studied. (author)

  10. EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.

    Energy Technology Data Exchange (ETDEWEB)

    BALAKIN,V.; BAZHAN,A.; LUNEV,P.; SOLYAK,N.; VOGEL,V.; ZHOGOLEV,P.; LISITSYN,A.; YAKIMENKO,V.

    1999-03-29

    Future Linear Colliders have hard requirements for the beam transverse position stability in the accelerator. A beam Position Monitor (BPM) with the resolution better than 0.1 micron in the single bunch regime is needed to control the stability of the beam position along the linac. Proposed BPM is based on the measurement of the asymmetrical mode excited by single bunch in the cavity. Four stages of signal processing (space-, time-, frequency- and phase-filtering providing the required signal-to-noise ratio) are used to obtain extremely high resolution. The measurement set-up was designed by BINP and installed at ATF/BNL to test experimentally this concept. The set-up includes three two-coordinates BPM's at the frequency of 13.566 GHz, and reference intensity/phase cavity. BPM's were mounted on support table. The two-coordinates movers allow to move and align BPM's along the straight line, using the signals from the beam. The position of each monitor is controlled by the sensors with the accuracy 0.03 micron. The information from three monitors allows to exclude angle and position jitter of the beam and measure BPM resolution. In the experiments the resolution of about 0.15 micron for 0.25 nC beam intensity was obtained, that is close to the value required.

  11. Practical application High-Tc SQUID beam current monitor

    International Nuclear Information System (INIS)

    To measure the DC current of heavy-ion beams non-destructively at high resolution, we have developed a high critical temperature (HTc) superconducting quantum interference device (SQUID) beam current monitor for use in the radioactive isotope beam factory (RIBF) at RIKEN. Unlike at other existing facilities, a low vibration, pulse-tube refrigerator cools the HTc fabrications including the SQUID in such a way that the size of the system is reduced and the running costs are lowered. Last year, the magnetic shielding system has been greatly reinforced. The new strong magnetic shielding system can attenuate the external magnetic noise to 10-10. Aiming at its practical use for acceleration operation, the prototype HTc SQUID monitor was disassembled, exchange the improved parts and re-assembled. Beginning this year, we have installed the HTc SQUID monitor in the beam transport line in the RIBF. Here we report the present details of the developed HTc SQUID monitor system and the results of the beam measurement. (author)

  12. A new digital beam position monitor in SSRF

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The newly developed Digital Beam Position Monitor (DBPM) system is introduced. The DBPM system differs with the conventional beam position monitor system in the use of DSP chips and the digital signal processing technology. It can be programmed on-line to select operation modes through EPICS control panel, and to measure various parameters of the third generation synchrotron radiation facility. This DBPM system can be used in the pre-injector LINAC, the transfer lines, the booster synchrotron and the storage ring. The electronic parameters of the DBPM system itself have been measured also.

  13. Design of the AGS Booster Beam Position Monitor electronics

    International Nuclear Information System (INIS)

    The operational requirements of the AGS Booster Beam Position Monitor system necessitate the use of electronics with wide dynamic range and broad instantaneous bandwidth. Bunch synchronization is provided by a remote timing sequencer coupled to the local ring electronics via digital fiber-optic links. The Sequencer and local ring circuitry work together to provide single turn trajectory or average orbit and intensity information, integrated over 1 to 225 bunches. Test capabilities are built in for the purpose of enhancing BPM system accuracy. This paper describes the design of the Booster Beam Position Monitor electronics, and presents performance details of the front end processing, acquisition and timing circuitry

  14. Medical beam monitor-Pre-clinical evaluation and future applications

    International Nuclear Information System (INIS)

    Future medical ion beam applications for cancer therapy which are based on scanning technology will require advanced beam diagnostics equipment. For a precise analysis of beam parameters we want to resolve time structures in the range of microseconds to nanoseconds. A prototype of an advanced beam monitor was developed by University of Applied Sciences Wiener Neustadt and its research subsidiary Fotec in co-operation with CERN RD42, Ohio State University and the Jozef Stefan Institute in Ljubljana. The detector is based on polycrystalline Chemical Vapor Deposition (pCVD) diamond substrates and is equipped with readout electronics up to 2 GHz analog bandwidth. In this paper we present the design of the pCVD-detector system and results of tests performed in various particle accelerator based facilities. Measurements performed in clinical high energy photon beams agreed within 1.2% with results obtained by standard ionization chambers

  15. Performance of an rf beam monitor on the NBS-Los Alamos racetrack microtron

    International Nuclear Information System (INIS)

    A prototype rf beam-position, current, and phase monitor has been used on the 100-keV injector beamline of the racetrack microtron (RTM) where performance was measured with the chopped and bunched beam. This monitor works with both a pulsed beam and a cw beam. The pulsed beam consists of beam pulses with a FWHM of 40 ns. The rf beam monitor was tested with beam currents from approx. 50 to 600 μA. The rf beam monitor will be described and its performance will be reported. 6 refs., 5 figs

  16. Beam Position and Phase Monitor - Wire Mapping System

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Heath A [Los Alamos National Laboratory; Shurter, Robert B. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory

    2012-04-10

    The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

  17. Collective monitors for high-current pulse electron beam diagnostics

    International Nuclear Information System (INIS)

    A collector monitor for high-current pulsed electron beams at average power of 100 W and pulse current of 100 A has been developed. The monitor comprises a Faraday cup, profile monitor, sector diaphragm, energy detector. The collector was fixed on a brass radiator transformed into a rod. The rod ensures reliable and electric contact of the collector with the ''earth'' and small RC of this line. Such design permits to stabilize the heat mode of the collector without utilization of external cooling. The monitors have been tested in electron beams at head load up to 100 W during 40 hours. Wear at the expense of evaporation, microexplosions were not observed. Accuracy of current measuring made up 5-10% for absolute and 1-2% for relative measurements

  18. Particle Rate and Host Accelerator Beam Loss on the MICE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Adam James [Imperial Coll., London; Imperial College, London (United Kingdom)

    2011-10-01

    A study is presented of particle rates in the MICE Muon Beamline and their relationship to beam loss produced in ISIS. A brief overview of neutrino physics is presented, together with a discussion on the Neutrino Factory as a motivation for MICE. An overview of MICE itself is then presented, highlighting the need for a systematic understanding of the relationship between the MICE target parameters, ISIS beam loss, and MICE particle rate. The variation of beam loss with target depth is examined and observed to be non-linear. The variation of beam loss with respect to the target dip time in the ISIS cycle is examined and observed to be approximately linear for dip times between 11.1 ms and 12.6 ms after ISIS injection, before tailing at earlier dip times. The variation of beam loss with particle rate is also observed to follow an approximately linear relationship from 0.05 V.ms to 4.7 V.ms beam loss, with a further strong indication that this continues up to 7.1 V.ms. Particle identification using time-of-flight data is used to give an insight into the relative abundances of each particle species present in the MICE beam. Estimates of muon rate are then produced as a function of beam loss. At a level of 2 V.ms beam loss ~10:9 muons per spill for a 3.2 ms spill with negative π → μ optics, and ~31:1 muons per 1 ms spill with positive π → μ optics are observed. Simulations using the ORBIT particle tracking code of the beam loss distributions around the ISIS ring, caused by the MICE target, are also presented and the implications for MICE running discussed.

  19. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    Science.gov (United States)

    Jang, Hyojae; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok

    2016-02-01

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

  20. PAL-XFEL cavity beam position monitor pick-up design and beam test

    Science.gov (United States)

    Lee, Sojeong; Park, Young Jung; Kim, Changbum; Kim, Seung Hwan; Shin, Dong Cheol; Han, Jang-Hui; Ko, In Soo

    2016-08-01

    As an X-ray Free Electron Laser, PAL-XFEL is about to start beam commissioning. X-band cavity beam position monitor (BPM) is used in the PAL-XFEL undulator beam line. Prototypes of cavity BPM pick-up were designed and fabricated to test the RF characteristics. Also, the beam test of a cavity BPM pick-up was done in the Injector Test Facility (ITF). In the beam test, the raw signal properties of the cavity BPM pick-up were measured at a 200 pC bunch charge. According to the RF test and beam test results, the prototype cavity BPM pick-up design was confirmed to meet the requirements of the PAL-XFEL cavity BPM system.

  1. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho; Hong, In-Seok [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

    2016-02-15

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.

  2. Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

    International Nuclear Information System (INIS)

    A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, development of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described

  3. Full cycle beam diagnostics with an ionization profile monitor

    International Nuclear Information System (INIS)

    The Alternating Gradient Synchrotron Booster at Brookhaven National Laboratory uses an ionization profile monitor to generate profiles of proton and heavy-ion beams. The profile monitor can acquire hundreds of profiles during an acceleration cycle, and then display and store them for analysis. Profiles appear in real time on an oscilloscope-type display, but other visualizations are available as well, namely mountain range and emittance displays. File storage of profile data is simple, as is the storage of moments and emittances

  4. Beam Tests of a Prototype Stripline Beam Position Monitoring System for the Drive Beam of the CLIC Two-beam Module at CTF3

    CERN Document Server

    Benot-Morell, Alfonso; Nappa, Jean-Marc; Vilalte, Sebastien; Wendt, Manfred

    2016-01-01

    In collaboration with LAPP and IFIC, two units of a prototype stripline Beam Position Monitor (BPM) for the CLIC Drive Beam (DB), and its associated readout electronics have been successfully installed and tested in the Two-Beam-Module (TBM) at the CLIC Test Facility 3 (CTF3) at CERN. This paper gives a short overview of the BPM system and presents the performance measured under different Drive Beam configurations.

  5. A calibration procedure for beam monitors in a scanned beam of heavy charged particles.

    Science.gov (United States)

    Jäkel, O; Hartmann, G H; Karger, C P; Heeg, P; Vatnitsky, S

    2004-05-01

    An international code of practice (CoP) for dosimetry based on standards of absorbed dose to water has recently been published by the IAEA [Technical Report Series No. 398, 2000] (TRS-398). This new CoP includes procedures for proton and heavy ion beams as well as all other beam qualities. In particular it defines reference conditions to which dose measurements should refer to. For proton and ion beams these conditions include dose measurements in the center of all possible modulated Bragg peaks. The recommended reference conditions in general are used also for the calibration of beam monitors. For a dynamic beam delivery system using beam scanning in combination with energy variation, like, e.g., at the German carbon ion radiotherapy facility, this calibration procedure is not appropriate. We have independently developed a different calibration procedure. Similar to the IAEA CoP this procedure is based on the measurement of absorbed dose to water. This is translated in terms of fluence which finally results in an energy-dependent calibration of the beam monitor in units of particle number per monitor unit, which is unique for all treatment fields. In contrast to the IAEA CoP, the reference depth is chosen to be very small. The procedure enables an accurate and reliable determination of calibration factors. In a second step, the calibration is verified by measurements of absorbed dose in various modulated Bragg peaks by comparing measured against calculated doses. The agreement between measured and calculated doses is usually better than 1% for homogeneous fields and the mean deviation for more inhomogeneous treatment fields, as they are used for patient treatments, is within 3%. It is proposed that the CoP in general, and in particular the IAEA TRS-398 should include explicit recommendations for the beam monitor calibration. These recommendations should then distinguish between systems using static and dynamic beams. PMID:15191285

  6. 10 Orders of Magnitude Current Measurement Digitisers for the CERN Beam Loss Systems

    CERN Document Server

    Vigano, W; Dehning, B; Kwiatkowski, M; Venturini, G G; Zamantzas, C

    2014-01-01

    A wide range current digitizer card is needed for the acquisition module of the beam loss monitoring systems in the CERN Injector Complex. The fully differential frequency converter allows measuring positive and negative input currents with a resolution of 31nA in an integration window of 2μs. Increasing the integration window, the dynamic range covers 2•1010 were the upper part of the range is converted by measuring directly the voltage drop on a resistor. The key elements of this design are the fully differential integrator and the switches operated by an FPGA. The circuit is designed to avoid any dead time in the acquisition and reliability and failsafe operational considerations are main design goals. The circuit will be discussed in detail and lab and field measurements will be shown.

  7. Propagation of Gaussian beams in the presence of gain and loss

    CERN Document Server

    Graefe, Eva-Maria; Schubert, Roman

    2016-01-01

    We consider the propagation of Gaussian beams in a waveguide with gain and loss in the paraxial approximation governed by the Schr\\"odinger equation. We derive equations of motion for the beam in the semiclassical limit that are valid when the waveguide profile is locally well approximated by quadratic functions. For Hermitian systems, without any loss or gain, these dynamics are given by Hamilton's equations for the center of the beam and its conjugate momentum. Adding gain and/or loss to the waveguide introduces a non-Hermitian component, causing the width of the Gaussian beam to play an important role in its propagation. Here we show how the width affects the motion of the beam and how this may be used to filter Gaussian beams located at the same initial position based on their width.

  8. Multifunctional monitor of beam parameters for a cyclotron

    International Nuclear Information System (INIS)

    The ionization monitor is described designed for on-line monitoring of beam intensity and position in a cyclotron transport channel, and also of beam current pulse form related to a modulation of accelerating voltage and beam energy. The monitor comprises the extracting system in a form of flat capacitor formed by the reflecting electrode and forming grid. To eliminate the effect of slow ionic component the reflecting electrode is provided with an antidynatron grid. The electron component istransmitted to the electron multiplier with a gain factor up to 108 assembled on two microchannel electron plates. Thethreshold monitor sensitivity at a pressure of 10sup(-5)Tor constitutes 10sup(-11) - 10sup(-12) A. Introduction of a special stroboscopic electrode between the electron multiplier and transducer allows one to record timing beam parameters, in particular, microbunches duration and phase position. The complex of electronic equipment for visualization and digital processing of measuring results is constructed on the basis of the CAMAC units and TV set. up

  9. Beam monitoring in radiotherapy and hadron-therapy

    International Nuclear Information System (INIS)

    Radiotherapy techniques have evolved over the past twenty years. For photon beams, the development of tools such as multi leaf collimators, machines such as Cyberknife or tomo-therapy, have improved the conformation of treatments to the tumor volume and lowered maximum dose to healthy tissue. In another register, the use of proton-therapy is expanding in all countries and the development of carbon ions beams for hadron-therapy is also increasing. If techniques improve, the control requirements for the monitoring of the dose administered to patients are always the same. This document presents, first, the ins and outs of the different techniques of external beam radiotherapy: photon treatments, protons and hadrons. Starting from the basis of clinical requirements, it sets the variables to be measured in order to ensure the quality of treatment for the different considered modalities. It then describes some implementations, based on precise and rigorous specifications, for the monitoring and measurement of beams delivered by external beam radiotherapy equipments. Two instrumental techniques are particularly highlighted, plastic scintillators dosimetry for the control of megavoltage photon beams and ionization chamber dosimetry applied to proton-therapy or radiobiology experiments conducted at the GANIL facility. Analyzes and perspectives, based on the recent developments of treatment techniques, are delivered in conclusion and can serve as guide for future instrumental developments. (author)

  10. A high resolution, single bunch, beam profile monitor

    International Nuclear Information System (INIS)

    Efficient linear colliders require very small beam spots to produce high luminosities with reasonable input power, which limits the number of electrons which can be accelerated to high energies. The small beams, in turn, require high precision and stability in all accelerator components. Producing, monitoring and maintaining beams of the required quality has been, and will continue to be, difficult. A beam monitoring system which could be used to measure beam profile, size and stability at the final focus of a beamline or collider has been developed and is described here. The system uses nonimaging bremsstrahlung optics. The immediate use for this system would be examining the final focus spot at the SLAC/FFTB. The primary alternatives to this technique are those proposed by P. Chen / J. Buon, which analyses the energy and angular distributions of ion recoils to determine the aspect ratio of the electron bunch, and a method proposed by Shintake, which measures intensity variation of compton backscattered photons as the beam is moved across a pattern of standing waves produced by a laser

  11. Progress on the development of APS beam position monitoring system

    International Nuclear Information System (INIS)

    This paper describes the development status of the beam position monitoring system for the Advanced Photon Source (APS), a third-generation light source now under construction at Argonne National Laboratory. The accelerator complex will consist of an electron linac, a positron linac, a positron accumulator ring (PAR), an injector synchrotron and a storage ring. For beam position measurement, striplines will be used on the linacs, while button-type pickups will be used on the injector synchrotron and the storage ring. A test stand with a prototype injector synchrotron beam position monitor (BPM) unit has been built, and we present the results of position calibration measurements using a wire. Comparison of the results with theoretical calculations will be presented. The current effort on similar storage ring BPM system measurements will also be discussed. 4 refs., 5 figs., 2 tabs

  12. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  13. First Beam Measurements with the LHC Synchrotron Light Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, Thibaut; /CERN; Bravin, Enrico; /CERN; Burtin, Gerard; /CERN; Guerrero, Ana; /CERN; Jeff, Adam; /CERN; Rabiller, Aurelie; /CERN; Roncarolo, Federico; /CERN; Fisher, Alan; /SLAC

    2012-07-13

    The continuous monitoring of the transverse sizes of the beams in the Large Hadron Collider (LHC) relies on the use of synchrotron radiation and intensified video cameras. Depending on the beam energy, different synchrotron light sources must be used. A dedicated superconducting undulator has been built for low beam energies (450 GeV to 1.5 TeV), while edge and centre radiation from a beam-separation dipole magnet are used respectively for intermediate and high energies (up to 7 TeV). The emitted visible photons are collected using a retractable mirror, which sends the light into an optical system adapted for acquisition using intensified CCD cameras. This paper presents the design of the imaging system, and compares the expected light intensity with measurements and the calculated spatial resolution with a cross calibration performed with the wire scanners. Upgrades and future plans are also discussed.

  14. A button - type beam position monitor design for TARLA facility

    Science.gov (United States)

    Gündoǧan, M. Tural; Kaya, ć.; Yavaş, Ö.

    2016-03-01

    Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC). TARLA is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The TARLA facility is expected to provide two modes, Continuous wave (CW) and pulsed mode. Longitudinal electron bunch length will be changed between 1 and 10 ps. The bunch charge will be limited by 77pC. The design of the Button-type Beam Position Monitor for TARLA IR FEL is studied to operate in 1.3 GHz. Mechanical antenna design and simulations are completed considering electron beam parameters of TARLA. Ansoft HFSS and CST Particle Studio is used to compare with results of simulations.

  15. Beam position monitors for the high brightness lattice

    International Nuclear Information System (INIS)

    Engineering developments associated with the high brightness lattice and the projected change in machine operating parameters will inherently affect the diagnostics systems and devices installed at present in the storage ring. This is particularly true of the beam position monitoring (BPI) system. The new sixteen unit cell lattice with its higher betatron tune values and the limited space available in the redesigned machine straights for fitting standard BPI vessels forces a fundamental re-evaluation of the beam position monitor system. The design aims for the new system are based on accepting the space limitations imposed while still providing the monitor points required to give good radial and vertical closed orbit plots. The locations of BPI's in the redesigned machine straights is illustrated. A description of the new BPI assemblies and their calibration is given. The BPI's use capacitance button type pick-ups; their response is described. (U.K.)

  16. Cryogenic loss monitors with FPGA TDC signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Warner, A.; Wu, J.; /Fermilab

    2011-09-01

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highlight the processing techniques used.

  17. Cryogenic loss monitors with FPGA TDC signal processing

    CERN Document Server

    Warner, A

    2012-01-01

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highligh...

  18. Beam Profile Monitor Tests at the SLAC FFTB^1

    Science.gov (United States)

    Norem, J.; Dawson, J.; Haberichter, W.; Reed, L.; Yang, X.-F.; Spencer, J.; Saleski, M.

    1996-05-01

    The next generation linear colliders require beam sizes as small as 5 nm for efficient collisions between electron and positron beams. The difficulty of producing and maintaining such beams in stable collision means that bunch-to-bunch measurements need to be made quickly and precisely. We are developing a new technique using non-imaging gamma optics having good time resolution and sensitivity to correlations when the expected resolution is a few nm. Apparatus has been set up and made operational in the Final Focus Test Beam at SLAC and we have begun to tune and test components. We will describe this setup and our initial measurements together with Monte Carlo simulations based on using foils and wires (bremsstrahlung) and laser backscattering (Compton) as gamma sources to measure the beam size at IP1 of experiment E144. For the NLC we could also use beamsstrahlung generated by the strong beam-beam interaction at the IP to provide a comparable nonintercepting monitor. \\overline ^1Funded by the US Department of Energy under contracts W-31-109-ENG-38 and DE-AC03-76SF00515.

  19. Status of the Stripline Beam Position Monitor developement for the CLIC Drive Beam

    CERN Document Server

    Benot-Morell, A; Wendt, M; Faus-Golfe, A; Nappa, J M; Vilalte, S; Smith, S

    2013-01-01

    In collaboration with SLAC, LAPP and IFIC, a first prototype of a stripline Beam Position Monitor (BPM) for the CLIC Drive Beam and its associated readout electronics has been successfully tested in the CLIC Test Facility linac (CTF3) at CERN. In addition, a modified prototype with downstream terminated striplines is under development to improve the suppression of unwanted RF signal interference. This paper presents the results of the beam tests, and the most relevant aspects for the modified stripline BPM design and its expected improvements.

  20. High power laser beam delivery monitoring for laser safety

    Science.gov (United States)

    Corder, D. A.; Evans, D. R.; Tyrer, J. R.; Freeland, C. M.; Myler, J. K.

    1997-07-01

    The output of high power lasers used for material processing presents extreme radiation hazards. In normal operation this hazard is removed by the use of local shielding to prevent accidental exposure and system design to ensure efficient coupling of radiation into the workpiece. Faults in laser beam delivery or utilization can give rise to hazardous levels of laser radiation. A passive hazard control strategy requires that the laser system be enclosed such that the full laser power cannot burn through the housing under fault conditions. Usually this approach is too restrictive. Instead, active control strategies can be used in which a fault condition is detected and the laser cut off. This reduces the requirements for protective housing. In this work a distinction is drawn between reactive and proactive strategies. Reactive strategies rely on detecting the effects of an errant laser beam, whereas proactive strategies can anticipate as well as detect fault conditions. This can avoid the need for a hazardous situation to exist. A proactive strategy in which the laser beam is sampled at the final turning mirror is described in this work. Two control systems have been demonstrated; the first checks that beam power is within preset limits, the second monitors incoming beam power and position, and the radiation reflected back from the cutting head. In addition to their safety functions the accurate monitoring of power provides an additional benefit to the laser user.

  1. Field Evaluation of Cereal Combine Harvesters Processing Losses on JD-955 and JD-1165 Combines Equipped with Grain Loss Monitor

    Directory of Open Access Journals (Sweden)

    M.R Mostofi Sarkari

    2016-04-01

    Full Text Available Grain loss monitors are installed on combine harvester and make it possible to measure grain loss on different parts of the combine. The instrument permits the operator to adjust a proper ground speed to keep grain loss within an acceptable range. In this study a loss monitoring system was implemented to measure grain losses continuously on straw walker and sieves. Two grain loss monitors (KEE and TeeJet were installed behind the straw walker and the sieves of JD-955 and JD-1165 combine harvesters. Harvesting performance parameters such as combine total and processing losses were then measured. To evaluate the precision and accuracy of the instruments, the measured and monitored losses were compared and investigated. The results of a two-year research showed that the average processing loss of the combine harvesters with 10-12% grain moisture content and 750 rpm drum speed was 0.82% which is whitin the acceptable range recommended by ASAE Standard No. S343.3. Furthermore, there was no significant difference between the measured and monitored values of processing loss.

  2. Electronics and Calibration system for the CMS Beam Halo Monitor

    CERN Document Server

    Tosi, Nicolo

    2014-01-01

    In the context of increasing luminosity of LHC, it will be important to accurately measure the Machine Induced Background. A new monitoring system will be installed in the CMS cavern for measuring the beam background at high radius. This detector is composed of synthetic quartz Cherenkov radiators, coupled to fast photomultiplier tubes (PMT). The readout chain of this detector will make use of many components developed for the Phase 1 upgrade to the CMS Hadron Calorimeter electronics, with a dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal will be digitized by a charge integrating ASIC (QIE10), providing both the signal rise time and the charge integrated over one bunch crossing.The backend electronics will record bunch-by-bunch histograms, which will be published to CMS and the LHC using the newly designed CMS beam instrumentation specific DAQ. A calibration monitoring system has been designed to generate triggered pulses of light to monitor the efficiency of the sys...

  3. Beam position dependence of a wall-current monitor

    International Nuclear Information System (INIS)

    It was pointed out recently that there exists an appreciable beam position dependence in the wall-current monitor widely used in electron accelerators. Detailed study of this dependence is performed on a test bench varying the pulse width and the frequency of the input signal simulating the beam. The results of experiments show that when the pulse width becomes shorter more appreciable becomes the dependence, and it approaches to that of calculated from the method of images. A unified analysis is under way. (author)

  4. Linear coupling, loss and gain of counterpropagating beams

    Czech Academy of Sciences Publication Activity Database

    Peřinová, V.; Lukš, A.; Křepelka, Jaromír

    2006-01-01

    Roč. 39, č. 9 (2006), s. 2267-2284. ISSN 0953-4075 R&D Projects: GA MŠk(CZ) OC P11.003 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z10100520 Keywords : linear coupling * counterpropagating beams Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.024, year: 2006

  5. Electron beam guiding by grooved SiO2 parallel plates without energy loss

    International Nuclear Information System (INIS)

    Using a pair of grooved SiO2 parallel plates, stably guided electron beams were obtained without energy loss at 800–2000 eV. This shows that the transmitted electrons are guided by a self-organized repulsive electric field, paving the way for a self-adaptive manipulation of electron beams

  6. Electron beam guiding by grooved SiO2 parallel plates without energy loss

    Science.gov (United States)

    Xue, Yingli; Yu, Deyang; Liu, Junliang; Zhang, Mingwu; Yang, Bian; Zhang, Yuezhao; Cai, Xiaohong

    2015-12-01

    Using a pair of grooved SiO2 parallel plates, stably guided electron beams were obtained without energy loss at 800-2000 eV. This shows that the transmitted electrons are guided by a self-organized repulsive electric field, paving the way for a self-adaptive manipulation of electron beams.

  7. Silicon detectors for the n-TOF neutron beams monitoring

    CERN Document Server

    Cosentino, L; Barbagallo, M; Colonna, N; Damone, L; Pappalardo, A; Piscopo, M; Finocchiaro, P

    2015-01-01

    During 2014 the second experimental area EAR2 was completed at the n-TOF neutron beam facility at CERN. As the neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target, the resulting neutron beam covers an enormous energy range, from thermal to several GeV. In this paper we describe two beam diagnostic devices, designed and built at INFN-LNS, both exploiting silicon detectors coupled with neutron converter foils containing 6Li. The first one is based on four silicon pads and allows to monitor the neutron beam flux as a function of the neutron energy. The second one, based on position sensitive silicon detectors, is intended for the reconstruction of the beam profile, again as a function of the neutron energy. Several electronic setups have been explored in order to overcome the issues related to the gamma flash, namely a huge pulse present at the start of each neutron bunch which may blind the detectors for some time. The two devices have been ch...

  8. Performance of MACACO Compton telescope for ion-beam therapy monitoring : first test with proton beams

    NARCIS (Netherlands)

    Solevi, Paola; Munoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosa, Gabriela

    2016-01-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector

  9. Optical Beam Timing Monitor Experiments at the Advanced Light Source

    International Nuclear Information System (INIS)

    We present the initial results of an experimental study of a beam timing monitor based on an optoelectronic technique. This technique uses the electrical signal from a beam position monitor to modulate the amplitude of a train of laser pulses, converting timing jitter into an amplitude jitter. This modulation is then measured with a photodetector and sampled by a fast ADC. This approach has already demonstrated sub-100fs resolution and promises even better results. Additionally, we are planning to use the technique as a way to extract the maximum possible bandwidth from a BPM, avoiding the dispersion typical of long RF cables. We show our initial results using signals from the Advanced Light Source storage ring

  10. The ATLAS Diamond Beam Monitor : Luminosity Detector on the LHC

    CERN Document Server

    Schaefer, Douglas; The ATLAS collaboration

    2015-01-01

    After the first three years of the LHC running the ATLAS experiment extracted it's pixel detector system to refurbish and re-position the optical readout drivers and install a new barrel layer of pixels. The experiment has also taken advantage of this access to also install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes were assembled based on chemical vapour deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This talk will describe the lessons learned in construction and commissioning of the ATLAS x Diamond Beam Monitor (DBM). We will show results from the construction quality assurance tests, commissioning performance, including results from cosmic ray running in early 2015 and also expected first results from LHC run 2 collisions.

  11. The ATLAS Diamond Beam Monitor: Luminosity detector at the LHC

    Science.gov (United States)

    Schaefer, D. M.

    2016-07-01

    After the first three years of the LHC running, the ATLAS experiment extracted its pixel detector system to refurbish and re-position the optical readout drivers and install a new barrel layer of pixels. The experiment has also taken advantage of this access to install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes are based on chemical vapor deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This paper describes the lessons learned in construction and commissioning of the ATLAS Diamond Beam Monitor (DBM). We show results from the construction quality assurance tests and commissioning performance, including results from cosmic ray running in early 2015.

  12. Neutron beam monitor based on a boron-coated GEM

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian-Rong; LI Yi; SUN Zhi-Jia; LIU Ben; WANG Yan-Feng; YANG Gui-An; ZHOU Liang; XU Hong; DONG Jing; YANG Lei

    2011-01-01

    A new thermal neutron beam monitor with a Gas Electron Multiplier (GEM) is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm GEM foils. Enriched boron-10 is coated on one surface of the aluminum cathode plate as the neutron convertor. 96 channel pads with an area of 8 mm×8 mm each are used for fast signal readout.In order to study the basic characteristics of a boron-coated GEM, several irradiation tests were carried out with α source 239pu and neutron source 241Am(Be). The signal induced by the neutron source has a high signal-to-noise ratio. A clear image obtained from α source 239pu is presented, which shows that the neutron beam monitor based on a boron-coated GEM has a good two-dimensional imaging ability.

  13. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  14. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC,

    2007-06-08

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  15. Extracting source parameters from beam monitors on a chopper spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Abernathy, Douglas L [ORNL; Niedziela, Jennifer L [ORNL; Stone, Matthew B [ORNL

    2015-01-01

    The intensity distributions of beam monitors in direct-geometry time-of-flight neutron spectrometers provide important information about the instrument resolution. For short-pulse spallation neutron sources in particular, the asymmetry of the source pulse may be extracted and compared to Monte Carlo source simulations. An explicit formula using a Gaussian-convolved Ikeda-Carpenter distribution is given and compared to data from the ARCS instrument at the Spallation Neutron Source.

  16. Profile Monitors for Wide Multiplicity Range Electron Beams

    CERN Document Server

    Buonomo, B; Quintieri, L

    2005-01-01

    The DAFNE Beam Test Facility (BTF) provides electron and positron beams in a wide range of intensity, from single particle up to 1010 particles per pulse, and energy, from a few tens of MeV up to 800 MeV. The pulse time width can be adjusted between 1 and 10 ns and the maximum repetition rate is 50 Hz. The large range of operation of the facility requires the implementation of different beam profile and multiplicity monitors. In the single particle operation mode the beam spot profile and position are measured by a x-y scintillating fiber system with millimetric resolution and multi-anode PMT readout. From a few tens up to 106-107 particles per pulse, a silicon chamber made of two 9.5x9.5 cm2 wide 400μm thick silicon strip detectors organized in a x-y configuration with a pitch of 121μm has been developed. Once calibrated, the system can be used also as an intensity monitor. The description of the devices and the results obtained during the data taking periods of several experiments at the...

  17. Performance of a reentrant cavity beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Simon, C.; Luong, M.; Chel, S.; Napoly, O.; Novo, J.; Roudier, D. [CEA Saclay, DSM, Irfu, SACM, F-91191 Gif Sur Yvette, (France); Rouviere, N. [CNRS, IN2P3-IPN, F-91406 Orsay, (France); Baboi, N.; Mildner, N.; Nolle, D. [DESY, D-22603 Hamburg, (Germany)

    2008-07-01

    The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryo-module, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10 {mu}m and has the possibility to perform bunch to bunch measurements for the X-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryo-module. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4 {mu}m over a dynamic range {+-} 5 mm in single bunch. (authors)

  18. A beam position monitor system for electron cooler in HIRFL-CSR

    International Nuclear Information System (INIS)

    The efficient electron cooling requires that the ion beam and electron beam are parallel and overlapped. In order to measure the positions of ion beam and electron beam simultaneously, a beam position monitor system is developed for the HIRFL-CSR electron cooler device, which probe consists of four capacitive cylinder linear-cut poles. One can get the both beam positions from the picking up signals of four poles by using Fourier transform (FFT) method. The measurement results show that the beam position monitor system is accurate. This system is suitable for investigating the relation between electron cooling processing and the angle of ion beam and electron beam. (authors)

  19. First Experiences of Beam Presence Detection Based on Dedicated Beam Position Monitors

    CERN Document Server

    Jalal, A; Gasior, M; Todd, B

    2011-01-01

    High intensity particle beam injection into the LHC is only permitted when a low intensity pilot beam is already circulating in the LHC. This requirement addresses some of the risks associated with high intensity injection, and is enforced by a so-called Beam Presence Flag (BPF) system which is part of the interlock chain between the LHC and its injector complex. For the 2010 LHC run, the detection of the presence of this pilot beam was implemented using the LHC Fast Beam Current Transformer (FBCT) system. However, the primary function of the FBCTs, that is reliable measurement of beam currents, did not allow the BPF system to satisfy all quality requirements of the LHC Machine Protection System (MPS). Safety requirements associated with high intensity injections triggered the development of a dedicated system, based on Beam Position Monitors (BPM). This system was meant to work first in parallel with the FBCT BPF system and eventually replace it. At the end of 2010 and in 2011, this new BP...

  20. Off-momentum loss maps with one beam

    CERN Document Server

    Garcia Morales, Hector; Salvachua Ferrando, Belen Maria; CERN. Geneva. ATS Department

    2016-01-01

    The aim of this MD is the benchmarking of simulation of off-momentum loss maps. This will help us to further understand the dynamics of the off-momentum collimation cleaning and give input to the determination of the operational settings of the off-momentum cleaning insertion. The MD was carried out during different end-of-fills of other MDs. In this note we summarize the procedures and the measurements taken during the MD week.

  1. LHC magnet quench test with beam loss generated by wire scan

    CERN Document Server

    Sapinski, M; Dahlerup-Petersen, K; Dehning, B; Emery, j; Ferrari, A; Guerrero, A; Holzer, E B; Koujili, M; Lechner, A; Nebot, E; Scheubel, M; Steckert, J; Verweij, A; Wenninger, J

    2011-01-01

    Beam losses with millisecond duration have been observed in the LHC in 2010 and 2011. They are thought to be provoked by dust particles falling into the beam. These losses could compromise the LHC availability if they provoke quenches of superconducting magnets. In order to investigate the quench limits for this loss mechanism, a quench test using a wire scanner has been performed, with the wire movement through the beam mimicking a loss with similar spatial and temporal distribution as in the case of dust particles. This paper will show the conclusions reached for millisecond-duration dust-provoked quench limits. It will include details on the maximum energy deposited in the coil as estimated using FLUKA code, showing a reasonable agreement with quench limit estimated from the heat transfer code QP3. In addition, information on the damage limit for carbon wires in proton beamswill be presented, following electronmicroscope analysis which revealed strong wire sublimation.

  2. Observations of beam ion losses in TFTR during TAE modes and other MHD activity

    International Nuclear Information System (INIS)

    Direct measurements of fast NBI ion losses have been made near the outer midplane during MHD activity in TFTR. Bursts of beam ion loss are seen coincident with the TAE mode activity. Particles lost during TAE activity are lost at the full injection energy of 100 keV, and only the total efflux of fast ions changes during the mode, not the pitch angle or energy of the lost ions. Reductions in neutron source strength indicate that ∼10 percent of the beam ions can be lost in a single burst, with a cumulative loss of as much as 50 percent. Other MHD activity can cause large losses of beam ions, including passing ions

  3. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Science.gov (United States)

    Tan, Y.-R. E.; Wang, D.; Van Garderen, E.; McKinlay, J.

    2012-10-01

    To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM) has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR) of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre) of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal) and 75 um (vertical).

  4. Cavity Beam Position Monitor System for ATF2

    Energy Technology Data Exchange (ETDEWEB)

    Boogert, Stewart; /Oxford U., JAI; Boorman, Gary; /Oxford U., JAI; Swinson, Christina; /Oxford U., JAI; Ainsworth, Robert; /Royal Holloway, U. of London; Molloy, Stephen; /Royal Holloway, U. of London; Aryshev, Alexander; /KEK, Tsukuba; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; Urakawa, Junji; /KEK, Tsukuba; Frisch, Josef; /SLAC; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Nelson, Janice; /SLAC; Smith, Tonee; /SLAC; White, Glen; /SLAC; Woodley, Mark; /SLAC; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Kim, Hyoung-Suk; /Kyungpook Natl. U.; Kim, Youngim; /Kyungpook Natl. U. /University Coll. London /Kyungpook Natl. U. /Fermilab /Pohang Accelerator Lab.

    2012-07-09

    The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (CBPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance. The ATF2 C-band system is performing well, with individual CBPM resolution approaching or at the design resolution of 50 nm. The changes in the CBPM calibration observed over three weeks can probably be attributed to thermal effects on the mixer electronics systems. The CW calibration tone power will be upgraded to monitor changes in the electronics gain and phase. The four S-band CBPMs are still to be investigated, the main problem associated with these cavities is a large cross coupling between the x and y ports. This combined with the large design dispersion in that degion makes the digital signal processing difficult, although various techniques exist to determine the cavity parameters and use these coupled signals for beam position determination.

  5. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Directory of Open Access Journals (Sweden)

    McKinlay J.

    2012-10-01

    Full Text Available To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal and 75 um (vertical.

  6. Beam position monitor system of J-PARC RCS

    International Nuclear Information System (INIS)

    The J-PARC RCS is a 25 Hz Rapid-Cycling proton Synchrotron and its designed beam power is 1 MW. The beam position monitor (BPM) system at J-PARC RCS is described in this paper. The pre-defined diameter of the BPM detectors is larger than 250 mm, however, the system has to measure the beam position very accurately. In addition, it is necessary to have a large dynamic range. The system should work not only for the high intensity but also for low intensity, such as during beam commissioning, when the intensity is below 1% of the design intensity. There are 54 BPM detectors around the ring and most of them are placed inside steering magnets because of quite limited space. The BPM detector is an electro-static type and it has four electrodes, and a pair of electrodes gives a good linear response with a diagonal cut shape to detect the charge center precisely. The signal processing units, which are equipped with 14-bit 40 MS/s ADC and 600 MHz DSP, have been developed. They are accessed via shared memory space and controlled by EPICS. Such a processing unit is capable of recording the full 25 Hz pulse data for the so-called “COD mode” (averaged beam position calculation) and it can also store the whole waveform data for further analysis, like turn-by-turn position calculation. The resolution was estimated to be 20μm for “COD mode” and to be 0.3 mm for the turn-by-turn mode with relatively low intensity of 8×1011ppp. The position accuracy is estimated to be about 0.5 mm using a newly developed Beam Based Alignment (BBA) method.

  7. On the online monitor for longitudinal beam profile measurements at FLASH

    International Nuclear Information System (INIS)

    The Free-Electron Laser in Hamburg (FLASH) is equipped with a tranverse deflecting structure (TDS) for longitudinal beam profile measurements. As FLASH is a multi-bunch machine, an online monitor for these measurements would facilitate the analysis of single bunches within the bunch train. The setup of the TDS as an online monitor requires to apply a special accelerator optics inside its section. Phase advances and beta-functions need to be set in order to allow an effective kicking of a single bunch to the diagnosis screen, as well as to allow an adequate time resolution for the beam profile measurements. Furthermore a matching into the adjacent undulator section is crucial. Simulations have been performed using MAD to optimise the optics for this application. A bunch which is kicked for the measurement, will hit a copper absorber and cause electromagnetic cascade showers. These showers have been observed to be a threat to the machine protection system, as they cause alarms at beam loss monitors, which are distributed along the undulators. Simulations have been performed in order to study the benefit of additional shielding.

  8. Capacitive beam position monitors for the low-β beam of the Chinese ADS proton linac

    Science.gov (United States)

    Zhang, Yong; Wu, Jun-Xia; Zhu, Guang-Yu; Jia, Huan; Xue, Zong-Heng; Zheng, Hai; Xie, Hong-Ming; Kang, Xin-Cai; He, Yuan; Li, Lin; Denard, Jean Claude

    2016-02-01

    Beam Position Monitors (BPMs) for the low-β beam of the Chinese Accelerator Driven Subcritical system (CADS) Proton linac are of the capacitive pick-up type. They provide higher output signals than that of the inductive type. This paper will describe the design and tests of the capacitive BPM system for the low-β proton linac, including the pick-ups, the test bench and the read-out electronics. The tests done with an actual proton beam show a good agreement between the measurements and the simulations in the time domain. Supported by National Natural Science Foundation of China (11405240) and “Western Light” Talents Training Program of Chinese Academy of Sciences

  9. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    CERN Document Server

    Povoli, Marco; Bravin, Alberto; Cornelius, Iwan; Bräuer-Krisch, Elke; Fournier, Pauline; Hansen, Thor-Erik; Kok, Angela; Lerch, Michael; Monakhov, Edouard; Morse, John; Petasecca, Marco; Requardt, Herwig; Rosenfeld, Anatoly; Röhrich, Dieter; Sandaker, Heidi; Salomé, Murielle; Stugu, Bjarne

    2015-01-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any...

  10. Condition monitoring for a neutral beam injector cryopumping system

    Energy Technology Data Exchange (ETDEWEB)

    Wright, N., E-mail: n.wright@lboro.ac.uk [School of Electronic and Electrical Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Dixon, R., E-mail: r.dixon@lboro.ac.uk [School of Electronic and Electrical Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Verhoeven, R., E-mail: roel.verhoeven@ccfe.ac.uk [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► The development of a cryopumping condition monitoring scheme is presented. ► A residual generation scheme is used to detect two faults. ► Kalman filtering is used to generate the residuals. ► A filtering and voting arrangement is used to evaluate the residuals. ► A non-linear simulation model is used to verify the scheme. -- Abstract: For neutral beam injection systems, the maintenance of a vacuum inside the injector box is essential for normal operation. Cryogenic pumping systems are often used to create and maintain this vacuum. Cryogenic pumping systems have been deployed on the neutral beam heating systems supporting the Joint European Torus. With these as a target application, the development of a condition monitoring scheme is presented. The scheme uses a residual generation approach. A bank of Kalman filters is used to estimate measured process variables. A residual evaluator is used to map residual signals onto a set of faults. Two example faults are simulated to demonstrate the response of the scheme. This paper contributes to the wider fusion development programme by demonstrating how a contemporary condition monitoring technique can be applied to a fusion support system, in order to improve its availability.

  11. Simulation of ion beam losses in LHC magnets

    CERN Document Server

    Bruce, R; Jowett, John M; Riklund, R

    2005-01-01

    At the particle physics laboratory CERN, the largest accelerator ever, the Large Hadron Collider (LHC), is under construction. In the LHC ultra relativistic particles, mainly protons but also lead ions, will be brought into collision. One problem that arises in the operation is that colliding ion beams in the machine have a very large cross section for electromagnetic interactions, in particular Bound Free Pair Production (BFPP). An electron-positron pair is created by the electromagnetic field between two colliding particles and the electron is created in a bound state of one of the ions. Because of this reaction the ion changes its charge and therefore leaves the wanted trajectory and crashes in a superconducting magnet, depositing heat. The impact of the wrongly charged ions on the inside of the vacuum pipe was simulated with the simulation program FLUKA. It was concluded that it is not likely that enough heat is deposited in the coils of the superconducting magnet to induce a quench, although some uncerta...

  12. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    Science.gov (United States)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3–5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  13. Summary of the 2014 Beam-Halo Monitoring Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Alan

    2015-09-25

    Understanding and controlling beam halo is important for high-intensity hadron accelerators, for high-brightness electron linacs, and for low-emittance light sources. This can only be achieved by developing suitable diagnostics. The main challenge faced by such instrumentation is the high dynamic range needed to observe the halo in the presence of an intense core. In addition, measurements must often be made non-invasively. This talk summarizes the one-day workshop on Beam-Halo Monitoring that was held at SLAC on September 19 last year, immediately following IBIC 2014 in Monterey. Workshop presentations described invasive techniques using wires, screens, or crystal collimators, and non-invasive measurements with gas or scattered electrons. Talks on optical methods showed the close links between observing halo and astronomical problems like observing the solar corona or directly observing a planet orbiting another star.

  14. Tritium Monitoring in the ITER Neutral Beam Test Facility

    International Nuclear Information System (INIS)

    The proposed ITER Neutral Beam Test Facility (NBTF) is designed to operate with negative ion neutral injectors in order to provide the required beam power and efficiency. The operation of the neutral beam test bed involves the firing of a beam of deuterons into a calorimeter. The deuterons will become embedded in the calorimeter and subsequent particles can be involved in deuterium fusion reactions. There are two branches of this reaction which have approximately equal probability. These are: D + D → 3He + n D + D → 3H + p Because of this relationship, it is possible to estimate the level of tritium production accurately by measuring the neutron production. The proposed testing campaign will generate an annual tritium discharge to the atmosphere of about 246 GBq. An absolutely calibrated neutron monitor is needed for tritium accounting but difficulties arise because the neutron source is complex: it is spatially extended and varying and is anisotropic. Furthermore the material of the injector will cause significant scattering of neutrons between the source and any detector. To resolve these problems it is proposed that a set of detectors is deployed around the injector and that a neutron source be placed within the injector is used to calibrate them. Very detailed Monte-Carlo calculations have been carried out to model the neutron transport thought the NBTF. All major component of the injector have been modelled. These include the calorimeter, the residual ion dump, the neutraliser, the beam source, the HV bushing and the vacuum vessel. The spatial variation of the neutron source, based on the deuteron deposition on the calorimeter and the residual ion dump has been simulated. The effects of anisotropy and the angular dependence of the neutron energy spectrum have been included. The calculations demonstrate that such a suite of detectors can be calibrated using a 252Cf source to absolutely determine the neutron and therefore the tritium production to an

  15. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    Science.gov (United States)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82+208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  16. Numerical simulation of the PEP-II beam position monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, N.; Martin, D.; Ng, C.-K.; Smith, S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Weiland, T.

    1996-08-01

    We use MAFIA to analyze the PEP-II button-type beam position monitor (BPM). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM is determined. Thus the issues of signal sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, we find that internal resonant modes are a major source of high value narrow-band impedances. The effects of these resonances on coupled-bunch instabilities are discussed. An estimate of the power dissipation in the ceramic vacuum seal under high current operation is given. (author)

  17. Simulation of PEP-II beam position monitors

    International Nuclear Information System (INIS)

    The authors use MAFIA to analyze the PEP-II button-type beam position monitors (BPMs). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM can be determined. Thus the issues of sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, they find that internal resonant modes are a major source of high value narrow-band impedances. These are evaluated and methods are presented to suppress these parasitic resonances below the tolerable limit of multibunch instabilities

  18. Beam position monitors for SuperKEKB damping ring

    International Nuclear Information System (INIS)

    Design work for the beam position monitor systems for SuperKEKB damping ring has been performed. The longitudinal and transverse impedance and the signal output of the button electrode with diameter of 6 mm were calculated using 3D electro-magnetic simulation of GdfidL. The estimated growth rate of the coupled-bunch instability was much smaller than the radiation damping rate. A turn-by-turn position detector using Log-Ratio method has also been designed and fabricated based on the estimated signal outputs. (author)

  19. Insertion losses of a tilted plano surface in a convergent beam

    International Nuclear Information System (INIS)

    The radiant transmittance of a tilted plano surface in a convergent conical beam of varying intensity depends upon the local angle of incidence and the projection of the plane-polarized flux onto the plane of incidence. For the surface at Brewser's angle and modest cone angles, the insertion loss for a plane-polarized beam can be as large as 10%, negating any advantage of the Brewster's angle window. Details of the calculations are given and examples are shown. 2 figures

  20. Hybrid monitor for both beam position and tilt of pulsed high-current beams

    International Nuclear Information System (INIS)

    A Hybrid beam monitor, integrated with both azimuthal and axial B-dot probes, was designed for simultaneous measurement of both beam position and beam angle for pulsed high-current beams at the same location in beam pipe. The output signals of axial B-dot probes were found to be mixed with signals caused by transverse position deviation. In order to eliminate the unwanted signals, an elimination method was developed and its feasibility tested on a 50-Ω coaxial line test stand. By this method, a waveform, shape-like to that of input current and proportional to the tilt angle, was simulated and processed by following integration step to achieve the tilt angle. The tests showed that the measurement error of displacement and tilt angle less than 0.3 mm and 1.5 mrad, respectively. The latter error could be reduced with improved probes by reducing the inductance of the axial B-dot probe, but the improvement reached a limit due to some unknown systemic mechanism

  1. Beam position monitor R&D for keV ion beams

    CERN Document Server

    Naveed, S; Nosych, A; Søby,L

    2013-01-01

    Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring (BPM) system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams with a focus on the ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably.

  2. Development of non-contact beam intensity monitor by residual gas ionization

    International Nuclear Information System (INIS)

    Non-contact beam intensity monitor is an important device for high-intensity proton accelerator, such as J-PARC. Especially, it is difficult to measure beam intensity of DC-like beam with off-contact. We have developed non-contact beam intensity monitor for J-PARC slow-extraction beam line by measuring charge of ionization electrons in 1 Pa residual gas. In this article, specifications of the residual gas ionization current monitor (RGICM) and results of a test experiment with 65 MeV proton beam at Research Center for Nuclear Physics in Osaka University are reported. (author)

  3. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    CERN Document Server

    Bruce, R; Boccone, V; Bracco, C; Brugger, M; Cauchi, M; Cerutti, F; Deboy, D; Ferrari, A; Lari, L; Marsili, A; Mereghetti, A; Mirarchi, D; Quaranta, E; Redaelli, S; Robert-Demolaize, G; Rossi, A; Salvachua, B; Skordis, E; Tambasco, C; Valentino, G; Weiler, T; Vlachoudis, V; Wollmann, D

    2014-01-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

  4. Beam loss studies on silicon strip detector modules for the CMS experiment

    CERN Document Server

    Fahrer, Manuel

    2006-01-01

    The large beam energy of the LHC demands for a save beam abort system. Nevertheless, failures cannot be excluded with last assurance and are predicted to occur once per year. As the CMS experiment is placed in the neighboured LHC octant, it is affected by such events. The effect of an unsynchronized beam abort on the silicon strip modules of the CMS tracking detector has been investigated in this thesis by performing one accelerator and two lab experiments. The dynamical behaviour of operational parameters of modules and components has been recorded during simulated beam loss events to be able to disentangle the reasons of possible damages. The first study with high intensive proton bunches at the CERN PS ensured the robustness of the module design against beam losses. A further lab experiment with pulsed IR LEDs clarified the physical and electrical processes during such events. The silicon strip sensors on a module are protected against beam losses by a part of the module design that originally has not been...

  5. Simulation of Heavy-Ion Beam Losses with the SixTrack-FLUKA Active Coupling

    CERN Document Server

    Hermes, Pascal; Cerutti, Francesco; Ferrari, Alfredo; Jowett, John; Lechner, Anton; Mereghetti, Alessio; Mirarchi, Daniele; Ortega, Pablo; Redaelli, Stefano; Salvachua, Belen; Skordis, Eleftherios; Valentino, Gianluca; Vlachoudis, Vasilis

    2016-01-01

    The LHC heavy-ion program aims to further increase the stored ion beam energy, putting high demands on the LHC collimation system. Accurate simulations of the ion collimation efficiency are crucial to validate the feasibility of new proposed configurations and beam parameters. In this paper we present a generalized framework of the SixTrack-FLUKA coupling to simulate the fragmentation of heavy-ions in the collimators and their motion in the LHC lattice. We compare heavy-ion loss maps simulated on the basis of this framework with the loss distributions measured during heavy-ion operation in 2011 and 2015.

  6. Control and monitoring system for internal beam diagnostics facility of SCC

    International Nuclear Information System (INIS)

    The first Ion beam will be accelerated in K-500 Superconducting Cyclotron at VECC soon. The acceleration zone employs Main probe and Beam viewer probe for internal beam diagnostics. The ion beam, during acceleration inside the cyclotron, is needed to be maintained in median plane. The deviation of beam at various radial positions is to be monitored by Main-Probe head. The characteristics of beam e.g. size and shape information is required at the time of beam tuning. A Beam Viewer Probe, made of a borescope fitted with a fluorescent plate is used to display the beam characteristics. High resolution probe head driving systems are developed along with VB GUI to control both the drives and monitor the beam properties (e.g. magnitude, deviation, size, shape). This paper describes the control instrumentation and monitoring scheme for main probe and viewer probe. (author)

  7. Simulation study of beam ion loss due to Alfven eigenmode bursts

    International Nuclear Information System (INIS)

    Recurrent bursts of toroidicity-induced Alfven eigenmodes (TAE) are studied using a self-consistent simulation model. Bursts of beam ion losses observed in the neutral beam injection experiment at the Tokamak Fusion Test Reactor [K. L. Wong et al., Phys. Rev. Lett. 66, 1874 (1991)] are reproduced using the experimental parameters. It is found that synchronized TAE bursts take place at regular time intervals of 2.5 ms, which is fairly close to the experimental value of 2.2 ms. The stored beam energy saturates at 10% of that of the classical slowing-down distribution. This is consistent with an important experimental aspect that the beam confinement time is much shorter than the collisional slowing-down time. The stored beam energy drop associated with each burst has a modulation depth of 20% which is comparable to the inferred experimental value of 7%. This is the first simulation that reproduces all of these experimental aspects. The beam ion distribution hovers around a marginal stability state. Test particle analysis demonstrates that the disappearance of KAM surfaces in a coordinate system co-moving with each eigenmode leads to beam ion loss. (author)

  8. Loss of balance during balance beam walking elicits a multifocal theta band electrocortical response

    OpenAIRE

    Sipp, Amy R.; Gwin, Joseph T; Makeig, Scott; Ferris, Daniel P

    2013-01-01

    Determining the neural correlates of loss of balance during walking could lead to improved clinical assessment and treatment for individuals predisposed to falls. We used high-density electroencephalography (EEG) combined with independent component analysis (ICA) to study loss of balance during human walking. We examined 26 healthy young subjects performing heel-to-toe walking on a treadmill-mounted balance beam as well as walking on the treadmill belt (both at 0.22 m/s). ICA identified clust...

  9. Radiation losses in PLT during neutral beam and ICRF heating experiments

    International Nuclear Information System (INIS)

    Radiation and charge exchange losses in the PLT tokamak are compared for discharges with ohmic heating only (OH), and with additional heating by neutral beams (NB) or RF in the ion cyclotron frequency range (ICRF). Spectroscopic, bolometric and soft x-ray diagnostics were used. The effects of discharge cleaning, vacuum wall gettering, and rate of gas inlet on radiation losses from OH plasmas and the correlation between radiation from plasma core and edge temperatures are discussed

  10. GEM-based thermal neutron beam monitors for spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Croci, G., E-mail: Gabriele.Croci@cern.ch [Istituto di Fisica del Plasma “P. Caldirola”—CNR, Milan (Italy); Sez. INFN Milano-Bicocca, Milano (Italy); Claps, G. [Laboratori Nazionali di Frascati—INFN, Frascati (Italy); Caniello, R. [Istituto di Fisica del Plasma “P. Caldirola”—CNR, Milan (Italy); Cazzaniga, C. [Dipartimento di Fisica “G. Occhialini”, University of Milano-Bicocca (Italy); Grosso, G. [Istituto di Fisica del Plasma “P. Caldirola”—CNR, Milan (Italy); Murtas, F. [Laboratori Nazionali di Frascati—INFN, Frascati (Italy); Tardocchi, M.; Vassallo, E. [Istituto di Fisica del Plasma “P. Caldirola”—CNR, Milan (Italy); Gorini, G. [Dipartimento di Fisica “G. Occhialini”, University of Milano-Bicocca (Italy); Sez. INFN Milano-Bicocca, Milano (Italy); Horstmann, C.; Kampmann, R.; Nowak, G.; Stoermer, M. [Institute of Materials Research, Helmholtz-Zentrum Geesthacht (Germany)

    2013-12-21

    The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of {sup 3}He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1μm thick B{sub 4}C layer used to convert thermal neutrons to charged particles through the {sup 10}B(n,{sup 7}Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHM{sub x}=31 mm and FWHM{sub y}=36 mm), bGEM thermal neutron counting efficiency (≈1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to {sup 3}He-based gaseous detectors.

  11. A beam monitor of the 2.5 GeV Bonn Electron Synchrotron

    International Nuclear Information System (INIS)

    In the present work a monitor of the Bonn 2.5 GeV Synchrotron photon beam is described. The monitor consists of a Zn S phosphor layer on a movable copper sheet which allows continuously monitoring the gamma beam position. (FKS)

  12. Results of beam based gain calibration for beam position monitor at J-PARC Main Ring

    International Nuclear Information System (INIS)

    Beam Position Monitor (BPM) is one of the essential elements in a synchrotron facility, obtaining the circulating beam information for stabilization of the closed orbit. The accuracy of beam positions greatly affects the orbit stabilization, however, actual signal strength from a BPM depends on individuality such as 1) signal transmission for a long distance, 2) processing circuit, and 3) contact resistance at the connected parts, etc. These things cause deviations in the gain of the signal response. The gains are different from each other even in one BPM. In order to correct this relative gain deviations between electrodes, a Beam Based Gain Calibration (BBGC) method has been proposed. Development of a new method for adequate gain calibration has been an urgent issue for J-PARC Main Ring. It has been found that an analysis using Total Least Square fitting (TLS) adequately reproduces the BPM gain with sufficient accuracy. The gains obtained from the data are varied in the range of less than ±5%, and the accuracy is within ±0.6%. (author)

  13. Very Fast Losses of the Circulating LHC Beam, their Mitigation and Machine Protection

    CERN Document Server

    Baer, Tobias; Elsen, Eckhard

    The Large Hadron Collider (LHC) has a nominal energy of 362MJ stored in each of its two counter-rotating beams - over two orders of magnitude more than any previous accelerator and enough to melt 880kg of copper. Therefore, in case of abnormal conditions comprehensive machine protection systems extract the beams safely from the LHC within not more than three turns $\\approx$270$\\mu$s. The first years of LHC operation demonstrated a remarkable reliability of the major machine protection systems. However, they also showed that the LHC is vulnerable to losses of the circulating beams on very fast timescales, which are too fast to ensure an active protection. Very fast equipment failures, in particular of normal-conducting dipole magnets and the transverse damper can lead to such beam losses. Whereas these failures were already studied in the past, other unexpected beam loss mechanisms were observed after the LHC start-up: so-called (un)identified falling objects (UFOs), which are believed to be micrometer-sized m...

  14. Multiple-electron losses in uranium ion beams in heavy ion synchrotrons

    Science.gov (United States)

    Bozyk, L.; Chill, F.; Litsarev, M. S.; Tolstikhina, I. Yu.; Shevelko, V. P.

    2016-04-01

    Charge changing processes as the result of collisions with residual gas particles are the main cause of beam loss in high energy medium charge state heavy ion beams. To investigate the magnitude of this effect for heavy ion synchrotrons like the planned SIS100 at GSI, the multiple-electron and the total electron-loss cross sections are calculated for Uq+ ions, q = 10, 28, 40, 73, colliding with typical gas components H2, He, C, N2, O2, and Ar at ion energies E = 1 MeV/u-10 GeV/u. The total electron-capture cross sections for U28+ and U73+ ions interacting with these gases are also calculated. Most of these cross sections are new and presented for the first time. Calculated charge-changing cross sections are used to determine the ion-beam lifetimes τ for U28+ ions which agree well with the recently measured values at SIS18/GSI in the energy range E = 10-200 MeV/u. Using simulations made by the StrahlSim code with the reference ion U28+, it is found that in SIS100 the beam loss caused by single and multiple electron losses has only little impact on the residual gas density due to the high efficiency of the ion catcher system.

  15. Low loss power splitter for antenna beam forming networks using probes in a waveguide

    DEFF Research Database (Denmark)

    Dich, Mikael; Mortensen, Mette Dahl

    1994-01-01

    The design of a low loss one-to-four power splitter suitable for beam forming networks in antenna arrays is presented. The power splitter is constructed of a shorted waveguide in which five coaxial probes are inserted. Methods for the design of the power splitter are presented together with an...

  16. Low loss power splitter for antenna beam forming networks using probes in a waveguide

    OpenAIRE

    Dich, Mikael; Mortensen, Mette Dahl

    1994-01-01

    The design of a low loss one-to-four power splitter suitable for beam forming networks in antenna arrays is presented. The power splitter is constructed of a shorted waveguide in which five coaxial probes are inserted. Methods for the design of the power splitter are presented together with an experimental verification

  17. Flying wire beam profile monitor at the J-PARC MR

    International Nuclear Information System (INIS)

    A flying wire beam profile monitor has been assembled and installed at the main ring of the Japan Proton Accelerator Research Complex. The monitor is to measure the horizontal beam profile using a carbon fiber of 7 μmφ. The fiber crosses the beam with the speed of 10 m/s. Secondary particles from the beam-wire scattering is detected using a scintillation counter. The scintillator signal as a function of the wire position is to be reconstructed as a beam profile. The high scanning speed and the minimum material are necessary for the accurate beam profile measurement. The monitor has been operated in the beam commissioning run of the main ring. The beam profile data have been successfully acquired after the reduction of the beam background. (author)

  18. RESIDUAL GAS IONIZATION BEAM PROFILE MONITOR ON 40MeV H— BEAM TRANSPORT LINE

    Institute of Scientific and Technical Information of China (English)

    徐伟鹏; E.Takasaki

    1995-01-01

    The monitor is composed of a pair of electrodes,a single stage of microchannel plate,a phosphor screen,a CCD camera and a PC computer,To obtain a good uniform collecting field,forming electrodes system is used instead of that with a resistive divider,The readout system is performed by the phosphor screen and the CCD camera because the spatial resolution is not limited by the mechanical structure like the anode strip type and such video display system is very useful for beam studies and operation of the 40MeV linac,Besides,the design and test results are described in detail.

  19. LHCB: A LHCb-VELO module as beam quality monitor for proton therapy beam at the Clatterbridge Centre for Oncology

    CERN Multimedia

    Casse, G; Patel, G D; Smith, N A; Kacperek, A; Marsland, B

    2010-01-01

    The progress in detector technology, driven by the needs of particle tracking and vertexing in the present LHC and its upgrade (sLHC), has led to the design of silicon sensors with low mass, high granularity, high speed and unprecedented radiation hardness. The sensors designed for such a harsh environment can be profitably used for instrumenting the control systems of therapeutic hadron beams. The high granularity and readout clock speed are well suited for monitoring continuous beam currents. The low mass allows reduced interference with the beam whilst monitoring its profile with high precision. The high resolution and sensitivity to minimum ionising particles allows monitoring of the beam spot position by measurement of the halo in real time, without any interference with the beam spot used in therapy.

  20. Trichogram To Monitor Therapeutic Benefit In Hair Loss

    Directory of Open Access Journals (Sweden)

    Uppal Monica

    2004-01-01

    Full Text Available Trichogram is a method of quantifying hair. We report 3 cases of diffuse hair loss of varying etiology in whom the improvement after therapeutic intervention could be objectively documented using trichogram.

  1. Data acquisition and online monitoring software for CBM test beams

    International Nuclear Information System (INIS)

    The Compressed Baryonic Matter (CBM) experiment is intended to run at the FAIR facility that is currently being built at GSI in Darmstadt, Germany. For testing of future CBM detector and read-out electronics prototypes, several test beam campaigns have been performed at different locations, such as GSI, COSY, and CERN PS. The DAQ software has to treat various data inputs: standard VME modules on the MBS system, and different kinds of FPGA boards, read via USB, Ethernet, or optical links. The Data Acquisition Backbone Core framework (DABC) is able to combine such different data sources with event-builder processes running on regular Linux PCs. DABC can also retrieve the instrumental set-up data from EPICS slow control systems and insert it into the event data stream for later analysis. Vice versa, the DIM based DABC control protocol has been integrated to the general CBM EPICS IOC by means of an EPICS-DIM interface. Hence the DAQ can be monitored and steered with a CSS based operator GUI. The CBM online monitoring analysis is based on the GSI Go4 framework which can directly connect to DABC online data via sockets, or process stored data from list-mode files. A Go4 sub-framework has been implemented to provide possibility of parallel development of analysis code for different sub-detectors groups. This allows divide the Go4 components up into independent software packages that can run either standalone, or together at the beam-time in a full set-up.

  2. Simulation of the ATLAS SCT barrel module response to LHC beam loss scenarios

    CERN Document Server

    Rose, P; The ATLAS collaboration; Fadeyev, V; Spencer, E; Wilder, M; Domingo, M

    2014-01-01

    In the event of beam loss at the LHC, ATLAS Inner Detector components nearest the beam line may be subjected to unusually large amounts of radiation. Understanding their behavior in such an event is important in determining whether they would still function properly. We built a SPICE model of the silicon strip module electrical system to determine the behavior of its elements during a realistic beam loss scenario. We found that the power supply and bias filter characteristics strongly affect the module response in such scenarios. In particular, the following self-limiting phenomena were observed: there is a finite amount of charge initially available on the bias filter capacitors for collection by the strips; the power supply current limit reduces the rate at which the bias filter capacitors' charge can be replenished; the reduced bias voltage leads to a smaller depletion depth in the sensors which results in less collected charge. These effects provide a larger measure of safety during beam loss events than ...

  3. Evaluation of Beam Loss and Energy Depositions for a Possible Phase II Design for LHC Collimation

    Energy Technology Data Exchange (ETDEWEB)

    Lari, L.; /EPFL-ISIC, Lausanne /CERN; Assmann, R.; /CERN; Bracco, C.; /EPFL-ISIC, Lausanne /CERN; Brugger, M.; /CERN; Cerutti, F.; /CERN; Doyle, E.; /SLAC; Ferrari, A.; /CERN; Keller, L.; Lundgren, S.; Markiewicz, Thomas W.; /SLAC; Mauri, M.; Redaelli, S.; Sarchiapone, L.; /CERN; Smith, J.; /SLAC; Vlachoudis, V.; Weiler, T.; /CERN

    2011-11-07

    The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  4. Evaluation of Beam Losses And Energy Deposition for a Possible Phase II Design for LHC Collimation

    Energy Technology Data Exchange (ETDEWEB)

    Lari, L.; Assmann, R.W.; Bracco, C.; Brugger, M.; Cerutti, F.; Ferrari, A.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Vlachoudis, Vasilis; Weiler, Th.; /CERN; Doyle, J.E.; Keller, L.; Lundgren, S.A.; Markiewicz, Thomas W.; Smith, J.C.; /SLAC; Lari, L.; /LPHE, Lausanne

    2011-11-01

    The Large Hadron Collider (LHC) beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  5. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    International Nuclear Information System (INIS)

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper

  6. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    Science.gov (United States)

    Povoli, M.; Alagoz, E.; Bravin, A.; Cornelius, I.; Bräuer-Krisch, E.; Fournier, P.; Hansen, T. E.; Kok, A.; Lerch, M.; Monakhov, E.; Morse, J.; Petasecca, M.; Requardt, H.; Rosenfeld, A. B.; Röhrich, D.; Sandaker, H.; Salomé, M.; Stugu, B.

    2015-11-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

  7. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Directory of Open Access Journals (Sweden)

    Shimozuma T.

    2015-01-01

    Full Text Available In a high power Electron Cyclotron Resonance Heating (ECRH system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  8. Minimizing energy losses in plasma-filled waveguide using relativistic electron beam

    International Nuclear Information System (INIS)

    In this work we investigate the effect of a relativistic electron beam on the field stability and minimize the energy losses in waveguide. Analytical calculations are performed to find the plasma dielectric tensor, which leads to apply the boundary conditions at plasma-conductor interface. In addition we derive the dispersion equations which describe E- and H-waves, hence the damping rate of these waves. The necessary condition for the field stability in the waveguide and amplification coefficient for E-wave is also obtained. The effect of external magnetic field is taken into consideration. Electron beam is found to play a crucial role in controlling the field attenuation in waveguide. (author)

  9. Insertion losses of a tilted plano surface in a convergent beam

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.F.; Baumeister, P.

    1983-01-01

    The radiant transmittance of a tilted plano surface in a convergent conical beam of varying intensity depends upon the local angle of incidence and the projection of the plane-polarized flux onto the plane of incidence. For the surface at Brewser's angle and modest cone angles, the insertion loss for a plane-polarized beam can be as large as 10%, negating any advantage of the Brewster's angle window. Details of the calculations are given and examples are shown. 2 figures.

  10. Polarisation splitting of laser beams by large angles with minimal reflection losses

    International Nuclear Information System (INIS)

    New crystal anisotropic prisms for splitting orthogonally polarised components of laser radiation by large angles with minimal reflection losses caused by the Brewster refraction and total internal reflection of polarised waves from the crystal-air interface are considered and the method for their calculation is described. It is shown that, by assembling glue-free combinations of two or three prisms, thermally stable beamsplitters can be fabricated, which are free from the beam astigmatism and the wave dispersion of the output angles of the beams. The parameters and properties of new beamsplitters are presented in a convenient form in figures and tables. (laser applications and other topics in quantum electronics)

  11. Beam loss in HIRFL-CSR due to collisions with residual gas in vacuum

    International Nuclear Information System (INIS)

    The author discusses the collision of heavy ions with residual gas atoms in the vacuum and the cross-sections of the collision processes. The method calculating beam transmission efficiency in vacuum is presented taking HIRFL and CSR machine as examples. Based on rich experimental data, a series of empirical formulae of calculating the cross-section of charge changing process is given. The transmission efficiency curves of different sections in HIRFL and CSR are also calculated, and thus the reasonable requirements for HIRFL and CSR vacuum systems are given. The calculation method has been checked by the measurements of vacuum and beam loss in HIRFL

  12. Background gas density and beam losses in NIO1 beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Veltri, P.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, v.le dell’Università 2, I-35020 Legnaro (PD) (Italy)

    2016-02-15

    NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

  13. Background gas density and beam losses in NIO1 beam source

    Science.gov (United States)

    Sartori, E.; Veltri, P.; Cavenago, M.; Serianni, G.

    2016-02-01

    NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

  14. A two-dimensional beam profile monitor with high dynamic-range using multi-screen for intense proton beams

    International Nuclear Information System (INIS)

    An instrument for beam shape measurement including the halo is strongly required in intense proton accelerators such as the J-PARC. For diagnosing of the beam halo and halo cut at the injection beam line (3-50 BT) which connects the rapid cycling synchrotron (RCS) and the main ring (MR) in the J-PARC, we have developed a high sensitive two-dimensional profile monitor with screens. The beam core was observed with OTR from titanium foil screen, and the beam halo whose density were less almost three orders than it of the beam core was observed with fluorescence (FL) from chromium doped alumina screens placed in the four directions around the beam space. These alumina screens and remote movable system were installed in this spring, and they can be used with existing OTR screens simultaneously. These OTR and FL are focused in the same optical system having large opening angle of 30 degree, and these are observed by a camera with an image intensifier (II). By these method, two-dimensional beam profile contained the beam halo of high-intensity proton beam of 1.5 × 1013 was measured successfully with a dynamic range of more than six orders in magnitude. Two typical measured results as below are discussed mainly in this paper: (1) halo cut by the beam collimators, (2) simultaneous measurement of the beam halo of the minus 4th order with the beam core. These high-sensitive two-dimensional data give powerful information for beam diagnosing. As further topics, increasing the sensitivity of the beam halo measurement and simultaneous measurement of beam halo with beam core with wider dynamic range, their studies are planned this autumn, are also described. (author)

  15. Energy loss mechanism of a gold ion beam on a tandem acceleration system

    International Nuclear Information System (INIS)

    Heavy ion beam probe (HIBP) is used as a reliable method to measure plasma potential and its fluctuation in magnetically confined fusion plasma. The origins of the energy spread on a tandem accelerator system are the fluctuation of acceleration voltage, the energy spread of negative ions produced in an ion source, and the energy broadening caused in a charge stripping gas cell. In the present work, the experimental and theoretical studies mainly on the second and third problems were carried out. A tandem acceleration test stand was constructed, which consists of a negative gold ion source, a tandem acceleration system, a movable Faraday cup and an energy analyzer. The energy spectra of the Au- beam extracted from the ion source were measured. The energy shift between the primary negative ion beam and the positive ion beam converted in a gas cell at small gas thickness was measured. The energy loss spectra and the energy broadening of Au+ beam are explained. A simple model is proposed by using the semi-classical internal energy transfer function of Firsov and the scattering by the unified potential of Ziegler. The energy broadening of Au+ beam produced by a tandem system can be estimated by the present theoretical prediction. (K.I.)

  16. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    Science.gov (United States)

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. PMID:26595774

  17. Development of a highly sensitive beam current monitor with a SQUID and superconducting magnetic shield

    International Nuclear Information System (INIS)

    Beam diagnostics are an essential constituent of any accelerator. There are a large variety of beam parameters, and total current is one of the most important parameters for accelerators. A current monitor is used to operate an accelerator efficiently and to improve the performance of the machine. A Faraday cup is the most fundamental current detection process, in which charged particles are stopped in the cup. However, this destructive method cannot be applied for high-current or high-energy beams because the total energy carried by the beam can destroy and activate the intercepting material. Therefore, non-destructive beam current measurement requires the use of current transformers that detect the magnetic field produced by the pulsed or DC beam. On the other hand, a new type of beam current monitor using a low-temperature superconducting (LTS) magnetic shield and an LTS SQUID was developed to measure the faint ion beams that are below the lowest measurable limit of the DC current transformer (DCCT) for atomic-physics studies. Recently, a prototype of a highly sensitive SQUID current monitor for measuring the intensity of faint beams, such as radioisotope beams, was completed for the RIKEN RI beam factory. This monitor is composed of a high-temperature superconducting (HTS) magnetic shield and an HTS SQUID. The first measurements using ion beams were carried out in the CNS experimental hall and RIKEN Ring Cyclotron (RRC). This paper first describes the principle of the conventional current monitor such as the Faraday cup and current transformers. Second, the progress of the LTS SQUID current monitor is discussed, and finally, the present status of the prototype of the LTS SQUID current monitor is discussed, and finally, the present status of the prototype of the HTS SQUID current monitor at RIKEN and the results of the first beam measurement are given. (author)

  18. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    International Nuclear Information System (INIS)

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio

  19. Accidental beam loss in superconducting accelerators: Simulations, consequences of accidents and protective measures

    International Nuclear Information System (INIS)

    The consequences of an accidental beam loss in superconducting accelerators and colliders of the next generation range from the mundane to rather dramatic, i.e., from superconducting magnet quench, to overheating of critical components, to a total destruction of some units via explosion. Specific measures are required to minimize and eliminate such events as much as practical. In this paper we study such accidents taking the Superconducting Supercollider complex as an example. Particle tracking, beam loss and energy deposition calculations were done using the realistic machine simulation with the Monte-Carlo codes MARS 12 and STRUCT. Protective measures for minimizing the damaging effects of prefire and misfire of injection and extraction kicker magnets are proposed here

  20. A Scintillating-fiber Beam Profile Monitor for the DAFNE BTF

    CERN Document Server

    Anelli, M; Mazzitelli, G; Valente, P

    2004-01-01

    A scintillating-fiber beam profile detector has been designed, built and tested, for the monitoring of the position and size of the electron beam of the DAFNE, the recently commissioned electron beam-test facility at the Frascati LNF. A description of the detector construction and assembly, together with the results achieved during the 2003-2004 run, are here reported.

  1. Operation of a thin scintillating fiber beam monitor at the COMPASS experiment 2010

    International Nuclear Information System (INIS)

    In 2010, a beam luminosity monitor built of scintillating fibers was used for the first time at the COMPASS experiment. The capability to efficiently monitor the high luminosity SPS muon beam with additional spatial information was one of the main incentives for this innovation. The detector consists of two planes with two layers of 64 scintillating fibers of 1mm diameter each. It is located 3m upstream of the polarized target and covers an active area of 4.2 x 4.2 cm2. Compared to the scintillating fiber detectors routinely used in COMPASS, the thickness is reduced by more than a factor of two to 2.5 mm for each plane. The losses of scintillation light are compensated by a close-by readout, omitting light guides between the active area and the photomultipliers. Furthermore, new high quantum efficiency photomultipliers (16 channel multi-anode PMTs, Hamamatsu H6568-100) are used in one of the layers to study the differences in the performance with respect to the conventional ones. A comparison to data from 2007 is presented as well as a detailed study of the performance with respect to other scintillating fiber detectors used in the COMPASS experiment.

  2. Calculated electronic energy loss of swift proton and helium ion beams in liquid water

    OpenAIRE

    Abril Sánchez, Isabel; García Molina, Rafael; Denton Zanello, Cristian D.; Emfietzoglou, Dimitris

    2008-01-01

    The electronic energy loss of swift proton and helium beams in liquid water is theoretically evaluated. Our model is based in the dielectric formalism, taking into account the charge exchange of the projectile during its travel through the target. The electronic properties of liquid water are described by the MELF-GOS model, where the outer electron excitations are represented by a sum of Mermin functions fitted to the experimental data in the optical limit, whereas the inner-shell electron e...

  3. Allotropic effects on the energy loss of swift H+ and He+ ion beams through thin foils

    OpenAIRE

    García Molina, Rafael; Abril Sánchez, Isabel; Denton Zanello, Cristian D.; Heredia Ávalos, Santiago

    2006-01-01

    We have developed a theoretical treatment and a simulation code to study the energy loss of swift H+ and He+ ion beams interacting with thin foils of different carbon allotropes. The former is based on the dielectric formalism, and the latter combines Monte Carlo with the numerical solution of the motion equation for each projectile to describe its trajectory and interactions through the target. The capabilities of both methods are assessed by the reasonably good agreement between their predi...

  4. Transient Thermal Analysis of Intense Proton Beam Loss on a Kicker Magnet Conductor Plate

    CERN Document Server

    Knaus, P

    2000-01-01

    The Super Proton Synchrotron SPS will be used as injector for the Large Hadron Collider LHC and needs adaptation to meet LHC requirements. The SPS injection kicker magnets MKP will undergo important modifications to comply with the requirements on magnetic field rise-time and ripple. The injection kicker presently installed has a return conductor of beryllium to minimise the risk of metal evaporation from its surface due to heating caused by beam impact. In the context of refurbishing the MKP to satisfy LHC requirements these conductors need replacement, preferably with a less delicate material. This article presents the transient thermal analysis of energy deposition caused by beam loss on the conductor plate. The expected time structure of the beam is taken into account. Simulations comparing different conductor materials have been performed, leading to the result that a significantly cheaper and fully inoffensive titanium alloy can satisfy the needs.

  5. Simulation of the ATLAS SCT Barrel Module Response to LHC Beam Loss Scenarios

    CERN Document Server

    Rose, P; The ATLAS collaboration; Fadeyev, V; Spencer, E; Wilder, M; Domingo, M

    2013-01-01

    In the event of beam loss at the LHC, ATLAS Inner Detector components nearest the beamline may be subjected to unusually large amounts of radiation. Understanding their behavior in such an event is important in determining whether they would still function properly. We built a SPICE model of the silicon strip module electrical system to determine the behavior of its elements during a realistic beam loss scenario. We found that the power supply and bias filter characteristics strongly affect the module response in such scenarios. In particular, the following self-limiting phenomena were observed: there is a finite amount of charge initially available on the bias filter capacitors for collection by the strips; the power supply current limit reduces the rate at which the bias filter capacitors' charge can be replenished; the reduced bias voltage leads to a smaller depletion depth which results in less collected charge. These effects provide a larger measure of safety during beam loss events than we have previous...

  6. Operational Experience with Beam Alignment and Monitoring Using Non-Destructive Beam Position Monitors in the Cyclotron Beamlines at iThemba LABS

    CERN Document Server

    Conradie, J L; Delsink, J L G; Fourie, D T; Kormany, Z; Mansfield, P T; Rohwer, P F; Sakildien, M

    2005-01-01

    At iThemba LABS proton beams, accelerated in a K=200 separated-sector cyclotron with a K=8 solid-pole injector cyclotron, are utilized for the production of radioisotopes and particle radiotherapy. Beams of heavy ions and polarized protons, pre-accelerated in a second injector cyclotron, are available for nuclear physics research. Beam position monitors have been developed for non-destructive alignment and continuous display of the beam position in the beam lines for the more intense beams used for therapy and the production of radioisotopes in cooperation* with Forschungszentrum Jülich. The monitors consist of four-section strip lines. Narrow-band super-heterodyne RF electronic equipment with automatic frequency and gain control measures the signals at the selected harmonic. A control module sequentially processes the signals and delivers calculated horizontal and vertical beam position data via a serial network to the computer control system. Eleven monitors have been installed in the transfer beam line be...

  7. Design alternatives for beam halo monitors in high intensity accelerators

    CERN Document Server

    Braun, H; Corsini, R; Lefèvre, T; Schulte, Daniel; Tecker, F A; Welsch, C P

    2005-01-01

    In future high intensity, high energy accelerators it must be ensured that particle losses are minimized as activation of the vacuum chambers or other components makes maintenance and upgrade work time consuming and costly. It is imperative to have a clear understanding of the mechanisms that can lead to halo formation and to have the possibility to test available theoretical models with an adequate experimental setup. Optical transition radiation (OTR) provides an interesting opportunity for linear real-time measurements of the transverse beam profile with a resolution which has been so far at best in the some μm range. However, the dynamic range of standard OTR systems is typically limited and needs to be improved for its application for halo measurements. In this contribution, the existing OTR system as it is installed in the CLIC test facility (CTF3) is analyzed and the contribution of each component to the final image quality discussed. Finally, possible halo measurement techniques based on OTR are pres...

  8. Advanced Photon Source RF Beam Position Monitor System Upgrade Design and Commissioning

    CERN Document Server

    Lill, R; Singh, O

    2001-01-01

    This paper describes the Advanced Photon Source (APS) storage ring mono-pulse rf beam position monitor (BPM) system upgrade. The present rf BPM system requires a large dead time of 400 ns between the measured bunch and upstream bunch. The bunch pattern is also constrained by the required target cluster of six bunches of 7 mA minimum necessary to operate the receiver near the top end of the dynamic range. The upgrade design objectives involve resolving bunches spaced as closely as 100 ns. These design objectives require us to reduce receiver front-end losses and reflections. An improved trigger scheme that minimizes systematic errors is also required. The upgrade is in the final phases of installation and commissioning at this time. The latest experimental and commissioning data and results will be presented.

  9. Commissioning and performance of the beam monitor system for XFEL/SPring-8 'SACLA'

    International Nuclear Information System (INIS)

    The beam monitor system for the XFEL facility 'SACLA' is demanded to measure a beam position with sub-μm resolution, a beam profile with few-μm resolution, a temporal structure with 10 fs resolution. Therefore, we developed and constructed the beam monitor system consisting of rf cavity beam position monitors (RF-BPM), screen monitors (SCM) with OTR targets and YAG:Ce scintillators, high-speed differential current transformers (CT), an rf deflector system (RFDEF), a streak camera and coherent synchrotron radiation (CSR) monitors. After the commissioning of the beam monitor system, the position resolution of the RF-BPM was found to be less than 0.6 μm (RMS) and the temporal resolution of the RFDEF was approximately 10 fs. Although SCMs observed anomalous radiation due to coherent OTR (COTR), COTR was diminished by a YAG:Ce target with an OTR mask. As a result of the beam tuning with the beam monitor system, SACLA succeeded the lasing with a wavelength of 0.12 nm. (author)

  10. Monte Carlo simulations to estimate the damage potential of electron beam and tests of beam loss detector based on quartz Cherenkov radiator read out by a silicon photomultiplier on CLIC Test Facility 3(CTF3)

    CERN Document Server

    Orfanelli, Styliani; Gazis, E

    The Compact Linear Collider (CLIC) study is a feasibility study aiming at the development of an electron/positron linear collider with a centre of mass energy in the multi-TeV energy range. Each Linac will have a length of 21 km, which means that very high accelerating gradients (>100 MV/m) are required. To achieve the high accelerating gradients, a novel two-beam acceleration scheme, in which RF power is transferred from a high-current, low-energy drive beam to the low-current, high energy main accelerating beam is designed. A Beam Loss Monitoring (BLM) system will be designed for CLIC to meet the requirements of the accelerator complex. Its main role as part of the machine protection scheme will be to detect potentially dangerous beam instabilities and prevent subsequent injection into the main beam or drive beam decelerators. The first part of this work describes the GEANT4 Monte Carlo simulations performed to estimate the damage potential of high energy electron beams impacting a copper target. The second...

  11. Experiments for the isotope separation of secondary beams with the momentum-loss achromat

    International Nuclear Information System (INIS)

    In the past the use of an intermediate energy absorber in combination with the two-stage magnetic system LISE and GANIL has proven to be a very powerful method for the isotropic separation of projectile-like reaction products in the intermediate energy range. At relativistic energies, the use of thicker targets allows us to increase the production rates, and the ambiguities in the selection caused by the occurrence of not completely stripped ions are considerably reduced. Cross contaminants due to parasitic nuclear interactions of the secondary beam in the energy absorber which were foreseen as the main disadvantage in using relativistic beams proved to be unimportant. The very good separation of the method demonstrated in these experiments at SATURNE is to a large extent due to the fact that the momentum spread caused by the fragmentation process decreases in relative terms with increasing beam energy. This leads to a comparatively effective separation already in the first section of the separator. In these experiments the momentum-loss achromat was able to produce very pure secondary beams of lighter ions. Any specific isotope could be selected by the choice of the ion-optical parameters. The authors expect this device to be suited also for the separation of heavy-ion beams up to uranium, whereby high-resolution magnetic systems are needed in order to reach the separation limit given by the energy straggling in the intermediate energy absorber

  12. Optimization of In-Beam Positron Emission Tomography for Monitoring Heavy Ion Tumor Therapy

    OpenAIRE

    Vieira Crespo, Paulo Alexandre

    2010-01-01

    In-beam positron emission tomography (in-beam PET) is currently the only method for an in-situ monitoring of highly tumor-conformed charged hadron therapy. In such therapy, the clinical effect of deviations from treatment planning is highly minimized by implementing safety margins around the tumor and selecting proper beam portals. Nevertheless, in-beam PET is able to detect eventual, undesirable range deviations and anatomical modifications during fractionated irradiation, to verify the accu...

  13. Digital Beam Position Monitor for the Happex Experiment

    International Nuclear Information System (INIS)

    The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high-precision (1 mm), high-bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM-010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The Multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a digital receiver daughter board and digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 4 MHz, and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with a resolution of one mm, 100 kHz output bandwidth, and overall latency of ten microseconds. The results are available in both analog and digital format

  14. Digital beam position monitor for the HAPPEX experiment

    International Nuclear Information System (INIS)

    The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high precision (1um), high bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a RF receiver daughter board and a digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 3 MHz and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with resolution of 1um, 100 kHz output bandwidth, and overall latency of 1us. The results are available in both the analog and digital format

  15. Monitoring the extracted proton beam at the SPS

    CERN Multimedia

    1977-01-01

    Fluorescent screens in front of the target positions allow a precise adjustement in front of them. A similar photo was recorded at the beam dump at the beam injection into the SPS, see Weekly Bulletin of April 1976.

  16. Development of capacitive beam position, beam current and Schottky-signal monitors for the Cryogenic Storage Ring (CSR)

    International Nuclear Information System (INIS)

    In this thesis novel techniques based on capacitive pickups for the determination of the beam current, the beam position and the Schottky-signal in storage rings have been developed. Beam current measurements at the heavy ion storage ring TSR with a capacitive pickup have been found in very good agreement with the theory. Using this device the accurate measurement of beam currents at the TSR far below 1 μA is now possible. This method will also be used at the Cryogenic Storage Ring (CSR) at which beam currents in the range of 1 nA-1 μA are expected. For the first time, position measurements with a resonant amplifier system for capacitive pickups have been examined at the TSR for later use of this technique in the CSR. With this method an increased signal-to-noise ratio can be achieved using a parallel inductance. A comparison with measurements using the rest gas beam profile monitor has shown very good agreement even at very low intensities. Experiments with the cryo-capable electronics for the CSR beam position monitors have shown an achievable quality factor of Q=500, resulting in the prospect of precise position measurements at the CSR even at very low beam currents. The CSR Schottky-Pickup will also be equipped with a resonant amplifier system with a comparable quality factor. An estimation of the signal-to-noise ratio suggests a detection limit of a few protons. (orig.)

  17. External beam monitoring of the Cyclone 30 cyclotron of IPEN-CNEN-SP

    International Nuclear Information System (INIS)

    Due to the increasing demand for cyclotron radioisotopes and the high cost of equipment and materials involved in the process, it becomes evident the importance of external beam monitoring of the cyclotron. In this way, the beam of the Cyclone 30 cyclotron of IPEN-CNEN/S P was characterized throughout the evaluation of its current intensity, profile (position, focus and geometry), alignment and homogeneity, by measuring currents, temperatures and pressures of irradiation systems. For this purpose, techniques and conventional devices, thermocouples and pressure sensors associated to electronic of instrumentation, and technology and flexibility of micro controllers allowed observing the beam behavior during irradiations in real time. The ion beam energy was also evaluated using activation analysis technique of monitor reactions in natCu. The beam monitoring systems have been contributing to prevent material damages and they have already been used in routine irradiations, bringing important advantages in the process of beam optimization of the Cyclone 30. (author)

  18. The new Beam Halo Monitor for the CMS experiment at the LHC

    CERN Document Server

    Tosi, Nicolo

    In the context of increasing beam energy and luminosity of the LHC accelerator at CERN, it will be important to accurately measure the Machine Induced Background. A new monitoring system will be installed in the CMS cavern for measuring the beam background at high radius. This detector, called the Beam Halo Monitor, will provide an online, bunch-by-bunch measurement of background induced by beam halo interactions, separately for each beam. The detector is composed of synthetic quartz Cherenkov radiators, coupled to fast UV sensitive photomultiplier tubes. The directional and fast response of the system allows the discrimination of the background particles from the dominant flux in the cavern induced by pp collision debris, produced within the 25 ns bunch spacing. The readout electronics of this detector will make use of many components developed for the upgrade of the CMS Hadron Calorimeter electronics, with a dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal will be d...

  19. Quench Tests of LHC Magnets with Beam: Studies on Beam Loss development and determination of Quench levels

    CERN Document Server

    Priebe, A; Sapinski, M

    The application of superconducting materials in the field of high energy accelerator physics not only opens the doors to the generation of the magnetic fields unattainable to normal conductors but also demands facing new challenges. A transition fromthe superconducting state, which is characterized by a resistance-free flow of the electric current, to the normal conducting state is called quenching. This process might be extremely dangerous and even lead to destruction of amagnet superconducting coil if no protecting actions are taken. Therefore, the knowledge of a magnet quench level, i.e. amount of energy which causes the transition to the resistive state, is crucial for the safety and operational efficiency of the accelerator. Regarding that, specific thresholds are incorporated to dedicated quench prevention systems in order to suppress the origin of detected energy perturbation, for example beam losses, or mitigate the consequences of the quenching process by dissipating the energy stored in the magnetic...

  20. Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

    CERN Document Server

    Rakhno, I L; Mokhov, N V; Sidorov, V I; Tropin, I S

    2012-01-01

    Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerabl...

  1. Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, I.L.; Drozhdin, A.I.; Mokhov, N.V.; Sidorov, V.I.; Tropin, I.S.; /Fermilab

    2012-05-14

    A fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-05 straight section is currently used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With the maximum magnetic field of 72.5 Gauss, it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-06 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using three horizontal kickers in the Long-12 section. STRUCT calculations show that using horizontal notchers, one can remove up to 96% of the 3-bunch intensity at 400-700 MeV, directing 95% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

  2. Prestress Loss and Bending Capacity of Pre-cracked 40 Year-Old PC Beams Exposed to Marine Environment

    Directory of Open Access Journals (Sweden)

    Dasar Amry

    2016-01-01

    Full Text Available Six prestressed concrete beams (PC beam were used for evaluation, consist of four post-tension beams (PC-O and two pre-tension beams (PC-R. In order to investigate the effect of crack on prestress loss and bending capacity after long-term exposed, prestressed concrete beams were pre-crack and then exposed to marine environment. Experimental work was carried out to evaluate PC beams performance after long-term exposed. In addition, visual observations and load bearing capacity test was carried out. Furthermore, evaluation of prestress loss conducted using three-point loading bending test and the remaining tendon forces in the beam were determined using Crack Re-opening Method. The experimental results revealed that prestress loss was increased due to corrosion of strand/wire which affected by the pre-crack on the prestressed beams. Approximately a prestress loss around 26% and 30% was recorded for post-tension and pre-tension beams respectively.

  3. Perturbation of the energy loss spectra for an accelerated electron beam due to the photo injector exit

    CERN Document Server

    Salah, W

    2003-01-01

    The influence of the photo-injector exit hall on the energy loss for an accelerated electron beam is investigated, by calculating the total energy transferred from the electrons to the wakefields, which are driven by the beam. The obtained energy loss is compared to those previously obtained for a 'pill-box' cavity. This comparison shows that the influence of this hall, in terms of energy loss, varies over the beam length. It is strongest in the middle of the beam and decreases towards both ends. In consequence of this perturbation, the center of the beam is displaced from its initial position during the first phase (t < 200 ps) where the exit aperture has no effect to a new equilibrium position which takes place at 200 < t < 250 ps. (author)

  4. Summary Of Session 4: How Do We Monitor Beam Quality?

    International Nuclear Information System (INIS)

    Up to the end of the 80's beam quality was mainly believed to be connected only to the intensity i.e. beam quantity. However, with the new colliders already functioning or programmed, new and more (also in safety) demanding production machines (e.g. isotope) and the many new 3rd generation synchrotron radiation sources that accommodate many experimental lines, the beam quality (BQ) issue has to be re-examined, re-evaluated and re-defined. (author)

  5. A micro-pattern gaseous detector for beam monitoring in ion-therapy

    Science.gov (United States)

    Terakawa, A.; Ishii, K.; Matsuyama, S.; Kikuchi, Y.; Togashi, T.; Arikawa, J.; Yamashita, W.; Takahashi, Y.; Fujishiro, F.; Yamazaki, H.; Sakemi, Y.

    2015-12-01

    A micro-pattern gaseous detector based on gas electron multiplier technology (GEM detector) was developed as a new transmission beam monitor for charged-particle therapy to obtain real-time information about the parameters of a therapeutic beam. Feasibility tests for the GEM detector were performed using an 80-MeV proton beam to evaluate the lateral intensity distributions of a pencil beam and the dose delivered to a target. The beam intensity distributions measured with the GEM detector were in good agreement with those measured with an imaging plate while the charge output from the GEM detector was in proportion to that of a reference dose monitor of an ionization chamber design. These experimental results showed that the GEM detector can be used not only as a beam monitor for the position and two-dimensional intensity distribution but also as a dose monitor. Thus, it is possible to simultaneously measure these beam parameters for beam control in charged-particle therapy using a single GEM-based transmission monitor.

  6. Silicon detectors for the n-TOF neutron beams monitoring

    OpenAIRE

    Cosentino, L.; Musumarra, A.; Barbagallo, M.; Colonna, N.; Damone, L.; Pappalardo, A.; Piscopo, M.; Finocchiaro, P.; collaboration, for the n-TOF

    2015-01-01

    During 2014 the second experimental area EAR2 was completed at the n-TOF neutron beam facility at CERN. As the neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target, the resulting neutron beam covers an enormous energy range, from thermal to several GeV. In this paper we describe two beam diagnostic devices, designed and built at INFN-LNS, both exploiting silicon detectors coupled with neutron converter foils containing 6Li. T...

  7. Detecting cell lysis using viscosity monitoring in E. coli fermentation to prevent product loss.

    Science.gov (United States)

    Newton, Joseph M; Schofield, Desmond; Vlahopoulou, Joanna; Zhou, Yuhong

    2016-07-01

    Monitoring the physical or chemical properties of cell broths to infer cell status is often challenging due to the complex nature of the broth. Key factors indicative of cell status include cell density, cell viability, product leakage, and DNA release to the fermentation broth. The rapid and accurate prediction of cell status for hosts with intracellular protein products can minimise product loss due to leakage at the onset of cell lysis in fermentation. This article reports the rheological examination of an industrially relevant E. coli fermentation producing antibody fragments (Fab'). Viscosity monitoring showed an increase in viscosity during the exponential phase in relation to the cell density increase, a relatively flat profile in the stationary phase, followed by a rapid increase which correlated well with product loss, DNA release and loss of cell viability. This phenomenon was observed over several fermentations that a 25% increase in broth viscosity (using induction-point viscosity as a reference) indicated 10% product loss. Our results suggest that viscosity can accurately detect cell lysis and product leakage in postinduction cell cultures, and can identify cell lysis earlier than several other common fermentation monitoring techniques. This work demonstrates the utility of rapidly monitoring the physical properties of fermentation broths, and that viscosity monitoring has the potential to be a tool for process development to determine the optimal harvest time and minimise product loss. © 2016 The Authors. Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers, 32:1069-1076, 2016. PMID:27111912

  8. Beam based gain calibration method for beam position monitor at J-PARC MR

    International Nuclear Information System (INIS)

    Stability of the closed orbit is one of very important points for stable operations to keep a small beam loss in MR. The relative gains of the output data may drift due to unpredictable imbalance among output signals from the pickup electrodes, because the output signals must travel through separate paths, such as cables, connectors, attenuators, switches, and then are measured by detectors. In KEKB, we found noticeable errors larger than 0.1mm in the almost all BPM readings. In KEKB, A non-linear chi-square method has received practical application to calibrate these errors come from the imbalance among 4 output voltage of a BPM. However, we were not able to apply a same method as KEKB to analyze a gain of BPMs in J-PARC. W noticed linear relations among 4 outputs voltage and analyzed the imbalance by the total least-squares method. This paper introduce the new method to estimate the related gains from four output data of a BPM head. (author)

  9. Loss of beam ions to the inside of the PDX [Poloidal Divertor Experiment] tokamak during the fishbone instability

    International Nuclear Information System (INIS)

    Using data from two vertical charge-exchange detectors on the Poloidal Divertor Experiment (PDX), we have identified a set of conditions for which loss of beam ions inward in major radius is observed during the fishbone instability. Previously, it was reported that beam ions were lost only to the outside of the PDX tokamak

  10. Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Early neutral-beam injection is used in the National Spherical Torus Experiment (NSTX) to heat the electrons and slow current penetration which keeps q(0) elevated to avoid deleterious MHD activity and at the same time reduces Ohmic flux consumption, all of which aids long-pulse operation. However, the low plasma current (Ip ∼ 0.5 MA) and electron density (ne ∼ 1 x 1013 cm-3) attending early injection lead to elevated orbit and shine through losses. The inherent orbit losses are aggravated by large excursions in the outer gap width during current ramp-up. An investigation of this behavior using various energetic particle diagnostics on NSTX and TRANSP code analysis is presented

  11. Updated analytical solutions of continuity equation for electron beams precipitation - II. Mixed energy losses

    Science.gov (United States)

    Zharkova, V. V.; Dobranskis, R. R.

    2016-06-01

    In this paper we consider simultaneous analytical solutions of continuity equations for electron beam precipitation (a) in collisional losses and (b) in ohmic losses, or mixed energy losses (MEL) by applying the iterative method to calculate the resulting differential densities at given precipitation depth. The differential densities of precipitating electrons derived from the analytical solutions for MELs reveal increased flattening at energies below 10-30 keV compared to a pure collisional case. This flattening becomes stronger with an increasing precipitation depth turning into a positive slope at greater precipitation depths in the chromosphere resulting in a differential density distribution with maximum that shifts towards higher energies with increase in column depth, while the differential densities combining precipitating and returning electrons are higher at lower energies than those for a pure collisional case. The resulting hard X-ray (HXR) emission produced by the beams with different initial energy fluxes and spectral indices is calculated using the MEL approach for different ratios between the differential densities of precipitating and returning electrons. The number of returning electrons can be even further enhanced by a magnetic mirroring, not considered in the present model, while dominating at lower atmospheric depths where the magnetic convergence and magnitude are the highest. The proposed MEL approach provides an opportunity to account simultaneously for both collisional and ohmic losses in flaring events, which can be used for a quick spectral fitting of HXR spectra and evaluation of a fraction of returning electrons versus precipitating ones. The semi-analytical MEL approach is used for spectral fitting to Reuven High Energy Solar Spectroscopic Imager observations of nine C, M and X class flares revealing a close fit to the observations and good resemblance to numerical FP solutions.

  12. OTR Based Monitor of Injection Beam for Top-Up Operation of the SPring-8

    CERN Document Server

    Takano, S; Masuda, T; Yamashita, A

    2005-01-01

    We have developed an OTR based monitor of injection beam at the SPring-8. The monitor has been installed near the injection point of the storage ring downstream of the beam transport line from the booster synchrotron. A screen made of an aluminum coated polyimide film is used as a nondestructive OTR radiator. A CCD camera with an electric shutter is used to observe the OTR image of the injection beam. The electric shutter is synchronized with the external injection trigger signals. At every injection, the image signal from the CCD camera is captured and analyzed by a personal computer, and the position, size and intensity of the injection beam are recorded by the common database of the SPring-8 control system. The OTR injection beam monitor provides real time and continuous diagnostic tool useful for the top-up operation of the SPring-8 storage ring.

  13. A new measurement method of electrode gains for orthogonal symmetric type beam position monitor

    CERN Document Server

    Zou, J Y; Yang, Y L; Sun, B G; Zhou, Z R; Luo, Q; Lu, P; Xu, H L

    2014-01-01

    The new beam position monitor (BPM) system of the injector at the upgrade project of Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonal symmetric stripline electrodes. The differences in electronic gain and mismachining tolerance can cause the change of the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions in order to bring the measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is irrelevant to the beam charge and the related coefficient can be theoretical calculated. The effect of electrodes coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

  14. Multiparametric ionization probes for monitoring accelerated particle beams

    International Nuclear Information System (INIS)

    Paper describes high-sensitive ionization probes of transverse cross section of accelerated particle beam. Image of beam real cross section is formed at the display of electron-optical converter on the basis of multichannel plates, is recorded by TV camera and is processes and presented by means of computer. Probe structures for 1-100 MeV energy round and strip beams are developed and tested. Distortions of beam cross section image under the effect of the external magnetic field and of space charge field are estimated. The results of the first investigations into prototype ionization probes to control form, duration, phase of cyclotron beam microclusters are presented. 13 refs.; 9 figs

  15. New Fast Beam Conditions Monitoring (BCM1F) system for CMS

    International Nuclear Information System (INIS)

    The CMS Beam Radiation Instrumentation and Luminosity (BRIL) project is composed of several systems providing the experiment protection from adverse beam conditions while also measuring the online luminosity and beam background. Although the readout bandwidth of the Fast Beam Conditions Monitoring system (BCM1F—one of the faster monitoring systems of the CMS BRIL), was sufficient for the initial LHC conditions, the foreseen enhancement of the beams parameters after the LHC Long Shutdown-1 (LS1) imposed the upgrade of the system. This paper presents the new BCM1F, which is designed to provide real-time fast diagnosis of beam conditions and instantaneous luminosity with readout able to resolve the 25 ns bunch structure

  16. Gas dynamics considerations in a non-invasive profile monitor for charged particle beams

    CERN Document Server

    Tzoganis, Vasilis; Welsch, Carsten P

    2014-01-01

    A non-invasive, gas jet-based, beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This allows on-line measurement of the 2-dimensional transverse profile of particle beams with negligible disturbance to either primary beam or accelerator vacuum. The monitor is suitable for use with beams across a wide range of energies and intensities. In this setup a nozzle-skimmer system shapes a thin supersonic gas jet into a curtain. However, the small dimensions of the gas inlet nozzle and subsequent skimmers were shown to be the cause of many operational problems. In this paper, the dynamics of gas jet formation transport and shaping is discussed before an image-processing based alignment technique is introduced. Furthermore, experimental results obtained with a 5 keV electron beam are discussed and the effects of gas stagnation pressure on the acquired beam are presented.

  17. New Fast Beam Conditions Monitoring (BCM1F) system for CMS.

    CERN Document Server

    Zagozdzinska, Agnieszka Anna

    2015-01-01

    The CMS Beam Radiation Instrumentation and Luminosity (BRIL) project is composed of several systems providing the experiment protection from adverse beam conditions while also measuring the online luminosity and beam background. Although the readout bandwidth of the Fast Beam Conditions Monitoring system (BCM1F - one of the faster monitoring systems of the CMS BRIL), was sufficient for the initial LHC conditions, the foreseen enhancement of the beams parameters after the LHC Long Shutdown-1 (LS1) imposed the upgrade of the system. This paper presents the new BCM1F, which is designed to provide real-time fast diagnosis of beam conditions and instantaneous luminosity with readout able to resolve the 25 ns sub-bunch structure.

  18. Design of a Standing-Wave Multi-Cavity Beam-Monitor for Simultaneous Beam Position and Emittance Measurements

    International Nuclear Information System (INIS)

    A high precision emittance measurement requires precise beam position at the measurement location. At present there is no existing technique, commercial or otherwise, for non-destructive pulse-to-pulse simultaneous beam position and emittance measurement. FARTECH, Inc. is currently developing a high precision cavity-based beam monitor for simultaneous beam position and emittance measurements pulse-to-pulse, without beam interception and without moving parts. The design and analysis of a multi-cavity standing wave structure for a pulse-to-pulse emittance measurement system in which the quadrupole and the dipole standing wave modes resonate at harmonics of the beam operating frequency is presented. Considering the Next Linear Collider beams, an optimized 9-cavity standing wave system is designed for simultaneous high precision beam position and emittance measurements. It operates with the π-quadrupole mode resonating at 16th harmonic of the NLC bunch frequency, and the 3 π/4 dipole mode at 12th harmonic (8.568 GHz). The 9-cavity system design indicates that the two dipoles resonate almost at the same frequency 8.583 GHz and the quadrupole at 11.427 GHz according to the scattering parameter calculations. The design can be trivially scaled so that the dipole frequency is at 8.568 GHz, and the quadrupole frequency can then be tuned during fabrication to achieve the desired 11.424 GHz. The output powers from these modes are estimated for the NLC beams. An estimated rms-beam size resolution is sub micro-meters and beam positions in sub nano-meters

  19. Construction and measurement techniques for the APS LEUTL project RF beam position monitors

    International Nuclear Information System (INIS)

    The design, construction, and assembly procedure of 24 rf beam position monitors used in the Advanced Photon Source low-energy undulator test line and linear accelerator (linac) are described. Beam stability as well as beam positioning capabilities are essential to the LEUTL project. A design objective of the LEUTL facility is to achieve better than 1- microm resolution. The highest care was used in the mechanical fabrication and assembly of the BPM units. The latest experimental results using these BPMs are presented

  20. Electron-optical monitoring of beam profile of a pulse accelerator

    International Nuclear Information System (INIS)

    Electron-optical methods of studying spatial-time characteristics of high-current electron beams on the basis of their bremsstrahlung are described. Data on dynamics of compression of electron beams of ORION-1 electrostatic accelerator, obtained under photochronographic monitoring at electron-optical converter, are presented. It is shown that in radial compression phase the rate of the beam inner boundary attains the value of ∼1.5x108 cm/s

  1. Proceedings of the meeting on beam monitors for Cyclotrons and related facilities

    International Nuclear Information System (INIS)

    The meeting on the beam monitors for Cyclotrons and related facilities was held at Institute for Nuclear Study, University of Tokyo on February 24, 1993. This proceedings contains all the paper presented at the meeting, covering the present status of the beam instruments and their performances. The coverage area of this meeting was the ion sources, the cyclotrons, the linacs, the synchrotrons and the beam transport system. The meeting consisted of 12 plenary talks and 30 scientists and engineers participated. (author)

  2. Fibre Monitoring System for the Beam Permit Loops at the LHC and Future Evolution of the Beam Interlock System

    CERN Document Server

    García-Argos, Carlos; Gabourin, Stéphane; Martin, Christophe; Puccio, Bruno; Siemko, Andrzej P

    2015-01-01

    The optical fibres that transmit the beam permit loop signals at the CERN accelerator complex are deployed along radiation areas. This may result in increased attenuation of the fibres, which reduces the power margin of the links. In addition, other events may cause the links to not function properly and result in false dumps, reducing the availability of the accelerator chain and affecting physics data taking. In order to evaluate the state of the fibres, an out-of-band fibre monitoring system is proposed, working in parallel to the actual beam permit loops. The future beam interlock system to be deployed during LHC long shutdown 2 will implement online, real-time monitoring of the fibres, a feature the current system lacks. Commercial off-the-shelf components to implement the optical transceivers are proposed whenever possible instead of ad-hoc designs.

  3. Reply to comment on 'Proton beam monitor chamber calibration'.

    Science.gov (United States)

    Gomà, Carles; Lorentini, Stefano; Meer, David; Safai, Sairos

    2016-09-01

    This reply shows that the discrepancy of about 3% between Faraday cup dosimetry and reference dosimetry using a cylindrical ionization chamber found in Gomà (2014 Phys. Med. Biol. 59 4961-71) seems to be due to an overestimation of the beam quality correction factors tabulated in IAEA TRS-398 for the cylindrical chamber used, rather than to 'unresolved problems with Faraday cup dosimetry', as suggested by Palmans and Vatnitsky (2016 Phys. Med. Biol. 61 6585-93). Furthermore, this work shows that a good agreement between reference dosimetry and Faraday cup dosimetry is possible, provided accurate beam quality correction factors for proton beams are used. The review on W air values presented by Palmans and Vatnitsky is believed to be inaccurate, as it is based on the imprecise assumption of ionization chamber perturbation correction factors in proton beams being equal to unity. PMID:27535895

  4. On scaling and optimization of high-intensity, low-beam-loss RF linacs for neutron source drivers

    International Nuclear Information System (INIS)

    RF linacs providing cw proton beams of 30--250 mA at 800--1600 MeV, and cw deuteron beams of 100--250 mA at 35--40 MeV, are needed as drivers for factory neutron sources applied to radioactive waste transmutation, advanced energy production, materials testing facilities, and spallation neutron sources. The maintenance goals require very low beam loss along the linac. Optimization of such systems is complex; status of beam dynamics aspects presently being investigated is outlined

  5. Albedo neutron dosimetry and monitoring around the RECH-1 reactor neutron radiographic beam

    International Nuclear Information System (INIS)

    This paper describes the neutrons and gamma monitoring and albedo neutron dosimetry in a field around the RECH-1 neutron beam. Two kind of albedo dosimeters were used: Hankins and KfK Alnor. The calibration procedures and comparison of these albedo dosimeters performance were done. The dose equivalent results agree between 28%. The neutron dose distribution for person working near the beam, was obtained by routine monitoring with albedo dosimeter developed by Hankins. A monthly neutron dose with a maximum of 0,8 mSv and arithmetic mean of 0,4 mSv were found. The beam's gamma energy spectrum and its related dose were also studied. (author)

  6. Hadron-therapy beam monitoring: Towards a new generation of ultra-thin p-type silicon strip detectors

    International Nuclear Information System (INIS)

    Hadron-therapy has gained increasing interest for cancer treatment especially within the last decade. System commissioning and quality assurance procedures impose to monitor the particle beam using 2D dose measurements. Nowadays, several monitoring systems exist for hadron-therapy but all show a relatively high influence on the beam properties: indeed, most devices consist of several layers of materials that degrade the beam through scattering and energy losses. For precise treatment purposes, ultra-thin silicon strip detectors are investigated in order to reduce this beam scattering. We assess the beam size increase provoked by the Multiple Coulomb Scattering when passing through Si, to derive a target thickness. Monte-Carlo based simulations show a characteristic scattering opening angle lower than 1 mrad for thicknesses below 20 μm. We then evaluated the fabrication process feasibility. We successfully thinned down silicon wafers to thicknesses lower than 10 μm over areas of several cm2. Strip detectors are presently being processed and they will tentatively be thinned down to 20 μm. Moreover, two-dimensional TCAD simulations were carried out to investigate the beam detector performances on p-type Si substrates. Additionally, thick and thin substrates have been compared thanks to electrical simulations. Reducing the pitch between the strips increases breakdown voltage, whereas leakage current is quite insensitive to strips geometrical configuration. The samples are to be characterized as soon as possible in one of the IBA hadron-therapy facilities. For hadron-therapy, this would represent a considerable step forward in terms of treatment precision. (authors)

  7. Bunch-length and beam-timing monitors in the SLC final focus

    International Nuclear Information System (INIS)

    During the 1997/98 luminosity run of the Stanford Linear Collider (SLC) two novel RF-based detectors were brought into operation, in order to monitor the interaction-point (IP) bunch lengths and fluctuations in the relative arrival time of the two colliding beams. Both bunch length and timing can strongly affect the SLC luminosity and had not been monitored in previous years. The two new detectors utilize a broad-band microwave signal, which is excited by the beam through a ceramic gap in the final-focus beam pipe and transported outside of the beamline vault by a 160-ft long X-Band waveguide. We describe the estimated luminosity reduction due to bunch-length drift and IP timing fluctuation, the monitor layout, the expected responses and signal levels, calibration measurements, and beam observations. copyright 1999 American Institute of Physics

  8. Beam position monitoring and feedback steering system at the photon factory

    International Nuclear Information System (INIS)

    A version of the beam steering servo system was used to vertically position and stabilize the synchrotron radiation beam at the Photon Factory. System components included a photon beam position monitor located 12 m from the bend magnet source point, a servo controller containing frequency compensation and gain circuits, and a 3-magnet orbital bump steering system. Two types of position monitor, one an ion chamber and the other on in-vacuum device, were used in the system. Vertical beam position noise spectra obtained from these monitors showed predominant peaks occurring at 14.5 Hz, 50 Hz, and at several other frequencies in the 1 to 100 Hz range. The closed-loop system was able to reduce low frequency positional offsets (< 0.1 Hz) by a factor of 1000, and the 14.5 Hz oscillation by a factor of 6

  9. Containment Structure Monitoring And Prestress Losses. Experience from Daya Bay Nuclear Power Plant

    International Nuclear Information System (INIS)

    This article describes the main characteristics of the containment structure of the Guangdong Nuclear Power Station (GNPS), located in Daya Bay, its monitoring devices for containment deformations, the measurement method, data treatment for prestress losses, and result assessment of the tendon relaxation

  10. Digital beam position and phase monitor for P-LINAC for FAIR

    International Nuclear Information System (INIS)

    For the planned P-LINAC for the FAIR facility, Beam Position Monitors (BPM) will be installed at 14 locations along the LINAC. The digital signal processing to derive the transverse beam position and the beam phase will be implemented by ''Libera Single Pass H''. The specification for position measurement is 0.1 mm spatial resolution and phase accuracy is 1 degree with respect to 325 MHz acceleration frequency. The results from the Libera digital signal processing were compared with the time-domain approach and the FFT analytic calculations. The first test was performed at the GSI UNILAC with a Ne4+ beam at 1.4 MeV / u. A single BPM was used to act as a ''Bunch arrival monitor'' to characterize the dependence of beam arrival time on bunch shape. The signals were sampled at 117.440 MHz with a 16-bit ADC to produce I and Q data streams. The first experimental results are reported.

  11. Study of beam parameters of the CERN proton linac using a three dimensional bunch shape monitor

    International Nuclear Information System (INIS)

    A Three Dimensional Bunch Shape Monitor (3D-BSM) has been developed for the CERN Proton Linac 2. A new area for beam studies at high intensities has been opened by this detector. Bunch density distributions in all three dimensions and their variations along the beam pulse can be obtained. Changing field gradients in linac quadrupoles, emittance variation along the bunch has been calculated. Measurements of beam halos become possible thanks to the large dynamic range of the device. Beam parameters at various linac settings have been measured and analysed. (author)

  12. Study of beam parameters of the CERN proton linac using a three dimensional bunch shape monitor

    CERN Document Server

    Feschenko, A V; Ostroumov, P N; Dubois, O; Haseroth, H; Hill, C; Kugler, H; Lombardi, A M; Naito, F; Tanke, E; Vretenar, Maurizio

    1996-01-01

    A Three Dimensional Bunch Shape Monitor (3D-BSM) has been developed for the CERN Proton Linac 2. A new area for beam studies at high intensities has been opened by this detector. Bunch density distributions in all three dimensions and their variations along the beam pulse can be obtained. Changing field gradients in linac quadrupoles, emittance variation along the bunch has been calculated. Measurements of beam halos become possible thanks to the large dynamic range of the device. Beam parameters at various linac settings have been measured and analysed.

  13. Longitudinal Bunch Shape Monitor Using the Beam Chopper of the J-PARC

    CERN Document Server

    Naito, F

    2004-01-01

    We propose the longitudinal bunch shape monitor for the low energy part of the linac of the J-PARC. The monitor uses the beam chopper cavity installled in the MEBT line between thr RFQ and the DTL of the J-PARC as a kind of the bunch rotator. Consequentry the longitudinal bunch shape is measured along the horizontal direction. If we can measure the energy distribution of the bunch also, the longitudinal emittance of the beam is derived. In the paper, the basic idea of the monitor is discussed in detail.

  14. A Fast Non Intercepting Linac Electron Beam Position and Current Monitor

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Wille, Mads

    A non-intercepting beam monitor consisting of four detecting loops is used to determine the spatial postion and current of a pulsed beam from an electron linear accelerator. The monitor detects the magnetic field radiated by the substructure of the electron bunches created by the accelerating...... microwave. The detecting loops are interconnected two by two, by means of two coaxial hybrid junctions, the two sets positioned perpendicular to each other. By means of the two signals from the diametrically positioned detecting loops, a good spatial displacement and current monitoring sensitivity are...

  15. Plasma Charge Current for Controlling and Monitoring Electron Beam Welding with Beam Oscillation

    Science.gov (United States)

    Trushnikov, Dmitriy; Belenkiy, Vladimir; Shchavlev, Valeriy; Piskunov, Anatoliy; Abdullin, Aleksandr; Mladenov, Georgy

    2012-01-01

    Electron beam welding (EBW) shows certain problems with the control of focus regime. The electron beam focus can be controlled in electron-beam welding based on the parameters of a secondary signal. In this case, the parameters like secondary emissions and focus coil current have extreme relationships. There are two values of focus coil current which provide equal value signal parameters. Therefore, adaptive systems of electron beam focus control use low-frequency scanning of focus, which substantially limits the operation speed of these systems and has a negative effect on weld joint quality. The purpose of this study is to develop a method for operational control of the electron beam focus during welding in the deep penetration mode. The method uses the plasma charge current signal as an additional informational parameter. This parameter allows identification of the electron beam focus regime in electron-beam welding without application of additional low-frequency scanning of focus. It can be used for working out operational electron beam control methods focusing exactly on the welding. In addition, use of this parameter allows one to observe the shape of the keyhole during the welding process. PMID:23242276

  16. Luminosity, Beamstrahlung energy loss and beam-beam deflections for e+e- and e-e- collisions at the ILC with 500 GeV and varying transverse beam sizes

    International Nuclear Information System (INIS)

    At the interaction point of the International Linear Collider, beam-beam effects due to the strong electromagnetic fields that the bunches experience during collisions cause a mutual focusing, called pinch effect, which enhances the luminosity in the case of e+e- collisions. The opposite is true for e-e- collisions. In this case the luminosity is reduced by mutual defocusing, or anti-pinching. The resulting Beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are also different for both modes of operation. The dependence of these quantities with transverse beam sizes are presented for the case of e-e- collisions

  17. Secondary emission monitor for keV ion and antiproton beams

    CERN Document Server

    Sosa, Alejandro; Bravin, Enrico; Harasimowciz, Janusz; Welsch, C P

    2013-01-01

    Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Sec- ondary electron Emission Monitor (SEM) has been de- signed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.

  18. Performance evaluation of a beam profile monitor using Fresnel Zone Plates

    International Nuclear Information System (INIS)

    We have developed a high resolution beam profile monitor using two Fresnel Zone Plates (FZPs). To evaluate the resolution of this monitor, we computed 'Fresnel-Kirchhoff diffraction integral' to the detector position from the source point using Monte Carlo methods. From this calculation, the spatial resolution of this monitor is less than 1 μm. We also computed the effect of the inclined first FZP. And we compared with experimental result of the FZP inclination effect. (author)

  19. Retrograde amnesia produced by electron beam exposure: causal parameters and duration of memory loss

    International Nuclear Information System (INIS)

    The production of retrograde amnesia (RA) upon electron beam exposure has been investigated. RA production was evaluated using a single-trial avoidance task across a 104 dose range for 10-, 1-, and 0.1-μsec pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 106 rad/sec. By employing a 10 rad (106 rad/sec) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory activation which provided a novel stimulus that masked previous stimuli

  20. Retrograde amnesia produced by electron beam exposure: causal parameters and duration of memory loss. [Rats

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T.G.; Hardy, K.A.

    1985-01-01

    The production of retrograde amnesia (RA) upon electron beam exposure has been investigated. RA production was evaluated using a single-trial avoidance task across a 10/sup 4/ dose range for 10-, 1-, and 0.1-..mu..sec pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 10/sup 6/ rad/sec. By employing a 10 rad (10/sup 6/ rad/sec) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory activation which provided a novel stimulus that masked previous stimuli.

  1. Induced Optical Losses in Optoelectronic Devices due to Focused Ion Beam Damages

    CERN Document Server

    Vallini, Felipe; Reis, Elohim Fonseca dos; von Zuben, Antônio Augusto; Frateschi, Newton Cesário

    2012-01-01

    A study of damages caused by gallium focused ion beam (FIB) into III-V compounds is presented. Potential damages caused by local heating, ion implantation, and selective sputtering are presented. Preliminary analysis shows that local heating is negligible. Gallium implantation is shown to occur over areas tens of nanometers thick. Gallium accumulation as well as selective sputtering during III-V compounds milling is expected. Particularly, for GaAs, this effect leads to gallium segregation and formation of metallic clusters. Microdisk resonators were fabricated using FIB milling with different emission currents to analyze these effects on a device. It is shown that for higher emission current, thus higher implantation doses, the cavity quality factor rapidly decreases due to optical scattering losses induced by implanted gallium atoms.

  2. Structural activation calculations due to proton beam loss in the APT accelerator design

    International Nuclear Information System (INIS)

    For the new, high-power accelerators currently being designed, the amount of activation of the accelerator structure has become an important issue. To quantify this activation, a methodology was utilized that coupled transport and depletion codes to obtain dose rate estimates at several locations near the accelerator. This research focused on the 20 and 100 MeV sections of the Bridge-Coupled Drift Tube Linear Accelerator. The peak dose rate was found to be approximately 6 mR/hr in the 100 MeV section near the quadrupoles at a 25-cm radius for an assumed beam loss of 1 nA/m. It was determined that the activation was dominated by the proton interactions and subsequent spallation product generation, as opposed to the presence of the generated neutrons. The worst contributors were the spallation products created by proton bombardment of iron, and the worst component was the beam pipe, which consists mostly of iron. No definitive conclusions about the feasibility of hands-on maintenance can be determined, as the design is still not finalized

  3. Development and optimization of the LHC and the SPS beam diagnostics based on synchrotron radiation monitoring

    International Nuclear Information System (INIS)

    Measuring the beam transverse emittance is fundamental in every accelerator, in particular for colliders, where its precise determination is essential to maximize the luminosity and thus the performance of the colliding beams. Synchrotron Radiation (SR) is a versatile tool for non-destructive beam diagnostics, since its characteristics are closely related to those of the source beam. At CERN, being the only available diagnostics at high beam intensity and energy, SR monitors are exploited as the proton beam size monitor of the two higher energy machines, the Super Proton Synchrotron (SPS) and the Large Hadron Collider (LHC). The thesis work documented in this report focused on the design, development, characterization and optimization of these beam size monitors. Such studies were based on a comprehensive set of theoretical calculations, numerical simulations and experiments. A powerful simulation tool has been developed combining conventional softwares for SR simulation and optics design, thus allowing the description of an SR monitor from its source up to the detector. The simulations were confirmed by direct observations, and a detailed performance studies of the operational SR imaging monitor in the LHC, where different techniques for experimentally validating the system were applied, such as cross-calibrations with the wire scanners at low intensity (that are considered as a reference) and direct comparison with beam sizes de-convoluted from the LHC luminosity measurements. In 2015, the beam sizes to be measured with the further increase of the LHC beam energy to 7 TeV will decrease down to ∼190 μm. In these conditions, the SR imaging technique was found at its limits of applicability since the error on the beam size determination is proportional to the ratio of the system resolution and the measured beam size. Therefore, various solutions were probed to improve the system's performance such as the choice of one light polarization, the reduction of

  4. Improvement of thermo-mechanical position stability of the beam position monitor in PLS-II

    CERN Document Server

    Ha, Taekyun; Kwon, Hyuckchae; Han, Hongsik; Park, Chongdo

    2016-01-01

    In the storage ring of PLS-II, we reduced mechanical displacement of electron beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The orbit feedback system intends that the electron beam pass through the center of the BPM, so to provide stable photon beam into beamlines the BPM pickup itself must be stable to sub-micrometer precision. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report the thermo-mechanical analysis and displacement measurements of BPM pickups after the improvements.

  5. Cancellation of thermal deformation effect of the initial mirror on the beam profile monitor line

    International Nuclear Information System (INIS)

    The electron storage ring NewSUBARU has a visible light beam monitor line SR5. The two dimensional beam image obtained on this line is used in various beam diagnostics, such as a streak camera and a gated ICCD camera. One problem of this line was a stored current dependence of its imaging property. This was due to the mirror deformation produced by a heat load of synchrotron radiation. The effect of this deformation is approximated by a defocusing function in the lowest order. A simple defocusing can be handled by an adjustment of the assumed beam image position. However, the deformation was different for the horizontal and vertical directions. We installed a weak cylindrical lens to eliminate this difference. The current dependent imbalance of the deformation was cancelled by changing location of the lens according to the prediction. We succeeded to obtain a good two dimensional beam image at any electron beam energy and stored current. (author)

  6. Up-scattering of beam ions by nuclear elastic scattering and its effect on energy loss rate in thermonuclear plasmas

    International Nuclear Information System (INIS)

    An expression for the average energy loss rate of beam ions due to nuclear elastic scattering (NES) in Maxwellian plasmas is derived, by taking into consideration the thermal motion of the background ions. The NES effect on deuterium beam injection plasma heating is examined using the expression derived. As a result of the scattering due to NES of the slowing down deuterons up to the higher energy range, the average energy loss rate due to NES of 1 MeV deuterons in 20 keV deuterium plasmas decreases by about 60% compared with the case of cold background plasmas. An examination is also made of the fraction of the beam energy deposited to ions. It is shown that when the beam energy is higher than 1 MeV, the increase in the fraction due to NES becomes appreciable. (author). Letter-to-the-editor

  7. Single shot laser flash photolysis with a fibre-coupled reference beam monitor.

    Science.gov (United States)

    Li, Heng; van 't Hag, Leonie; Yousef, Yaser A; Melø, T B; Razi Naqvi, K

    2013-02-01

    In the standard nanosecond laser photolysis method for kinetic studies, a Q-switched laser generates transient species, and absorption spectrophotometry provides a measure of their concentrations. The sample is placed between the monitoring source (a pulsed xenon arc or a flash lamp) and a monochromator, and a photomultiplier tube (PMT) is used for measuring the intensity of the light leaving the exit slit of the monochromator. With this (single-beam) arrangement, the laser-induced change in the absorbance of the sample, ΔA, can be calculated only if the intensity of the monitoring beam remains constant during the time interval of interest. When this condition is not fulfilled, a second measurement of the PMT output is made after blocking the path of the laser beam, but shot-to-shot variations in the output of the monitoring source vitiate the analysis when ΔA is small. To overcome this problem, double-beam versions were developed in the last century, but the single-beam version still enjoys greater popularity. With a view to making the double-beam method easily implementable, some simple modifications are introduced, which permit the conversion of an existing laser kinetic spectrometer into a double-beam variant (with one or two monochromators). PMID:22990442

  8. Design, construction and characterization of special ionization chambers for X radiation beams monitoring

    International Nuclear Information System (INIS)

    X radiation equipment may show fluctuations in the radiation beam intensity, as they are connected to the power net. These intensity variations can, in turn, modify the air kerma rate produced by this radiation beam. In a calibration laboratory, where radiation detectors (from clinics and hospital services) are calibrated, variations in the radiation beam intensity may cause an error in the absorbed dose determination. The monitor ionization chambers are used to verify the radiation beam intensity constancy, and to provide a correction for possible fluctuations. In this work, monitor ionization chambers for X radiation beams were designed, assembled and characterized. The developed ionization chambers have an innovative design, ring-shaped, with aluminium or graphite electrodes. These ring-shaped ionization chambers have the advantage of not interfering in the direct radiation beams. A double-volume ionization chamber with graphite electrodes was also developed. This ionization chamber is similar to the commercial monitor ionization chamber used in the Calibration Laboratory of the Instituto de Pesquisas Energeticas e Nucleares. All developed ionization chambers were tested in several standardized radiation beams and their performances were compared with those of commercial ionization chambers. The results show that two of the four ionization chambers developed showed performance comparable to that of the commercial ionization chambers tested. Besides presenting good results, the ionization chambers were designed and manufactured using low cost materials, which are easily found on the Brazilian market. (author)

  9. Noninterceptive method to measure longitudinal Twiss parameters of a beam in a hadron linear accelerator using beam position monitors

    Science.gov (United States)

    Shishlo, A.; Aleksandrov, A.

    2013-06-01

    A new method of measuring of the rms longitudinal Twiss parameters of a beam in linear accelerators is presented. It is based on using sum signals from beam position monitors sensitive to the longitudinal charge distribution in the bunch. The applicability of the method is demonstrated on the superconducting section of the Oak Ridge Spallation Neutron Source linear accelerator. The results are compared to a direct measurement of the bunch longitudinal profiles using an interceptive bunch shape monitor in the linac warm section of the same accelerator. Limitations of the method are discussed. The method is fast and simple, and can be used to obtain the initial parameters for the longitudinal matching in linear accelerators where interceptive diagnostics are not desirable.

  10. Monitoring road losses for Lushan 7.0 earthquake disaster utilization multisource remote sensing images

    Science.gov (United States)

    Huang, He; Yang, Siquan; Li, Suju; He, Haixia; Liu, Ming; Xu, Feng; Lin, Yueguan

    2015-12-01

    Earthquake is one major nature disasters in the world. At 8:02 on 20 April 2013, a catastrophic earthquake with Ms 7.0 in surface wave magnitude occurred in Sichuan province, China. The epicenter of this earthquake located in the administrative region of Lushan County and this earthquake was named the Lushan earthquake. The Lushan earthquake caused heavy casualties and property losses in Sichuan province. After the earthquake, various emergency relief supplies must be transported to the affected areas. Transportation network is the basis for emergency relief supplies transportation and allocation. Thus, the road losses of the Lushan earthquake must be monitoring. The road losses monitoring results for Lushan earthquake disaster utilization multisource remote sensing images were reported in this paper. The road losses monitoring results indicated that there were 166 meters' national roads, 3707 meters' provincial roads, 3396 meters' county roads, 7254 meters' township roads, and 3943 meters' village roads were damaged during the Lushan earthquake disaster. The damaged roads mainly located at Lushan County, Baoxing County, Tianquan County, Yucheng County, Mingshan County, and Qionglai County. The results also can be used as a decision-making information source for the disaster management government in China.

  11. Construction of a high resolution electron beam profile monitor

    International Nuclear Information System (INIS)

    Bremsstrahlung from an electron beam on a heavy target can be used to image the beam profile using collimators and slits. The limiting resolution using this system is determined by Fresnel diffraction, and is ∼ √(λd/2), where λ is the photon wavelength and d is determined by the linear dimensions of the system. For linear colliders this resolution could be a few nm. The highest resolution requires detectors which see only high energy, (small λ), photons, and this is accomplished by converting photons to pairs, and detecting Cherenkov light in a nearly forward angle with a CCD detector or streak camera. Tests are planned at the Argonne APS and SLAC FFTB

  12. SQUID-based beam position monitoring for proton EDM experiment

    Science.gov (United States)

    Haciomeroglu, Selcuk

    2014-09-01

    One of the major systematic errors in the proton EDM experiment is the radial B-field, since it couples the magnetic dipole moment and causes a vertical spin precession. For a proton with EDM at the level of 10-29 e.cm, 0.22 pG of B-field and 10.5 MV/m of E-field cause same vertical spin precession. On the other hand, the radial B-field splits the counter-rotating beams depending on the vertical focusing strength in the ring The magnetic field due to this split modulated at a few kHz can be measured by a SQUID-magnetometer. This measurement requires the B-field to be kept less than 1 nT everywhere around the ring using shields of mu-metal and aluminum layers. Then, the SQUID measurements involve noise from three sources: outside the shields, the shields themselves and the beam. We study these three sources of noise using an electric circuit (mimicking the beam) inside a magnetic shielding room which consists two-layers of mu-metal and an aluminum layer.

  13. A Gas-Jet Profile Monitor for the CLIC Drive Beam

    CERN Document Server

    Jeff, A; Lefevre, T; Tzoganis, V; Welsch, C P

    2013-01-01

    The Compact Linear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads for some distance down the beam pipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam crosssectionis imaged. In this paper we present some arrangements for the generation of such a jet. In ...

  14. Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators

    CERN Document Server

    Fernandes, M; Soby, L; Welsch, CP

    2013-01-01

    In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results f...

  15. Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

    Science.gov (United States)

    Cullinan, F. J.; Boogert, S. T.; Farabolini, W.; Lefevre, T.; Lunin, A.; Lyapin, A.; Søby, L.; Towler, J.; Wendt, M.

    2015-11-01

    The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2 /3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

  16. Investigations into beam monitors at the AE bar {g}IS experiment

    Science.gov (United States)

    Sosa, A.; Bravin, E.; Harasimowicz, J.; Jeff, A.; Welsch, C. P.

    2014-02-01

    Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE bar {g}IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE bar {g}IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented.

  17. Piezoelectric-based smart sensing system for I-beam structural health monitoring

    Science.gov (United States)

    Zhang, Chen; Zhang, Haifeng; Yu, Tzuyang; Wang, Xingwei

    2016-04-01

    In recent decades, the I-beam has become one of the most important engineering structural components being applied in areas such as mechanical, civil, and constructional engineering. To ensure safety and proper maintenance, an effective and accurate structural health monitoring method/system for I-beams is urgently needed. This paper proposes a smart sensing system for I-beam crack detection that is based on the energy diffusivity (attenuation) between two individual piezoelectric transducers (PZTs). Sensor (one of the PZTs) responses are analyzed and applied to characterize the health status of the I-beam. Lab experiments are carried out for effective evaluation of this approach in structural health monitoring. The characteristics of crack distribution are studied by calculating and analyzing the energy diffusivity variation of the sensor responses to artificially cuttings to the I-beam. Moreover, instead of utilizing an actuator and a sensor, the system employs a couple of PZTs sensors, which offer the potential for in-field, in situ sensing with the sensor arrays. This smart sensing system can be applied in railway, metro, and iron-steel structures for I-beam health monitoring applications.

  18. Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngim; /Kyungpook Natl. U.; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Boogert, Stewart; /Royal Holloway, U. of London; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Smith, Tonee; /SLAC

    2012-08-14

    Nanometer resolution beam position monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam has to be measured to within a few nanometers at the interaction point. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal point (IP). The second goal is to stabilize the beam at the focal point at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.

  19. Use of active-edge silicon detectors as X-ray beam monitors

    International Nuclear Information System (INIS)

    Silicon detectors have been developed which are active to within several microns of the physical edge of the detector. These active-edge devices can be placed near an intense X-ray beam to accurately measure the X-ray beam properties. In addition, they can be fabricated in a variety of geometries that will be useful for monitoring the intensity, profile, and position of synchrotron X-ray beams. One shape is a detector with a through hole surrounded by four active elements. The hole allows the intense X-ray beam to go through the center while the four elements can detect any change in the position or dispersion of the beam. Another shape is a rectangular 5 mm longx0.5 mm wide device with a set of four elements that are 100 μm wide. These devices could be mounted on the upstream side of the jaws of an x-y collimating slit to measure the intensity profile of the beam that each jaw of the slit is stopping. Small detectors could also be mounted in a cylindrical beam stop to give on-line beam intensity measurements. A variety of different geometries were tested at beamline 10.3.1 of the Advanced Light Source using a 12.5 keV X-ray beam. They have wide dynamic range, excellent position sensitivity and low sensitivity to radiation damage

  20. Detecting cell lysis using viscosity monitoring in E. coli fermentation to prevent product loss

    OpenAIRE

    Newton, J. M.; Schofield, D.; Vlahopoulou, J.; Zhou, Y.

    2016-01-01

    Monitoring the physical or chemical properties of cell broths to infer cell status is often challenging due to the complex nature of the broth. Key factors indicative of cell status include cell density, cell viability, product leakage and DNA release to the fermentation broth. The rapid and accurate prediction of cell status for hosts with intracellular protein products can minimise product loss due to leakage at the onset of cell lysis in fermentation. This paper reports the rheological exa...

  1. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    CERN Document Server

    Church, Mike; 10.1063/1.3520295

    2012-01-01

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  2. A Monitor and Control System for the Synchrotron Radiation Beam Lines at DAΦNE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Three synchrotron radiation beam lines have been built on DAΦNE,the Frascati electron-positron accelerator.It is Possible to monitor and control all the elements on the beam lines using a modular network distributed I/O system by National Instrunments (FieldPoint) with Bridge VIEW/Lab VIEW programs,Two of these beam lines have radiation safety problems solved by two independent and redundant systems,using mechanical switches ,and S7-200 PLC's by Siemens.In this article our solution will be described in details.

  3. Development of button-type beam position monitor for superKEKB

    International Nuclear Information System (INIS)

    Button-type beam position monitors for SuperKEKB rings have been designed. The RF characteristics such as beam response, trapped modes or wake functions have been simulated using 3-D E-M codes such as GdfidL and HFSS. The estimated instability threshold from the trapped modes was much higher than the radiation damping time. The prototype units have been tested in the prototype-antechambers installed in Nikko straight section and D6 arc sections. The mechanical reliability and the beam responses are also reported. (author)

  4. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    International Nuclear Information System (INIS)

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  5. Summary Report of Working Group 5: Beam and Radiation Generation, Monitoring, and Control

    International Nuclear Information System (INIS)

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  6. The Study of a Beam Profile Monitor based on Faraday Cup Array

    International Nuclear Information System (INIS)

    The metal can then be discharged to measure a small current equivalent to the number of impinging ions. The beam current can be measured and used to determine the number of ions or electrons hitting the cup. Recently, beam profile monitor (BPM) based on Faraday cup array (FCA), which represented beam position through the spatial and temporal distribution of the beam current, has been studied due to advantages of measure of wide-range ion beam current. FCA system is divided into a FC, an electrical circuit and display parts. We have studied FCA to monitor beam profile on an electrostatic accelerator with wide-range ion current. In this paper, we represented basic characteristics and designs for the fabricated FCA. FCA system, which consisted of FC system, electronic readout system, and output display, was suggested to measure ion beam current, efficiently. FC system consisted of a collimator, suppressor, tiny FC, insulator frame, and circuit board divided into elec PCB, cap PCB, and con PCB. FC size was 4 mm diameters and FCA system was considered as 8 x 8 array and whole size of 8 x 8 mm''2. FCA system was set-up in vacuum chamber and an integrator and output display parts were formed out of chamber to minimize number of feed-through

  7. The Study of a Beam Profile Monitor based on Faraday Cup Array

    Energy Technology Data Exchange (ETDEWEB)

    Park, K. M.; Park, S. H.; Kim, S. G.; Kwon, H. J.; Cho, Y. S. [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The metal can then be discharged to measure a small current equivalent to the number of impinging ions. The beam current can be measured and used to determine the number of ions or electrons hitting the cup. Recently, beam profile monitor (BPM) based on Faraday cup array (FCA), which represented beam position through the spatial and temporal distribution of the beam current, has been studied due to advantages of measure of wide-range ion beam current. FCA system is divided into a FC, an electrical circuit and display parts. We have studied FCA to monitor beam profile on an electrostatic accelerator with wide-range ion current. In this paper, we represented basic characteristics and designs for the fabricated FCA. FCA system, which consisted of FC system, electronic readout system, and output display, was suggested to measure ion beam current, efficiently. FC system consisted of a collimator, suppressor, tiny FC, insulator frame, and circuit board divided into elec PCB, cap PCB, and con PCB. FC size was 4 mm diameters and FCA system was considered as 8 x 8 array and whole size of 8 x 8 mm''2. FCA system was set-up in vacuum chamber and an integrator and output display parts were formed out of chamber to minimize number of feed-through.

  8. Two-dimensional beam profile monitor having high dynamic range by using multi-screen

    International Nuclear Information System (INIS)

    A two-dimensional beam profile monitor with a high dynamic range for 3-50 BT at J-PARC has been developed. For measuring the beam core and the halo alternatively, the monitor has three kinds of screens. The first one is titanium foil OTR screen (thickness of 10 μm) to measure a beam core, the second one is aluminum foil OTR screen (thickness of 100 μm) having a hole (50 mm diameter) in the center, and the last one is a pair of alumina fluorescent screen with a separation of 80 mm in horizontal to observe the beam halo in surroundings. We designed an optical system based on the Offner optics for the observation of fluorescence and OTR lights. This optical system has an entrance aperture of 300 mm and it can cover the large opening angle (+/- 13.5 degree) of the OTR from 3 GeV protons. A CID camera with an image intensifier (I.I.) was use to observe the profile. We have succeeded to observe a profile of beam halo to 10-6 order to the peak of beam core by using proton beams of 3 GeV, 9.6 x 1012 protons/2bunch by this multi-screen scheme. (author)

  9. Radiation damage in the diamond based beam condition monitors of the CMS experiment at the Large Hadron Collider (LHC) at CERN

    CERN Document Server

    Guthoff, Moritz; Dabrowski, Anne; De Boer, Wim; Stickland, David; Lange, Wolfgang; Lohmann, Wolfgang

    2013-01-01

    The Beam Condition Monitor (BCM) of the CMS detector at the LHC is a protection device similar to the LHC Beam Loss Monitor system. While the electronics used is the same, poly-crystalline Chemical Vapor Deposition (pCVD) diamonds are used instead of ionization chambers as the BCM sensor material. The main purpose of the system is the protection of the silicon Pixel and Strip tracking detectors by inducing a beam dump, if the beam losses are too high in the CMS detector. By comparing the detector current with the instantaneous luminosity, the BCM detector ef fi ciency can be monitored. The number of radiation-induced defects in the diamond, reduces the charge collection distance, and hence lowers the signal. The number of these induced defects can be simulated using the FLUKA Monte Carlo simulation. The cross-section for creating defects increases with decreasing energies of the impinging particles. This explains, why diamond sensors mounted close to heavy calorimeters experience more radiation damage, becaus...

  10. Development of a Propagating Millimeter-Wave Beam Position and Profile Monitor in the Oversize Corrugated Waveguide Used in an ECRH System

    Science.gov (United States)

    Shimozuma, Takashi; Kobayashi, Sakuji; Ito, Satoshi; Ito, Yasuhiko; Kubo, Shin; Yoshimura, Yasuo; Nishiura, Masaki; Igami, Hiroe; Takahashi, Hiromi; Mizuno, Yoshinori; Okada, Kohta; Mutoh, Takashi

    2016-01-01

    In a high-power electron cyclotron resonance heating (ECRH) system for plasma heating, a long-distance and low-loss transmission system of the millimeter wave is required. A real-time monitor of the millimeter-wave beam position and its intensity profile, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam-position and profile monitor (BPM) consists of a reflector, Peltier-device array, and a heat-sink, which is installed in the reflector-plate of a miterbend. The BPM was tested using both simulated electric heater power and high-power gyrotron output power. The profile obtained from the monitor using the gyrotron output was well agreed with the burn patter on a thermal sensitive paper. Methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated waveguide are proposed.

  11. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G [Stanford University, Stanford, CA (United States)

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

  12. A beam intensity monitor for the Loma Linda cancer therapy proton accelerator

    International Nuclear Information System (INIS)

    A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 1010 and 1011 protons per spill. A beam spill is typically 1 s long with a 2-s repetition period. The intensity monitor must be radiation hard, expose minimum mass to the beam, and measure intensity to 1% in 1-ms time intervals. To this end, a 5-cm-thick xenon gas scintillator optically coupled to a photomultiplier tube (PMT) was tested to measure its response to the proton beam. The gas cell was operated at 1.2 atm of pressure and has 12.7-μm-thick titanium entrance and exit foils. The total mass exposed to the beam is 0.14 g/cm2 and is dominated by the titanium windows. This mass corresponds to a range attenuation equal to 1.4 mm of water. The energy lost to the xenon gas is about 70 keV per proton. Each passing proton will produce approximately 2000 photons. With a detection efficiency on the order of 0.05% for this UV light, one would anticipate over 1010 photoelectrons per second. In a 1-ms time bin there will be approximately 107 photoelectrons. This yields a resolution limited by systematics. For unregulated 0.4-s proton spills, we observe a response bandwidth in excess of 104 Hz. While signal-to-noise and linearity were not easily measured, we estimate as few as 103 protons can be observed suggesting a dynamic range in excess of 105 is available

  13. A beam intensity monitor for the Loma Linda cancer therapy proton accelerator.

    Science.gov (United States)

    Coutrakon, G; Miller, D; Kross, B J; Anderson, D F; DeLuca, P; Siebers, J

    1991-01-01

    A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 10(10) and 10(11) protons per spill. A beam spill is typically 1 s long with a 2-s repetition period. The intensity monitor must be radiation hard, expose minimum mass to the beam, and measure intensity to 1% in 1-ms time intervals. To this end, a 5-cm-thick xenon gas scintillator optically coupled to a photomultiplier tube (PMT) was tested to measure its response to the proton beam. The gas cell was operated at 1.2 atm of pressure and has 12.7-microns-thick titanium entrance and exit foils. The total mass exposed to the beam is 0.14 g/cm2 and is dominated by the titanium windows. This mass corresponds to a range attenuation equal to 1.4 mm of water. The energy lost to the xenon gas is about 70 keV per proton. Each passing proton will produce approximately 2000 photons. With a detection efficiency on the order of 0.05% for this UV light, one would anticipate over 10(10) photoelectrons per second. In a 1-ms time bin there will be approximately 10(7) photoelectrons. This yields a resolution limited by systematics. For unregulated 0.4-s proton spills, we observe a response bandwidth in excess of 10(4) Hz. While signal-to-noise and linearity were not easily measured, we estimate as few as 10(3) protons can be observed suggesting a dynamic range in excess of 10(5) is available. PMID:1656180

  14. Agricultural drought risk monitoring and yield loss forecast with remote sensing data

    Science.gov (United States)

    Nagy, Attila; Tamás, János; Fehér, János

    2015-04-01

    The World Meteorological Organization (WMO) and Global Water Partnership (GWP) have launched a joint Integrated Drought Management Programme (IDMP) to improve monitoring and prevention of droughts. In the frame of this project this study focuses on identification of agricultural drought characteristics and elaborates a monitoring method (with application of remote sensing data), which could result in appropriate early warning of droughts before irreversible yield loss and/or quality degradation occur. The spatial decision supporting system to be developed will help the farmers in reducing drought risk of the different regions by plant specific calibrated drought indexes. The study area was the Tisza River Basin, which is located in Central Europe within the Carpathian Basin. For the investigations normalized difference vegetation index (NDVI) was used calculated from 16 day moving average chlorophyll intensity and biomass quantity data. The results offer concrete identification of remote sensing and GIS data tools for agricultural drought monitoring and forecast, which eventually provides information on physical implementation of drought risk levels. In the first step, we statistically normalized the crop yield maps and the MODIS satellite data. Then the drought-induced crop yield loss values were classified. The crop yield loss data were validated against the regional meteorological drought index values (SPI), the water management and soil physical data. The objective of this method was to determine the congruency of data derived from spectral data and from field measurements. As a result, five drought risk levels were developed to identify the effect of drought on yields: Watch, Early Warning, Warning, Alert and Catastrophe. In the frame of this innovation such a data link and integration, missing from decision process of IDMP, are established, which can facilitate the rapid spatial and temporal monitoring of meteorological, agricultural drought phenomena and its

  15. Performance of a fast acquisition system for in-beam PET monitoring tested with clinical proton beams

    Science.gov (United States)

    Piliero, M. A.; Bisogni, M. G.; Cerello, P.; Del Guerra, A.; Fiorina, E.; Liu, B.; Morrocchi, M.; Pennazio, F.; Pirrone, G.; Wheadon, R.

    2015-12-01

    In this work we present the performance of a fast acquisition system for in-beam PET monitoring during the irradiation of a PMMA phantom with a clinical proton beam. The experimental set-up was based on 4 independent detection modules. Two detection modules were placed at one side of a PMMA phantom and the other two modules were placed at the opposite side of the phantom. One detection module was composed of a Silicon Photon Multiplier produced by AdvanSiD coupled to a single scintillating LYSO crystal. The read-out system was based on the TOFPET ASIC managed by a Xilinx ML605 FPGA Evaluation Board (Virtex 6). The irradiation of the PMMA phantom was performed at the CNAO hadrontherapy facility (Pavia, Italy) with a 95 MeV pulsed proton beam. The pulsed time structure of the proton beam was reconstructed by each detection module. The β+ annihilation peak was successfully measured and the production of β+ isotopes emitters was observed as increasing number of 511 keV events detected during irradiation. Finally, after the irradiation, the half lives of the 11C and 15O radioactive isotopes were estimated.

  16. Monitoring the electron beam position at the TESLA test facility free electron laser

    International Nuclear Information System (INIS)

    The operation of a free electron laser working in the Self Amplified Spontaneous Emission mode (SASE FEL) requires the electron trajectory to be aligned with very high precision in overlap with the photon beam. In order to ensure this overlap, one module of the SASE FEL undulator at the TESLA Test Facility (TTF) is equipped with a new type of waveguide beam position monitor (BPM). Four waveguides are arranged symmetrically around the beam pipe, each channel couples through a small slot to the electromagnetic beam field. The induced signal depends on the beam intensity and on the transverse beam position in terms of beam-to-slot distance. With four slot--waveguide combinations a linear position sensitive signal can be achieved, which is independent of the beam intensity. The signals transduced by the slots are transferred by ridged waveguides through an impedance matching stage into a narrowband receiver tuned to 12 GHz. The present thesis describes design, tests, and implementation of this new type of BPM. (orig.)

  17. Silicon detectors for monitoring neutron beams in n-TOF beamlines.

    Science.gov (United States)

    Cosentino, L; Musumarra, A; Barbagallo, M; Colonna, N; Damone, L; Pappalardo, A; Piscopo, M; Finocchiaro, P

    2015-07-01

    During 2014, the second experimental area (EAR2) was completed at the n-TOF neutron beam facility at CERN (n-TOF indicates neutron beam measurements by means of time of flight technique). The neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target. The resulting neutron beam covers the energy range from thermal to several GeV. In this paper, we describe two beam diagnostic devices, both exploiting silicon detectors coupled with neutron converter foils containing (6)Li. The first one is based on four silicon pads and allows monitoring of the neutron beam flux as a function of the neutron energy. The second one, in beam and based on position sensitive silicon detectors, is intended for the reconstruction of the beam profile, again as a function of the neutron energy. Several electronic setups have been explored in order to overcome the issues related to the gamma flash, namely, a huge pulse present at the start of each neutron bunch which may blind the detectors for some time. The two devices were characterized with radioactive sources and also tested at the n-TOF facility at CERN. The wide energy and intensity range they proved capable of sustaining made them attractive and suitable to be used in both EAR1 and EAR2 n-TOF experimental areas, where they became immediately operational. PMID:26233385

  18. Beam-spot temperature monitoring on the production target at the BigRIPS separator

    International Nuclear Information System (INIS)

    Since 2007, a water-cooled high-power rotating disk target has been in operation at the in-flight radioactive-isotope beam separator (BigRIPS), RIKEN. The target should withstand a goal beam intensity of 1 particle μA (pμA) 238U-beam at 350 AMeV with a spot size of 1 mm in diameter, resulting in a heat deposit of 22 kW in the target. A beam-spot temperature monitoring system using infrared devices in high-radiation environment was elaborately developed. The beam-spot temperature on a beryllium (Be) fixed target and on a rotating Be and tungsten (W) disk target was measured with the most intense beams presently available at our facility. The heat deposit achieved was 0.6 kW, that is 1/37 of the goal value. At the present beam intensity, the result supports our estimation that a water-cooled rotating disk target of 30 cm diameter can withstand an approximately tenfold beam intensity compared to a water-cooled fixed target.

  19. Monitoring the electron beam position at the TESLA test facility free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Kamps, T.

    2000-06-14

    The operation of a free electron laser working in the Self Amplified Spontaneous Emission mode (SASE FEL) requires the electron trajectory to be aligned with very high precision in overlap with the photon beam. In order to ensure this overlap, one module of the SASE FEL undulator at the TESLA Test Facility (TTF) is equipped with a new type of waveguide beam position monitor (BPM). Four waveguides are arranged symmetrically around the beam pipe, each channel couples through a small slot to the electromagnetic beam field. The induced signal depends on the beam intensity and on the transverse beam position in terms of beam-to-slot distance. With four slot--waveguide combinations a linear position sensitive signal can be achieved, which is independent of the beam intensity. The signals transduced by the slots are transferred by ridged waveguides through an impedance matching stage into a narrowband receiver tuned to 12 GHz. The present thesis describes design, tests, and implementation of this new type of BPM. (orig.)

  20. Preliminary beam experiment and parameter simulation for cavity beam position monitor

    International Nuclear Information System (INIS)

    Background: Aiming at precise beam position measurement of next generation FEL facility, Shanghai institute of applied physics developed 5712 MHz high Q CBPM prototype. Purpose: ADC bits and data length of data acquisition system are key parameters influencing spatial resolution of CBPM. In order to find the optimized configuration parameters, dedicated beam experiments and corresponding Monte Carlo simulations were used to solve the problems. Methods: The position calibration factors of CBPM prototype have been obtained through beam based calibration experiment at the Shanghai deep ultraviolet FEL facility. The dependence between system spatial resolution and ADC bits and the data length have been simulated with the measured position calibration factors by using Monte Carlo method. Results: Equipped with 14 bits or better ADCs IF sampling technique is capable to achieve submicron position resolution, which is the optimal choice for CBPM on-line data acquisition system. Applying FFT signal processing algorithm, optimal data lengths in RF and IF sampling techniques were respectively 8192 and 256 points. Conclusions: RF sampling technique is hard to accomplish precise measurement of submicron level due to limited bits of present ultra- high-speed ADC, but suitable for plug and play prototype parameter test and evaluation. (authors)

  1. Monitoring roof beam lateral displacement at the waste isolation pilot plant

    International Nuclear Information System (INIS)

    Lateral displacement in the immediate roof beam at the Waste Isolation Pilot Plant (WIPP) is a significant factor in assessment of excavation performance for the design of ground control systems. Information on roof beam lateral displacement, expansion, fracture formation, as well as excavation convergence, is gathered using a variety of manually and remotely read instruments. Visual observations are also used when possible. This paper describes the methods used to measure lateral displacement, or offset, at the WIPP. Offset magnitudes are determined by the degree of occlusion in drillholes that intersect the offset plane. The Borehole Lateral Displacement Sensor (BLDS) was developed for installation at WIPP to monitor offset at a high degree of accuracy at a short reading frequency. Offset measurements have historically been obtained by visual estimation of borehole occlusion. Use of the BLDS will enable relationships between time dependent roof beam lateral displacement and expansion to be established in much shorter periods than is possible using visual observations. The instrument will also allow remote monitoring of roof beam displacement in areas where visual estimations are not possible. Continued monitoring of roof beam displacement, convergence, and expansion, is integral to timely and pertinent assessments of WIPP excavation performance

  2. Integrating and automating the software environment for the Beam and Radiation Monitoring for CMS

    CERN Document Server

    Filyushkina, Olga; Juslin, J

    2010-01-01

    The real-time online visualization framework used by the Beam and Radiation Monitoring group at the Compact Muon Solenoid at Large Hadron Collider, CERN. The purpose of the visualization framework is to provide real-time diagnostic of beam conditions, which defines the set of the requirements to be met by the framework. Those requirements include data quality assurance, vital safety issues, low latency, data caching, etc. The real-time visualization framework is written in the Java programming language and based on JDataViewer--a plotting package developed at CERN. At the current time the framework is run by the Beam and Radiation Monitoring, Pixel, Tracker groups, Run Field Manager and others. It contributed to real-time data analysis during 2009-2010 runs as a stable monitoring tool. The displays reflect the beam conditions in a real-time with the low latency level, thus it is the first place at the CMS detector where the beam collisions are observed.

  3. Operating results for the beam profile monitor system currently in use at Bevalac Facility

    International Nuclear Information System (INIS)

    Three stations of a soon to be completed multi-station, multi-wire beam monitoring system have been installed in the Bevalac transfer line. The following article will provide a cursory analysis of the electronic circuitry, discuss new design additions and summarize the operating results obtained over the last year

  4. An LHCb general-purpose acquisition board for beam and background monitoring at the LHC

    CERN Document Server

    Alessio, F; Guzik, Z

    2011-01-01

    In this paper we will present an LHCb custom-made acquisition board which was developed for a continuous beam and background monitoring during LHC operations at CERN. The paper describes both the conceptual design and its performance, and concludes with results from the first period of beam operations at the LHC. The main purpose of the acquisition board is to process signals from a pair of beam pickups to continuously monitor the intensity of each bunch, and to monitor the phase of the arrival time of each proton bunch with respect to the LHC bunch clock. The extreme versatility of the board also allowed the LHCb experiment to build a high-speed and high-sensitivity readout system for a fast background monitor based on a pair of plastic scintillators. The board has demonstrated very good performance and proved to be conceptually valid during the first months of operations at the LHC. Connected to the beam pickups, it provides the LHCb experiment with a real-time measurement of the total intensity of each bea...

  5. Two-dimensional beam-profile monitor using the Reticon MC510A array camera

    International Nuclear Information System (INIS)

    A quantitative two-dimensional beam profile may be obtained from a scintillator viewed by a Reticon camera which uses a 32 x 32 array of photodiodes as its sensing element. In this note, CAMAC-oriented data acquisition electronics which allow one either to transmit the profile to a computer, or to use the monitor in a stand-alone mode are described

  6. Beam intensity and dose monitor system for heavy-ion tumor therapy

    International Nuclear Information System (INIS)

    The clinical trials of tumor therapy using heavy ion beams, supplied by the cooler storage ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) with the energy of 100 to 450 MeV/u, are now in progress at the Institute of Modern Physics in Lanzhou. A beam intensity and dose monitor system has been developed to real-time monitor the irradiation dose and beam intensity stability and to make sure the safety of the patients. It is composed of integral ionization chamber, current-frequency transfer electric board and LabVIEW data acquiring and analyzing system. The measurements of this system show that it can work well under the clinical condition. (authors)

  7. A System for Monitoring and Tracking the LHC Beam Spot within the ATLAS High Level Trigger

    CERN Document Server

    Bartoldus, R; The ATLAS collaboration; Cogan, J; Salnikov, A; Strauss, E; Winklmeier, F

    2012-01-01

    The parameters of the beam spot produced by the LHC in the ATLAS interaction region are computed online using the ATLAS High Level Trigger (HLT) system. The high rate of triggered events is exploited to make precise measurements of the position, size and orientation of the luminous region in near real-time, as these parameters change significantly even during a single data-taking run. We present the challenges, solutions and results for the online determination, monitoring and beam spot feedback system in ATLAS. A specially designed algorithm, which uses tracks registered in the silicon detectors to reconstruct event vertices, is executed on the HLT processor farm of several thousand CPU cores. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. The reconstructed beam values are corrected for detector resolution effects, measured in situ from the separation of vertices whose tracks have been split into two collections. Furthermore, measurements for individual ...

  8. Monitoring and Tracking the LHC Beam Spot within the ATLAS High Level Trigger

    CERN Document Server

    Winklmeier, F; The ATLAS collaboration

    2012-01-01

    The parameters of the beam spot produced by the LHC in the ATLAS interaction region are computed online using the ATLAS High Level Trigger (HLT) system. The high rate of triggered events is exploited to make precise measurements of the position, size and orientation of the luminous region in near real-time, as these parameters change significantly even during a single data-taking run. We present the challenges, solutions and results for the online determination, monitoring and beam spot feedback system in ATLAS. A specially designed algorithm, which uses tracks registered in the silicon detectors to reconstruct event vertices, is executed on the HLT processor farm of several thousand CPU cores. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. The reconstructed beam values are corrected for detector resolution effects, measured in situ from the separation of vertices whose tracks have been split into two collections. Furthermore, measurements for individual ...

  9. Diamond pixel detector for beam profile monitoring in COMET experiment at J-PARC

    CERN Document Server

    Cerv, M; Pernegger, H; Vageesvaran, P; Griesmayer, E

    2015-01-01

    We present the design and initial prototype results of a pixellized proton beam profile monitor for the COMET experiment at J-PARC. The goal of COMET is to look for charged lepton flavor violation by direct muon to electron conversion at a sensitivity of $0^{-19}$. An 8 GeV proton beam pulsed at 100 ns with $10^{10}$ protons/s will be used to create muons through pion production and decay. In the final experiment, the proton flux will be raised to $10^{14}$ protons/sec to increase the sensitivity. These requirements of harsh radiation tolerance and fast readout make diamond a good choice for constructing a beam profile monitor in COMET. We present first results of the characterization of single crystal diamond (scCVD) sourced from a new company, 2a systems Singapore. Our measurements indicate excellent charge collection efficiency and high carrier mobility down to cryogenic temperatures.

  10. Capacitive large-range-intensity beam-position monitors at Ganil

    International Nuclear Information System (INIS)

    At GANIL, to allow a permanent measurement of the ion beam position, we are designing a non-interceptive beam position monitor. After having given the technical specifications - in particular a large intensity range 60dB - this paper describes the technical choices of made after theoretical studies: - capacitive electrodes loaded by 50 Ω amplifier, - 10 KHz heterodyne to detect the 2nd harmonic of the electrode signals, - amplitude-to-phase conversion followed by a phasemeter to detect the beam position. At the end of this paper, the first results obtained with a prototype monitor are given, in particular their good accordance with the theoretical calculation and the few problems still to solve

  11. Design and commissioning of the APS beam charge and current monitor

    International Nuclear Information System (INIS)

    The non-intercepting charge and current monitors suitable for a wide range of beam parameters have been developed and installed in the Advanced Photon Source (APS) low energy transport lines, positron accumulator ring (PAR), and injector synchrotron. The positron or electron beam pulse in the APS has charge ranging from 100pC to l0nC with pulse width varying from 30ps to 30ns. The beam charge and current are measured with a current transformer and subsequent current monitoring electronics based on an ultrafast, high precision gated integrator. The signal processing electronics, data acquisition, and communication with the control system are managed by a VME-based system. This paper summarizes the hardware and software features of the systems. The results of recent operations are presented

  12. Dosimetric characteristics of linear accelerator photon beams with small monitor unit settings.

    Science.gov (United States)

    Kang, Sei-Kwon; Cheong, Kwang-Ho; Hwang, Taejin; Cho, Byung Chul; Kim, Su Ssan; Kim, Kyoung Ju; Oh, Do Hoon; Bae, Hoonsik; Suh, Tae-Suk

    2008-11-01

    Several studies on the effect of tumor cell killing by dose rate variation have implied that the use of a shorter treatment time is more favorable for intensity modulated radiation therapy (IMRT). Aiming at step-and-shoot IMRT with higher dose rates, the stabilities of beam output and profiles with small monitor unit (MU) settings were investigated for various dose rates. With the use of a Varian 21EX (Varian Medical Systems Inc., Palo Alto, CA), static and step-and-shoot IMRT beam output along with profiles were measured by use of an ion chamber and a two-dimensional diode array detector as a function of monitor units and dose rates. For a static case, as the MU approached 1, the beam output increased up to 2% for 300 MU/min and 4.5% for 600 MU/min, showing a larger overdose as the dose rate increased. Deterioration of the beam symmetry and flatness were also observed as the MU decreased to 1 monitor unit. For the step-and-shoot IMRT case, a large dosimetric error of more than 10% was also detected with the use of a small MU segment. However, no definite correlation with the dose rate was observed due to the combined beam start-up effects by the grid pulse and finite communication time between the machine console and multileaf collimator (MLC) controller. For step-and-shoot IMRT with higher dose rates, beam output and beam profile stability with small MU needs to be checked, and adequate MU limitation where segments are not allowed need to be reflected in the step-and-shoot IMRT planning. PMID:19070251

  13. Final report on fiscal year 1992 activities for the environmental monitors line-loss study

    International Nuclear Information System (INIS)

    The work performed on this Environmental Monitors Line-Loss Study has been performed under Contract Numbers MLW-SVV-073750 and MFH-SVV-207554. Work on the task was initiated mid-December 1991, and this report documents and summarizes the work performed through January 18, 1993. The sections included in this report summarize the work performed on the Environmental Monitors Line-Loss Study. The sections included in this report are arranged to reflect individual sub-tasks and include: descriptions of measurement systems and procedures used to obtain cascade impactor samples and laser spectrometer measurements from multiple stacks and locations; information on data acquisition, analyses, assessment, and software; discussion of the analyses and measurement results from the cascade impactor and laser spectrometer systems and software used; discussion on the development of general test methods and procedures for line-loss determinations; an overall summary and specific conclusions that can be made with regard to efforts performed on this task during FY 1992 and FY 1993. Supporting information for these sections is included in this report as appendices

  14. GATE simulation based feasibility studies of in-beam PET monitoring in 12C beam cancer therapy

    Institute of Scientific and Technical Information of China (English)

    WU Jing; LIU Yaqiang; MA Tianyu; WEI Qingyang; WANG Shi; CHENG Jianping

    2010-01-01

    In comparison with conventional radiotherapy techniques,12C beam therapy has its significant advantage in cancer treatment because the radiation dose are mostly concentrated near the Bragg peak region and damage to normal tissues along the beam path is thus greatly reduced.In-beam PET provides a way to monitor dose distribution inside human body since several kinds of positron-emitting nuclei are produced through the interaction between 12C beam and body matters.In this work,we study the quantitative relationship between the spatial location of the Bragg peak and the spatial distribution of positrons produced by positron-emitting nuclei.Monte Carlo package GATE is used to simulate the interactions between the incident 12C beam of different energies (337.5,270.0 and 195.0 MeV/u) and various target matters (water,muscle and spine bone).Several data post-processing operations are performed on the simulated positron-emitting nuclei distribution data to mimic the impacts of positron generation and finite spatial resolution of a typical PET imaging system.Simulation results are compared to published experimental data for verification.In all the simulation cases,we fred that 10C and 11C are two dominant positron-emitting nuclei,and there exists a significant correlation between the spatial distributions of deposited energy and positrons.Therefore,we conclude that it is possible to determine the location of Bragg peak with 1 mm accuracy using current PET imaging systems by detecting the falling edge of the positron distribution map in depth direction.

  15. GATE simulation based feasibility studies of in-beam PET monitoring in 12C beam cancer therapy

    International Nuclear Information System (INIS)

    In comparison with conventional radiotherapy techniques, 12C beam therapy has its significant advantage in cancer treatment because the radiation dose are mostly concentrated near the Bragg peak region and damage to normal tissues along the beam path is thus greatly reduced. In-beam PET provides a way to monitor dose distribution inside human body since several kinds of positron-emitting nuclei are produced through the interaction between 12C beam and body matters. In this work, we study the quantitative relationship between the spatial location of the Bragg peak and the spatial distribution of positrons produced by positron-emitting nuclei. Monte Carlo package GATE is used to simulate the interactions between the incident 12C beam of different energies (337.5, 270.0 and 195.0 MeV/u) and various target matters (water, muscle and spine bone). Several data post-processing operations are performed on the simulated positron-emitting nuclei distribution data to mimic the impacts of positron generation and finite spatial resolution of a typical PET imaging system. Simulation results are compared to published experimental data for verification. In all the simulation cases, we find that 10C and 11C are two dominant positron-emitting nuclei, and there exists a significant correlation between the spatial distributions of deposited energy and positrons. Therefore, we conclude that it is possible to determine the location of Bragg peak with 1 mm accuracy using current PET imaging systems by detecting the falling edge of the positron distribution map in depth direction. (authors)

  16. Construction of the beam profile monitor system with CameraLink in the SPring-8 booster ring and beam transport line

    International Nuclear Information System (INIS)

    We had measured the beam position and size in the SPring-8 booster ring and beam transport line by the monitor system that consists of analog video camera and fluorescent plate. It was difficult to estimate the seasonal change of the beam position and beam size between user operation cycles. In order to keep the high injection efficiency to SPring-8 storage ring, we need to achieve the tuning reproducibility of the accelerator parameter in the booster ring and beam transport line by using the quantitative data. The newly constructed beam profile monitor system consists of the digital CCD camera with external trigger synchronous capturing function, camera selectors, and server computers. Each camera system placed on the booster ring and beam transport line are managed by the UNIX server computer setup for each area. This system is connected by the cameralink configuration devices with cameralink cables or optical fiber cables. It became possible to capture image of beam profile synchronous with a beam trigger with a high resolution and a fast capturing time as same as it by using the analog video system. We will report the detail of beam profile monitor system with cameralink and the system operation. (author)

  17. On-line neutron beam monitoring of the Finnish BNCT facility

    International Nuclear Information System (INIS)

    A Boron Neutron Capture Therapy (BNCT) facility has been built at the FiR 1 research reactor of VTT Chemical Technology in Espoo, Finland. The facility is currently undergoing dosimetry characterisation and neutron beam operation research for clinical trials. The healthy tissue tolerance study, which was carried out in the new facility during spring 1998, demonstrated the reliability and user-friendliness of the new on-line beam monitoring system designed and constructed for BNCT by VTT Chemical Technology. The epithermal neutron beam is monitored at a bismuth gamma shield after an aluminiumfluoride-aluminium moderator. The detectors are three pulse mode U235-fission chambers for epithermal neutron fluence rate and one current mode ionisation chamber for gamma dose rate. By using different detector sensitivities the beam intensity can be measured over a wide range of reactor power levels (0.001-250 kW). The detector signals are monitored on-line with a virtual instrumentation (LabView) based PC-program, which records and displays the actual count rates and total counts of the detectors in the beam. Also reactor in-core power instrumentation and control rod positions can be monitored via another LabView application. The main purpose of the monitoring system is to provide a dosimetric link to the dose in a patient during the treatment, as the fission chamber count rates have been calibrated to the induced thermal neutron fluence rate and to the absorbed dose rate at reference conditions in a tissue substitute phantom

  18. On-line neutron beam monitoring of the Finnish BNCT facility

    Science.gov (United States)

    Tanner, Vesa; Auterinen, Iiro; Helin, Jori; Kosunen, Antti; Savolainen, Sauli

    1999-02-01

    A Boron Neutron Capture Therapy (BNCT) facility has been built at the FiR 1 research reactor of VTT Chemical Technology in Espoo, Finland. The facility is currently undergoing dosimetry characterisation and neutron beam operation research for clinical trials. The healthy tissue tolerance study, which was carried out in the new facility during spring 1998, demonstrated the reliability and user-friendliness of the new on-line beam monitoring system designed and constructed for BNCT by VTT Chemical Technology. The epithermal neutron beam is monitored at a bismuth gamma shield after an aluminiumfluoride-aluminium moderator. The detectors are three pulse mode U 235-fission chambers for epithermal neutron fluence rate and one current mode ionisation chamber for gamma dose rate. By using different detector sensitivities the beam intensity can be measured over a wide range of reactor power levels (0.001-250 kW). The detector signals are monitored on-line with a virtual instrumentation (LabView) based PC-program, which records and displays the actual count rates and total counts of the detectors in the beam. Also reactor in-core power instrumentation and control rod positions can be monitored via another LabView application. The main purpose of the monitoring system is to provide a dosimetric link to the dose in a patient during the treatment, as the fission chamber count rates have been calibrated to the induced thermal neutron fluence rate and to the absorbed dose rate at reference conditions in a tissue substitute phantom.

  19. Test Results on the Silicon Pixel Detector for the TTF-FEL Beam Trajectory Monitor

    CERN Document Server

    Hillert, S; Müller, U C; Roth, S; Hansen, K; Holl, P; Karstensen, S; Kemmer, J; Klanner, Robert; Lechner, P; Leenen, M; Ng, J S T; Schmüser, P; Strüder, L

    2001-01-01

    Test measurements on the silicon pixel detector for the beam trajectory monitor at the free electron laser of the TESLA test facility are presented. To determine the electronic noise of detector and read-out and to calibrate the signal amplitude of different pixels the 6 keV photons of the manganese K line are used. Two different methods determine the spatial accuracy of the detector: In one setup a laser beam is focused to a straight line and moved across the pixel structure. In the other the detector is scanned using a low-intensity electron beam of an electron microscope. Both methods show that the symmetry axis of the detector defines a straight line within 0.4 microns. The sensitivity of the detector to low energy X-rays is measured using a vacuum ultraviolet beam at the synchrotron light source HASYLAB. Additionally, the electron microscope is used to study the radiation hardness of the detector.

  20. Electromagnetic Coupling Between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System

    CERN Document Server

    Andreazza, W; Bravin, E; Caspers, F; Garlasch`e, M; Gras, J; Goldblatt, A; Lefevre, T; Jones, R; Metral, E; Nosych, A; Roncarolo_, F; Salvant, B; Trad, G; Veness, R; Vollinger, C; Wendt, M

    2013-01-01

    The CERN LHC is equipped with two Synchrotron Radiation Monitor (BSRT) systems used to characterise transverse and longitudinal beam distributions. Since the end of the 2011 LHC run the light extraction system, based on a retractable mirror, has suffered deformation and mechanical failure that is correlated to the increase in beam intensity. Temperature probes have associated these observations to a strong heating of the mirror support with a dependence on the longitudinal bunch length and shape, indicating the origin as electromagnetic coupling between the beam and the structure. This paper combines all this information with the aim of characterising and improving the system in view of its upgrade during the current LHC shutdown. Beam-based observations are presented along with electromagnetic and thermomechanical simulations and complemented by laboratory measurements, including the study of the RF properties of different mirror bulk and coating materials.

  1. A Four Channel Beam Current Monitor Data Acquisition System Using Embedded Processors

    Energy Technology Data Exchange (ETDEWEB)

    Wheat, Jr., Robert Mitchell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalmas, Dale A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-11

    Data acquisition from multiple beam current monitors is required for electron accelerator production of Mo-99. A two channel system capable of recording data from two beam current monitors has been developed, is currently in use, and is discussed below. The development of a cost-effective method of extending this system to more than two channels and integrating of these measurements into an accelerator control system is the main focus of this report. Data from these current monitors is digitized, processed, and stored by a digital data acquisition system. Limitations and drawbacks with the currently deployed digital data acquisition system have been identified as have been potential solutions, or at least improvements, to these problems. This report will discuss and document the efforts we've made in improving the flexibility and lowering the cost of the data acquisition system while maintaining the minimum requirements.

  2. Profile distortion by beam space-charge in Ionization Profile Monitors

    CERN Document Server

    Vilsmeier, D; Wettig, T

    Measuring the transverse beam size in the Large Hadron Collider by using Ionization Profile Monitors is a difficult task for energies above injection during the energy ramp from 450 GeV to 6.5TeV. The beam size decreases from around 1mm to 200um and the brightness of the beam is high enough to destroy the structure of any form of interacting matter. While the electron trajectories are confined by an external electro-magnetic field which forces the electrons accordingly on helix paths with certain gyroradii, this gyration is heavily increased under the influence of the electric field of the beam. Smaller beam sizes, which go hand in hand with increased bunch electric fields, lead to larger gyroradii of the ionized electrons, which results in strongly distorted profiles. In addition, this distortion becomes more visible for smaller beam sizes as the extent of gyration grows compared to the actual beam size. Depending on the initial momentum distribution of the electrons, emerging from the ionization process wit...

  3. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Polarisation splitting of laser beams by large angles with minimal reflection losses

    Science.gov (United States)

    Davydov, B. L.

    2006-05-01

    New crystal anisotropic prisms for splitting orthogonally polarised components of laser radiation by large angles with minimal reflection losses caused by the Brewster refraction and total internal reflection of polarised waves from the crystal—air interface are considered and the method for their calculation is described. It is shown that, by assembling glue-free combinations of two or three prisms, thermally stable beamsplitters can be fabricated, which are free from the beam astigmatism and the wave dispersion of the output angles of the beams. The parameters and properties of new beamsplitters are presented in a convenient form in figures and tables.

  4. High performance quantum cascade lasers: Loss, beam stability, and gain engineering

    Science.gov (United States)

    Bouzi, Pierre Michel

    Quantum Cascade (QC) lasers are semiconductor devices emitting in the mid-infrared (3-30 micron) and terahertz (30-300 micron) regions of the electromagnetic spectrum. Since their first demonstration by Jerome Faist et. al. in 1994, they have evolved very quickly into high performance devices and given rise to many applications such as trace-gas sensing, medical diagnosis, free-space communication, and light detection and ranging (LIDAR). In this thesis, we investigate a further increase of the performance of QC devices and, through meticulous device modeling and characterizations, gain a deeper understanding of several of their unique characteristics, especially their carrier transport and lifetime, their characteristic temperature, their waveguide loss and modal gain, their leakage current, and their transverse mode profile. First, in our quest to achieve higher performance, we investigate the effect of growth asymmetries on device transport characteristics. This investigation stems from recent studies on the role of interface roughness on intersubband scattering and device performance. Through a symmetric active core design, we find that interface roughness and ionized impurity scattering induced by dopant migration play a significant role in carrier transport through the device. Understanding how interface roughness affects intersubband scattering, in turn, we engineer the gain in QC devices by placing monolayer barriers at specific locations within the device band structure. These strategically placed additional thin barrier layers introduce roughness scattering into the device active region, thereby selectively decreasing the lower laser state lifetime and increasing population inversion necessary for laser action. Preliminary measurement results from modified devices reveal a 50% decrease in the emission broadening compared to the control structures, which should lead to a two-fold increase in gain. A special class of so-called "strong coupling" QC lasers

  5. Optical beam profile monitor and residual gas fluorescence at the relativistic heavy ion collider polarized hydrogen jet.

    Science.gov (United States)

    Tsang, T; Bellavia, S; Connolly, R; Gassner, D; Makdisi, Y; Russo, T; Thieberger, P; Trbojevic, D; Zelenski, A

    2008-10-01

    A gas fluorescence beam profile monitor has been implemented at the relativistic heavy ion collider (RHIC) using the polarized atomic hydrogen gas jet, which is part of the polarized proton polarimeter. RHIC proton beam profiles in the vertical plane of the accelerator are obtained as well as measurements of the width of the gas jet in the beam direction. For gold ion beams, the fluorescence cross section is sufficiently large so that profiles can be obtained from the residual gas alone, albeit with long light integration times. We estimate the fluorescence cross sections that were not known in this ultrarelativistic regime and calculate the beam emittance to provide an independent measurement of the RHIC beam. This optical beam diagnostic technique, utilizing the beam induced fluorescence from injected or residual gas, offers a noninvasive particle beam characterization and provides visual observation of proton and heavy ion beams. PMID:19044742

  6. Smart x-ray beam position monitor system for the Advanced Photon Source

    International Nuclear Information System (INIS)

    In third-generation synchrotron radiation sources, such as the Advanced Photon Source (APS), the sensitivity and reliability requirements for the x-ray beam position monitors (XBPMs) are much higher than for earlier systems. Noise and contamination signals caused by radiation emitted from the bending magnet become a major problem. The regular XBPM calibration process can only provide signal correction for one set of conditions for the insertion devices (ID). During normal operation, parameters affecting the ID-emitted beam, such as the gap of the ID magnets and the beam current, are the variables. A new smart x-ray beam position monitor system (SBPM) has been conceived and designed for the APS. It has a built in self-learning structure with EEPROM memory that is large enough to open-quote open-quote remember close-quote close-quote a complete set of calibration data covering all the possible operating conditions. During the self-learning mode, the monitor system initializes a series of automatic scan motions with information for different ID setups and records them into the database array. During normal operation, the SBPM corrects the normalized output according to the ID setup information and the calibration database. So that, with this novel system, the SBPM is always calibrating itself with the changing ID set up conditions. copyright 1996 American Institute of Physics

  7. Characterization of a thermal neutron beam monitor based on gas electron multiplier technology

    Science.gov (United States)

    Croci, Gabriele; Cazzaniga, Carlo; Claps, Gerardo; Tardocchi, Marco; Rebai, Marica; Murtas, Fabrizio; Vassallo, Espedito; Caniello, Roberto; Cippo, Enrico Perelli; Grosso, Giovanni; Rigato, Valentino; Gorini, Giuseppe

    2014-08-01

    Research into valid alternatives to 3He detectors is fundamental to the affordability of new neutron spallation sources like the European Spallation Source (ESS). In the case of ESS it is also essential to develop high-rate detectors that can fully exploit the increase of neutron flux relative to present neutron sources. One of the technologies fulfilling these requirements is the gas electron multiplier (GEM), since it can combine a high rate capability (MHz/mm2), a coverage area up to 1 m2 and a space resolution better than 0.5 mm. Its use as a neutron detector requires conversion of neutrons into charged particles. This paper describes the realization and characterization of a thermal neutron GEM-based beam monitor equipped with a cathode containing ^{10}B for neutron conversion. This device is constituted by a triple GEM detector whose cathode is made of an aluminum sheet covered by a 1 μ m thick ^{{nat}}B4C layer. The method used to realize a long-lasting ^{{nat}}B4C layer is described and the properties of such a layer have been determined. The detector performances (measured on the ISIS-VESUVIO beam line) in terms of beam profile reconstruction, imaging, and measurement of the thermal neutron beam energy spectrum are compatible with those obtained by standard beam monitors.

  8. Test Results on the Silicon Pixel Detector for the TTF-FEL Beam Trajectory Monitor

    OpenAIRE

    Hillert, S.; Ischebeck, R.; Müller, U. C.; Roth, S.; Hansen, K.; Holl, P.; Karstensen, S.; Kemmer, J.; Klanner, R.; Lechner, P.; Leenen, M; Ng, J. S. T.; Schmüser, P.; Strüder, L.

    2000-01-01

    Test measurements on the silicon pixel detector for the beam trajectory monitor at the free electron laser of the TESLA test facility are presented. To determine the electronic noise of detector and read-out and to calibrate the signal amplitude of different pixels the 6 keV photons of the manganese K line are used. Two different methods determine the spatial accuracy of the detector: In one setup a laser beam is focused to a straight line and moved across the pixel structure. In the other th...

  9. Online monitoring of beam phase and intensity using lock-in amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, R., E-mail: rkoyama@riken.jp [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); SHI Accelerator Service Ltd., 1-17-6 Ohsaki, Shinagawa, Tokyo 141-0032 (Japan); Sakamoto, N.; Fujimaki, M.; Fukunishi, N.; Goto, A.; Hemmi, M.; Kase, M.; Suda, K.; Watanabe, T.; Yamada, K.; Kamigaito, O. [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2013-11-21

    We have developed a monitoring system dedicated for heavy-ion cyclotrons that incorporates lock-in amplifiers (LIAs) that can measure the beam phase of signals from phase probe with an amplitude of a few hundred nanovolts. We have compared the performance of the LIA system with that of a conventional system that incorporates oscilloscopes (OSCs). It was confirmed that the LIA system has a much higher precision than the OSC system by the measurement with a wide dynamic range of beam current. Isochronism measurements for a ring cyclotron with a low velocity gain (1.5) were made using both systems and excellent agreement was found between them. However there was a discrepancy between the beam phase measurements using the OSC system and the LIA system, for the case of a ring cyclotron with a high velocity gain of 4.0. It turned out due to a large radial variation of the phase width of circulating beam bunch according to a radial distribution of the acceleration voltage. It was also confirmed that the cable dispersion disturbs the beam-phase measurement using OSC system. -- Highlights: •We have developed a beam monitoring system using lock-in amplifiers (LIAs). •LIA can measure the signal as small as 200 nV corresponds to 10 enA of beam current. •LIA has higher phase resolution (=0.02°) than the conventional oscilloscope system. •LIA system has contributed to the stability improvement of cyclotron-facility RIBF. •Disturbance of cable dispersion to the isochronism measurement was confirmed.

  10. Online monitoring of beam phase and intensity using lock-in amplifiers

    International Nuclear Information System (INIS)

    We have developed a monitoring system dedicated for heavy-ion cyclotrons that incorporates lock-in amplifiers (LIAs) that can measure the beam phase of signals from phase probe with an amplitude of a few hundred nanovolts. We have compared the performance of the LIA system with that of a conventional system that incorporates oscilloscopes (OSCs). It was confirmed that the LIA system has a much higher precision than the OSC system by the measurement with a wide dynamic range of beam current. Isochronism measurements for a ring cyclotron with a low velocity gain (1.5) were made using both systems and excellent agreement was found between them. However there was a discrepancy between the beam phase measurements using the OSC system and the LIA system, for the case of a ring cyclotron with a high velocity gain of 4.0. It turned out due to a large radial variation of the phase width of circulating beam bunch according to a radial distribution of the acceleration voltage. It was also confirmed that the cable dispersion disturbs the beam-phase measurement using OSC system. -- Highlights: •We have developed a beam monitoring system using lock-in amplifiers (LIAs). •LIA can measure the signal as small as 200 nV corresponds to 10 enA of beam current. •LIA has higher phase resolution (=0.02°) than the conventional oscilloscope system. •LIA system has contributed to the stability improvement of cyclotron-facility RIBF. •Disturbance of cable dispersion to the isochronism measurement was confirmed

  11. Microcontroller based four-channel current readout unit for beam slit monitor

    International Nuclear Information System (INIS)

    This paper describes the design and development of a microcontroller based four-channel current readout unit for Beam Slit Monitor (BSM) installed in Transport Line-1 of Indus Accelerator Complex. BSM is a diagnostic device consisting of two horizontal and two vertical blades, which can be moved independently in to the beam pipe to cut the beam transversely. The readout unit employs switched integrators with reset, hold and select switches and timing and control unit. It integrates the current output of the four blades of BSM and produces an output corresponding to the beam charge intercepted by the blade. The integrator outputs are then multiplexed and digitized using 12-bit ADC. Acquired digital data from ADC is stored into on-chip RAM of the microcontroller. The readout sequence is synchronized with the Microtron beam-timing signal. The timing of integration, hold and reset cycles is controlled by the microcontroller. The unit is connected on a serial link to the host computer in main control room. This unit has been integrated with the BSM system and is being used to obtain the electron beam profile. (author)

  12. Mitigation of coherent-OTR light effect for the beam profile monitor of SACLA

    International Nuclear Information System (INIS)

    A screen monitor (SCM) system for SACLA has been developed and was installed in order to obtain a direct image of a transverse beam profile. The taken image has a spatial resolution of about 10 μm, which is required to investigate electron-beam properties, such as a beam emittance. The SCM takes an image of the beam profile by a CCD camera with a customized optical system through an OTR radiation from a stainless steel screen. At the beginning of SACLA operation, strong coherent OTR (COTR), which made an incorrect beam profile, was observed. In COTR light, light intensity and an imaging with a speckle widely fluctuate in every shot. In order to suppress the COTR on the SCM, the stainless steel target was replaced to a Ce:YAG scintillation target. Since the COTR was still generated from the Ce:YAG target, a spatial mask was employed. The mask was mounted on the center of an optical axis of the SCM, because the COTR light is emitted forward within ∼1/γ radian from the screen to the CCD, while scintillation light does not have angular dependence. Hence the mask obstructs the COTR light to the CCD. Clear beam profiles with a diameter of a few tens of micro-meter are observed by means of the SCMs with this simple improvement. This fact indirectly testifies the SCM has a spatial resolution of about 10 μm. (author)

  13. BEAM-LOSS DRIVEN DESIGN OPTIMIZATION FOR THE SPALLATION NEUTRON SOURCE (SNS) RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; CAMERON,P.; DANBY,G.; GARDNER,C.J.; JACKSON,J.; LEE,Y.Y.; LUDEWIG,H.; MALITSKY,N.; RAPARIA,D.; TSOUPAS,N.; WENG,W.T.; ZHANG,S.Y.

    1999-03-29

    This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).

  14. Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals

    CERN Document Server

    Batarin, V A; Davidenko, A M; Derevshchikov, A A; Goncharenko, Yu M; Grishin, V N; Kachanov, V A; Konstantinov, A S; Kravtsov, V I; Kubota, Y; Lukanin, V S; Matulenko, Yu A; Melnik, Yu M; Meshchanin, A P; Mikhalin, N E; Minaev, N G; Mochalov, V V; Morozov, D A; Nogach, L V; Ryazantsev, A V; Semenov, P A; Semenov, V K; Shestermanov, K E; Soloviev, L F; Stone, S; Uzunian, A V; Vasilev, A N; Yakutin, A E; Yarba, J V

    2005-01-01

    Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.

  15. Development of Ribbon Fiber Type Multi-Channel Power Level Monitor with Low-Insertion/Polarization Loss

    Institute of Scientific and Technical Information of China (English)

    Maki Inai; Akira Haraguchi; Takeo Komiya; Kiyotaka Murashima; Takashi Sasaki; Kazuhito Saitoh

    2003-01-01

    We would like to propose a new in-line multi-channel power level monitor, which is applicable as tap-monitor for multi-channel WDM signals. Its ribbon fiber structure has far exceeded PLC performance and realized compact-size and lower insertion/polarization dependent loss.

  16. Progress of the APS high heat load X-ray beam position monitor development

    International Nuclear Information System (INIS)

    Several novel design developments have been established for the Advanced Photon Source (APS) insertion device (ID) X-ray beam position monitor (XBPM) to improve its performance: (1) optimized geometric configuration of the monitor's sensory blades; (2) smart XBPM system with an intelligent digital signal processor, which provides a self-learning and calibration function; and (3) transmitting XBPM with prefiltering in the commissioning windows for the front end. In this write-up, the authors summarize the recent progress on the XBPM development for the APS ID front ends

  17. Progress of the APS high heat load x-ray beam position monitor development

    International Nuclear Information System (INIS)

    Several novel design developments have been established for the Advanced Photon Source (APS) insertion device (ID) X-ray beam position monitor (XBPM) to improve its performance: - optimized geometric configuration of the monitor's sensory blades; - smart XBPM system with an intelligent digital signal processor, which provides a self-learning and calibration function; and - Transmitting XBPM with prefiltering in the commissioning windows for the front end. In this write-up, we summarize the recent progress on the XBPM development for the APS ID front ends

  18. Resolution power of residual gas ionization monitors for proton beams at PETRA and HERA

    International Nuclear Information System (INIS)

    Residual gas ionisation monitors are used at DESY to measure emittances and profiles of proton beams. Multi channel plates are used as image itensifiers and video cameras are used to obsere the outcoming signals. The accuracy of this method is investigated. The influence of the space charge field of the proton bunches on the motion of ions within the monitors and instrumental effects on the obsered profile are surveyed. Theoretical calculations and Monte Carlo simulations are used to determine correction functions for these effects. The influence of the micro channel plates, optical systems and the video cameras on the obsered signals are also examined. (orig./HP)

  19. X-ray beam monitor using a transmission-type PIN photodiode

    International Nuclear Information System (INIS)

    A new transmission-type PD has been tested in its dynamic range and in accuracy for obtaining input photon rates. At 7.30 keV, the linearity reached 108 of the input photon rate. The error for input photon rates was less than 10% even at near 1012 photons/s. These results show that the PD detector is suitable for a beam monitor for synchrotron radiation X-rays. However, the absorption of 0.415 in the diode itself might be too large. At higher energies, the detector is useful even for the transmission set-up. We are now preparing some experiments to prove availability for higher energies. While we did not find the limitation of input photon rate and the effect of radiation damage for the device, these will be tested for the application of the beam monitor. (author)

  20. A fast profile monitor with scintillating fiber hodoscopes for high-intensity photon beams

    Science.gov (United States)

    Ishikawa, T.; Fujimura, H.; Hamano, H.; Hashimoto, R.; Honda, Y.; Ishida, T.; Kaida, S.; Kanda, H.; Kido, S.; Matsumura, Y.; Miyabe, M.; Mizutani, K.; Nagasawa, I.; Nakamura, A.; Nanbu, K.; Nawa, K.; Ogushi, S.; Shibasaki, Y.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, K.; Takahashi, S.; Taniguchi, Y.; Tokiyasu, A. O.; Tsuchikawa, Y.; Yamazaki, H.

    2016-03-01

    A fast beam-profile monitor has been developed for high-energy photon beamlines at the Research Center for Electron Photon Science, Tohoku University. The position of the photon converted into an electron-positron pair in a 0.5 mm-thick aluminum plate is measured with two hodoscopes made of scintillating fibers with cross-sections of 3 × 3mm2. Events in which charged particles are produced upstream are rejected with a charge veto plastic scintillator placed in front of the plate, and pair-production events are identified with a trigger plastic scintillator placed behind the plate. The position is determined by a developed logic module with a field-programmable gate array. The dead time for processing an event is 35 ns, and a high data acquisition efficiency (~ 100 %) can be achieved with this monitor for high-intensity photon beams corresponding to 20 MHz tagging signals.

  1. A LVDT conditioner for the beam profile monitors of the AmPS

    International Nuclear Information System (INIS)

    A LVDT (Linear Variable Differential Transformer) is a transducer for localization. Because of its applied materials, its construction and the absence of bearings etc. the instrument is suitable to be applied in locations where radioactive radiation is present. In order to obtain information about the position of the iron core in the transducer, a conditioner is needed. In 1977 by Digel a conditioner has been developed for the beam profile monitors (moving wire) of MEA because the 'market' could not meet the requirements then. Nowadays the 'market' offers i.c.'s which can take over the work of the Eurocard developed then. Digel has investigated them in order to see if they are applicable for the beam profile monitors of AmPS. (author). 5 refs.; 7 figs.; 13 tabs

  2. Parallel plate chambers for monitoring the profiles of high-intensity pulsed antiproton beams

    CERN Document Server

    Hori, Masaki

    2004-01-01

    Two types of beam profile monitor with thin parallel-plate electrodes have been used in experiments carried out at the Low Energy Antiproton Ring (LEAR) and Antiproton Decelerator (AD) of CERN. The detectors were used to measure non-destructively the spatial profiles, absolute intensities, and time structures of 100-300-ns- long beam pulses containing between 10**7 and 10**9 antiprotons. The first of these monitors was a parallel plate ionization chamber operated at gas pressure P=65 mbar. The other was a secondary electron emission detector, and was operated in the ultra-high vacuum of the AD. Both designs may be useful in medical and commercial applications. The position-sensitive electrodes in these detectors were manufactured by a novel method in which a laser trimmer was used to cut strip patterns on metallized polyester foils.

  3. Beam-based monitoring of the SLC linac optics with a diagnostic pulse

    International Nuclear Information System (INIS)

    The beam optics in a linear accelerator may be changed significantly by variations in the energy and energy spread profile along the linac. In particular, diurnal temperature swings in the SLC klystron gallery perturb the phase and amplitude of the accelerating RF fields. If such changes are not correctly characterized, the resulting errors will cause phase advance differences in the beam optics. In addition RF phase errors also affect the amplitude growth of betatron oscillations. The authors present an automated, simple procedure to monitor the beam optics in the SLC linac routinely and non-invasively. The measured phase advance and oscillation amplitude is shown as a function of time and is compared to the nominal optics

  4. LUMINESCENCE BEAM PROFILE MONITOR FOR THE RHIC POLARIZED HYDROGEN JET POLARIMETER.

    Energy Technology Data Exchange (ETDEWEB)

    LUCIANO, N.; NASS, A.; MAKDISI, Y.; THIEBERGER, P.; TRBOJEVIC, D.; ZELENSKI, A.

    2005-05-16

    A new polarized hydrogen jet target was used to provide improved beam polarization measurements during the second polarized proton m in the Relativistic Heavy Ion Collider (RHIC). The luminescence produced by beam-hydrogen excitations was also used to test the feasibility of a new beam profile monitor for RFPIC based on the detection of the emitted light. Lenses, a view-port and a sensitive CCD camera were added to the system to record the optical signals from the interaction chamber. The first very promising results are reported here. The same system with an additional optical spectrometer or optical filter system may be used in the future to detect impurities in the jet, such as oxygen molecules, which affect the accuracy of the polarization measurements.

  5. Cavity beam position monitor system for the Accelerator Test Facility 2

    CERN Document Server

    Kim, Y I; Aryshev, A; Boogert, S T; Boorman, G; Frisch, J; Heo, A; Honda, Y; Hwang, W H; Huang, J Y; Kim, E -S; Kim, S H; Lyapin, A; Naito, T; May, J; McCormick, D; Mellor, R E; Molloy, S; Nelson, J; Park, S J; Park, Y J; Ross, M; Shin, S; Swinson, C; Smith, T; Terunuma, N; Tauchi, T; Urakawa, J; White, G R

    2013-01-01

    The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. This paper describes the high resolution cavity beam position monitor (BPM) system, which is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.423 GHz, and S-band at 2.888 GHz with an increased beam aperture. The cavities, electronics, and digital processing are described. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1 m for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm.

  6. Beam profile measurement of ES-200 using secondary electron emission monitor

    Directory of Open Access Journals (Sweden)

    E Ebrahimi Basabi

    2015-09-01

    Full Text Available Up to now, different designs have been introduced for measurement beam profile accelerators. Secondary electron emission monitors (SEM are one of these devices which have been used for this purpose. In this work, a SEM has been constructed to measure beam profile of ES-200 accelerator, a proton electrostatic accelerator which is installed at SBU. Profile grid for both planes designed with 16 wires which are insulated relative to each other. The particles with maximum energy of 200 keV and maximum current of 400 μA are stopped in copper wires. Each of the wires has an individual current-to-voltage amplifier. With a multiplexer, the analogue values are transported to an ADC. The ADCs are read out by a microcontroller and finally profile of beam shows by a user interface program

  7. Button-type beam-position monitor for the ATF damping ring

    International Nuclear Information System (INIS)

    Button-type beam-position monitors (BPMs) were fabricated for the ATF damping ring. The BPM was designed to achieve a position resolution of less than 5 μm; fabrication of the first 40 BPMs has been completed. For this BPM, a beam test was carried out at the 80-MeV injector part of the ATF LINAC. All of the bunch signals in the multi-bunch beam were clearly observed without any discharge. A calibration of the BPMs was also performed in order to check their offset from the electrical center to the mechanical center as well as their position detection sensitivity. The result shows good uniformity in position detection. (author)

  8. A bunch-by-bunch beam position monitor based on scope embedded IOC

    International Nuclear Information System (INIS)

    A bunch-by-bunch beam position monitor system, based on a broadband oscilloscope embedded EPICS IOC, has been developed at SSRF to study the beam instabilities driven by the wake-field effects. The horizontal and vertical beam positions of each bunch could be located independently in this system by using the original signals from the button-type pickups on the storage ring. In this article, we report the hardware and software architecture of this system. The bunch-by-bunch data of the storage ring are used to evaluate performance of the system. Dependency of the tune, and the betatron oscillation amplitude of different bunch on the corresponding bunch ID, is also detected. The system is an effective tool for machine-study of SSRF. (authors)

  9. Flow sensing by buckling monitoring of electrothermally actuated double-clamped micro beams

    CERN Document Server

    Kessler, Yoav; Liberzon, Alex

    2016-01-01

    We report on a flow sensing approach based on deflection monitoring of micro beams buckled by the compressive thermal stress due to electrothermal Joules heating. The air stream convectively cooling the device affects both the critical buckling values of the electric current and the postbuckling deflections of the structure. After calibration, the flow velocity was obtained from the deflections measurements. The quasi-static responses of 2000 microns long, 10 microns wide and 30 microns high single crystal silicon beam transduced using image processing were consistent with the prediction of the reduced order model, which couples thermoelectric, thermofluidic and structural domains. The deflection sensitivity of 1.5 microns/(m/s) and the critical current sensitivity of 0.4 mA/(m/s) were registered in the experiments. Our model and experimental results collectively demonstrate feasibility of the sensing approach and further suggest that simple, robust and potentially downscalable beam-type devices may have use ...

  10. Sensor system for multi-point monitoring using bending loss of single mode optical fiber

    International Nuclear Information System (INIS)

    Applications of smart sensors have been extended to safety systems in the aerospace, transportation and civil engineering fields. In particular, structural health monitoring techniques using smart sensors have gradually become necessary and have been developed to prevent dangers to human life and damage to assets. Generally, smart sensors are based on electro-magnets and have several weaknesses, including electro-magnetic interference and distortion. Therefore, fiber optic sensors are an outstanding alternative to overcome the weaknesses of electro-magnetic sensors. However, they require expensive devices and complex systems. This paper proposes a new, affordable and simple sensor system that uses a single fiber to monitor pressures at multiple-points. Moreover, a prototype of the sensor system was manufactured and tested for a feasibility study. Based on the results of this experimental test, a relationship was carefully observed between the bend loss conditions and light-intensity. As a result, it was shown that impacts at multiple-points could be monitored.

  11. Energy Loss of High Intensity Focused Proton Beams Penetrating Metal Foils

    Science.gov (United States)

    McGuffey, C.; Qiao, B.; Kim, J.; Beg, F. N.; Wei, M. S.; Evans, M.; Fitzsimmons, P.; Stephens, R. B.; Chen, S. N.; Fuchs, J.; Nilson, P. M.; Canning, D.; Mastrosimone, D.; Foord, M. E.

    2014-10-01

    Shortpulse-laser-driven intense ion beams are appealing for applications in probing and creating high energy density plasmas. Such a beam isochorically heats and rapidly ionizes any target it enters into warm dense matter with uncertain transport and stopping properties. Here we present experimental measurements taken with the 1.25 kJ, 10 ps OMEGA EP BL shortpulse laser of the proton and carbon spectra after passing through metal foils. The laser irradiated spherically curved C targets with intensity 4×1018 W/cm2, producing proton beams with 3 MeV slope temperature and a sharp low energy cutoff at 5 MeV which has not been observed on lower energy, shorter pulse intense lasers. The beam either diverged freely or was focused to estimated 1016 p +/cm2 ps by a surrounding structure before entering the metal foils (Al or Ag and a Cu tracer layer). The proton and ion spectra were altered by the foil depending on material and whether or not the beam was focused. Transverse proton radiography probed the target with ps temporal and 10 micron spatial resolution, indicating an electrostatic field on the foil may also have affected the beam. We present complementary particle-in-cell simulations of the beam generation and transport to the foils. This work was supported by the DOE/NNSA National Laser User Facility program, Contract DE-SC0001265.

  12. A single-passage beam-position monitor system for the TRISTAN AR-to-MR transport lines

    International Nuclear Information System (INIS)

    A beam-position monitor (BPM) system has been installed in the transport lines between the Accumulation Ring (AR) and the Main Ring (MR) of TRISTAN. This system comprises stripline and button electrodes, detectors and charge-sensitive ADCs. The detector is a homodyne type synchronous-receiver at 70 MHz with four channels corresponding to four electrodes. Operation software automatically displays the detected beam position and its charge on a TV screen after each passage of the beam. The system is stable and is used to monitor the drift of the beam position. (author)

  13. Two-photon physics and online beam monitoring using the DELPHI detector at LEP

    International Nuclear Information System (INIS)

    This thesis is based on work done during 1989-1993 using the DELPHI detector at LEP, which is summarized in five articles. It consists of three main parts. The first part describes the Very Small Angle Tagger (VSAT), which is a sub-detector of the DELPHI detector at LEP. It consists of four silicon-tungsten electromagnetic calorimeter modules having a silicon strip planes for position determination. The modules are placed adjacent to the beam pipe, at ±7.7 m from the interaction point and after superconducting quadrupole magnets, allowing the detection of electrons in a polar angle range of 4 to 13 mrad. The second part is devoted to two-photon physics at DELPHI, with strong emphasis on a VSAT single-tagged event analysis. Here is shown, for the first time, evidence of hard scattering processes in single-tagged two-photon collisions. A QCD Resolved Photon Contribution (QCD-RPC) model is introduced. Data is then seen to be well described by a full VDM+(QCD-RPC) model. Different parton density functions are compared with data. The third part first describes the system for online monitoring of LEP beam background and luminosity at the DELPHI interaction point. Details are given of contributing sub-detector signals and program structure. Then follows a description of the VSAT online monitoring program (VSAT-MONITOR). A good agreement is found between the VSAT-MONITOR estimates of luminosity and beam spot and those of other detectors. Finally, results are presented of VSAT measurements of a LEP beam separation scan. 75 refs, figs

  14. Ionization Chambers for Monitoring in High-Intensity Charged Particle Beams

    OpenAIRE

    McDonald, J.; Naples, D.; Velissaris, C.; Erwin, A.; Ping, H.; Viren, B.; Diwan, M.

    2002-01-01

    Radiation-hard ionization chambers were tested using an intense electron beam from the accelerator test facility (ATF) at the Brookhaven National Laboratory (BNL). The detectors were designed to be used as the basic element for monitoring muons in the Main Injector Neutrino beamline (NuMI) at the Fermi National Accelerator Laboratory (FNAL). Measurements of linearity of response, voltage dependence, and the onset of ionization saturation as a function of gap voltage were performed.

  15. Beam position monitoring system based on EPICS and MATLAB image processing technique

    International Nuclear Information System (INIS)

    An optical X-ray beam position monitoring system has been established on Shanghai Synchrotron Radiation Facility (SSRF). The software for control, data acquisition and data processing is based on EPICS. It can capture and process a real time image to give the center position and spatial distribution of synchrotron radiations. The system has been used on SSRF beamlines and the experimental results show that the design specifications have been achieved. (authors)

  16. Beam test results of a drift velocity monitoring system for silicon drift detectors

    CERN Document Server

    Nouais, D; Bonvicini, V; Cerello, P; Giubellino, P; Hernández-Montoya, R; Kolojvari, A; Mazza, G; Nissinen, J; Rashevsky, A; Rivetti, A; Tosello, F; Vacchi, A

    2002-01-01

    We report results on drift velocity monitoring using MOS charge injectors in silicon drift detectors obtained in beam test conditions. The correction of velocity variations as small as 0.03% caused by temperature variations of the order of 0.04 K allowed to get an average space resolution along all the drift path of 28 mu m. Preliminary result demonstrating the possibility to correct for temperature gradients along the anode axis are also presented.

  17. Detection of bond failure in the anchorage zone of reinforced concrete beams via acoustic emission monitoring

    Science.gov (United States)

    Abouhussien, Ahmed A.; Hassan, Assem A. A.

    2016-07-01

    In this study, acoustic emission (AE) monitoring was utilised to identify the onset of bond failure in reinforced concrete beams. Beam anchorage specimens were designed and tested to fail in bond in the anchorage zone. The specimens included four 250 × 250 × 1500 mm beams with four variable bonded lengths (100, 200, 300, and 400 mm). Meanwhile, an additional 250 × 250 × 2440 mm beam, with 200 mm bonded length, was tested to investigate the influence of sensor location on the identification of bond damage. All beams were tested under four-point loading setup and continuously monitored using three distributed AE sensors. These attached sensors were exploited to record AE signals resulting from both cracking and bond deterioration until failure. The variations in the number of AE hits and cumulative signal strength (CSS) versus test time were evaluated to achieve early detection of crack growth and bar slippage. In addition, AE intensity analysis was performed on signal strength of collected AE signals to develop two additional parameters: historic index (H (t)) and severity (S r). The analysis of these AE parameters enabled an early detection of both first cracks (at almost the mid-span of the beam) and bar slip in either of the anchorage zones at the beams’ end before their visual observation, regardless of sensor location. The results also demonstrated a clear correlation between the damage level in terms of crack development/measured free end bar slip and AE parameters (number of hits, CSS, H(t), and S r).

  18. Group velocity delay spectroscopy technique for industrial monitoring of electron beam induced vapors

    Energy Technology Data Exchange (ETDEWEB)

    Benterou, J J; Berzins, L V; Sharma, M N

    1998-09-24

    Spectroscopic techniques are ideal for characterization and process control of electron beam generated vapor plumes. Absorption based techniques work well for a wide variety of applications, but are difficult to apply to optically dense or opaque vapor plumes. We describe an approach for monitoring optically dense vapor plumes that is based on measuring the group velocity delay of a laser beam near an optical transition to determine the vapor density. This technique has a larger dynamic range than absorption spectroscopy. We describe our progress towards a robust system to monitor aluminum vaporization in an industrial environment. Aluminum was chosen because of its prevalence in high performance aircraft alloys. In these applications, composition control of the alloy constituents is critical to the deposition process. Data is presented demonstrating the superior dynamic range of the measurement. In addition, preliminary data demonstrating aluminum vapor rate control in an electron beam evaporator is presented. Alternative applications where this technique could be useful are discussed. Keywords: Group velocity delay spectroscopy, optical beat signal, optical heterodyne, index of refraction, laser absorption spectroscopy, external cavity diode laser (ECDL), electron beam vaporization, vapor density, vapor phase manufacturing, process control

  19. Sensitivity improvement of beam current monitor with a high-Tc current sensor and SQUID

    International Nuclear Information System (INIS)

    It is widely recognized that non-destructive measurement at high resolution of the DC current of high-energy heavy-ion beams is important. Therefore, a high critical temperature (HTc) superconducting quantum interference device (SQUID) beam current monitor has been developed for use in the radioactive isotope beam factory (RIBF) at RIKEN in Japan. Unlike at other existing facilities, a low-vibration, pulse-tube refrigerator cools the HTc fabrications including the SQUID in such a way that the size of the system is reduced and the running costs are lowered. As a result, using a prototype of the HTc SQUID monitor, the intensity of a 4 μA Xe beam (10.8 MeV/u) was successfully measured with 100 nA resolution. Furthermore, since higher resolution is necessary, development of an improved HTc current sensor with two coils has begun. A spaying machine was developed to fabricate the new HTc current sensor by dip-coating a thin layer of Bi2-Sr2-Ca2-Cu3-Ox (Bi-2223) onto a 99.7% MgO ceramic substrate. Results from a new HTc current sensor produced using this machine are reported here. (author)

  20. A detector based on silica fibers for ion beam monitoring in a wide current range

    Science.gov (United States)

    Auger, M.; Braccini, S.; Carzaniga, T. S.; Ereditato, A.; Nesteruk, K. P.; Scampoli, P.

    2016-03-01

    A detector based on doped silica and optical fibers was developed to monitor the profile of particle accelerator beams of intensity ranging from 1 pA to tens of μA. Scintillation light produced in a fiber moving across the beam is measured, giving information on its position, shape and intensity. The detector was tested with a continuous proton beam at the 18 MeV Bern medical cyclotron used for radioisotope production and multi-disciplinary research. For currents from 1 pA to 20 μA, Ce3+ and Sb3+ doped silica fibers were used as sensors. Read-out systems based on photodiodes, photomultipliers and solid state photomultipliers were employed. Profiles down to the pA range were measured with this method for the first time. For currents ranging from 1 pA to 3 μA, the integral of the profile was found to be linear with respect to the beam current, which can be measured by this detector with an accuracy of ~1%. The profile was determined with a spatial resolution of 0.25 mm. For currents ranging from 5 μA to 20 μA, thermal effects affect light yield and transmission, causing distortions of the profile and limitations in monitoring capabilities. For currents higher than ~1 μA, non-doped optical fibers for both producing and transporting scintillation light were also successfully employed.

  1. SU-D-213-01: Transparent Photon Detector For The Online Monitoring Of IMRT Beams

    International Nuclear Information System (INIS)

    Purpose: An innovative Transparent Detector for Radiotherapy (TraDeRa) has been developed. The detector aims at real-time monitoring of modulated beam ahead of the patient during delivery sessions, with a field cover up to 40×40 cm 2. Methods: TraDeRa consists in a pixelated matrix of ionization chambers with a patented electrodes design. An in-house designed specific integrated circuit allows to extract the signal and provides a real-time map of beam intensity and shape, at the linac pulse-scale. The measurements under irradiation are made with a 6 MV clinical X-Ray beam. Dose calculations are performed with the Monte Carlo code PENELOPE, modeling the full accelerator head and the TraDeRa detector. Results: A 2 % attenuation of the beam was measured in the presence of TraDeRa and the PENELOPE dosimetric study showed no significant modification of the photon beam properties. TraDeRa detects error leaf position as small as 1 mm compared to a reference field, for both static and modulated fields. In addition, measurements are accurate over a large dynamic range from low intensity signals, as inter-leaves leaks, to very high intensities as obtained on the medical line of the European Synchrotron Radiation Facility. The detector is fully operational for conventional and high dose rate beams as FFF modes (up to 2400 MU/min). Conclusion: The current version of TraDeRa shows promising results for IMRT quality assurance (QA), allowing pulse-scale monitoring of the beam and high sensitivity for errors detection. The attenuation is small enough not to hinder the irradiation while keeping the beam upstream of the patient under constant control. A final prototype under development will include 1600 independent electrodes, half of them with a high resolution centered on the beam axis. This compact detector provides an independent set of measurements for a better QA. Funding support : This work was supported by the LABEX PRIMES (ANR-11-LABX-0063) of Universite de Lyon, within

  2. Measurements of the performance of a beam condition monitor prototype in a 5 GeV electron beam

    Science.gov (United States)

    Hempel, M.; Afanaciev, K.; Burtowy, P.; Dabrowski, A.; Henschel, H.; Idzik, M.; Karacheban, O.; Lange, W.; Leonard, J.; Levy, I.; Lohmann, W.; Pollak, B.; Przyborowski, D.; Ryjov, V.; Schuwalow, S.; Stickland, D.; Walsh, R.; Zagozdzinska, A.

    2016-08-01

    The Fast Beam Conditions Monitor, BCM1F, in the Compact Muon Solenoid, CMS, experiment was operated since 2008 and delivered invaluable information on the machine induced background in the inner part of the CMS detector supporting a safe operation of the inner tracker and high quality data. Due to the shortening of the time between two bunch crossings from 50 ns to 25 ns and higher expected luminosity at the Large Hadron Collider, LHC, in 2015, BCM1F needed an upgrade to higher bandwidth. In addition, BCM1F is used as an on-line luminometer operated independently of CMS. To match these requirements, the number of single crystal diamond sensors was enhanced from 8 to 24. Each sensor is subdivided into two pads, leading to 48 readout channels. Dedicated fast front-end ASICs were developed in 130 nm technology, and the back-end electronics is completely upgraded. An assembled prototype BCM1F detector comprising sensors, a fast front-end ASIC and optical analog readout was studied in a 5 GeV electron beam at the DESY-II accelerator. Results on the performance are given.

  3. Development of digital down conversion based digital beam position monitor for Indus-1

    International Nuclear Information System (INIS)

    Indus-1 is a 450 MeV synchrotron radiation source (SRS) at RRCAT Indore. For beam position measurement, four button type beam position indicators (BPls) are installed in Indus-I. A digital down conversion (DDC) algorithm based digital beam position monitor (DBPM) has been developed. Xilinx make board having Virtex-t FPGA has been used for implementation of DBPM system. The RF frequency of Indus-1 is 31.613 MHz. This DBPM processes 31.613 MHz pickup signals of beam position indicator by sampling it with 14 bit ADC at 28 MHz clock. The DDC also works at same clock of 28 MHz and generates position output. The output data rate of 10 kSPS and bandwidth of ∼ 2 kHz has been achieved by this system. System has been tested successfully in lab on calibration bench with simulated beam signals. System has also been tested in field. The design details and implementation aspects are discussed in this paper. (author)

  4. Optical transition radiation from a thin carbon foil: a beam profile monitor for the SLC

    International Nuclear Information System (INIS)

    This memo considers placement of an ultra thin carbon foil into the SLC beam. Transition radiation light would be emitted from the surface of the foil. The optical spot from the foil could be viewed with a microscope objective lens and registered with an image detector. Multiple scattering for the foil thicknesses necessary will not affect the beam emittance. Calculations show that a thin carbon foil can withstand the electron beam if the electron beam is larger than 10 μm in size. There are many possible radiation mechanisms from a foil - bremsstrahlung, black body temperature radiation, Cerenkov light, scintillation light, and transition radiation. Transition radiation is apparently dominant. It is proposed to use thin carbon foils, 75 to 150 A thick. Calculations indicate that 5 x 1010 beam electrons will radiate a useable number of optical photons. Specifically with 150 A foils the fractional yield of useful optical photons is 10-3 photons per incident electron 5 x 10+7 optical photons imaged upon an image plane. Spread these photons over a 32 x 32 pixel CCD and one has the readout system of a monitor

  5. New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end.

    Science.gov (United States)

    Takahashi, Sunao; Kudo, Togo; Sano, Mutsumi; Watanabe, Atsuo; Tajiri, Hiroo

    2016-08-01

    A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in "de-flattening" of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm(2) beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid could be detected with a resolution of less than 0.1 mm. PMID:27587104

  6. Touch-sensitive colour graphics enhance monitoring of loss-of-coolant accident tests

    International Nuclear Information System (INIS)

    A stand-alone computer-based system with an intelligent colour termimal is described for monitoring parameters during loss-of-coolant accident tests. Colour graphic displays and touch-sensitive control have been combined for effective operator interaction. Data collected by the host MODCOMP II minicomputer are dynamically updated on colour pictures generated by the terminal. Experimenters select system functions by touching simulated switches on a transparent touch-sensitive overlay, mounted directly over the face of the colour screen, eliminating the need for a keyboard. Switch labels and colours are changed on the screen by the terminal software as different functions are selected. Interaction is self-prompting and can be learned quickly. System operation for a complete set of 20 tests has demonstrated the convenience of interactive touchsensitive colour graphics

  7. A procedure for calculation of monitor units for passively scattered proton radiotherapy beams.

    Science.gov (United States)

    Sahoo, Narayan; Zhu, X Ronald; Arjomandy, Bijan; Ciangaru, George; Lii, MingFwu; Amos, Richard; Wu, Richard; Gillin, Michael T

    2008-11-01

    The purpose of this study is to validate a monitor unit (MU) calculation procedure for passively scattered proton therapy beams. The output dose per MU (d/MU) of a therapeutic radiation beam is traditionally calibrated under specific reference conditions. These conditions include beam energy, field size, suitable depth in water or water equivalent phantom in a low dose gradient region with known relative depth dose, and source to point of calibration distance. Treatment field settings usually differ from these reference conditions leading to a different d/MU that needs to be determined for delivering the prescribed dose. For passively scattered proton beams, the proton specific parameters, which need to be defined, are related to the energy, lateral scatterers, range modulating wheel, spread out Bragg peak (SOBP) width, thickness of any range shifter, the depth dose value relative to the normalization point in the SOBP, and scatter both from the range compensator and inhomogeneity in the patient. Following the custom for photons or electrons, a set of proton dosimetry factors, representing the changes in the d/MU relative to a reference condition, can be defined as the relative output factor (ROF), SOBP factor (SOBPF), range shifter factor (RSF), SOBP off-center factor (SOBPOCF), off-center ratio (OCR), inverse square factor (ISF), field size factor (FSF), and compensator and patient scatter factor (CPSF). The ROF, SOBPF, and RSF are the major contributors to the d/MU and were measured using an ion chamber in water tank during the clinical commissioning of each beam to create a dosimetry beam data table to be used for calculating the monitor units. The following simple formula is found to provide an independent method to determine the d/MU at the point of interest (POI) in the patient, namely, (d/MU) = ROF SOBPF. RSF SOBPOCF.OCR.FSF.ISF.CPSF. The monitor units for delivering the intended dose (D) to the POI can be obtained from MU = D / (d/MU). The accuracy and

  8. A procedure for calculation of monitor units for passively scattered proton radiotherapy beams

    International Nuclear Information System (INIS)

    The purpose of this study is to validate a monitor unit (MU) calculation procedure for passively scattered proton therapy beams. The output dose per MU (d/MU) of a therapeutic radiation beam is traditionally calibrated under specific reference conditions. These conditions include beam energy, field size, suitable depth in water or water equivalent phantom in a low dose gradient region with known relative depth dose, and source to point of calibration distance. Treatment field settings usually differ from these reference conditions leading to a different d/MU that needs to be determined for delivering the prescribed dose. For passively scattered proton beams, the proton specific parameters, which need to be defined, are related to the energy, lateral scatterers, range modulating wheel, spread out Bragg peak (SOBP) width, thickness of any range shifter, the depth dose value relative to the normalization point in the SOBP, and scatter both from the range compensator and inhomogeneity in the patient. Following the custom for photons or electrons, a set of proton dosimetry factors, representing the changes in the d/MU relative to a reference condition, can be defined as the relative output factor (ROF), SOBP factor (SOBPF), range shifter factor (RSF), SOBP off-center factor (SOBPOCF), off-center ratio (OCR), inverse square factor (ISF), field size factor (FSF), and compensator and patient scatter factor (CPSF). The ROF, SOBPF, and RSF are the major contributors to the d/MU and were measured using an ion chamber in water tank during the clinical commissioning of each beam to create a dosimetry beam data table to be used for calculating the monitor units. The following simple formula is found to provide an independent method to determine the d/MU at the point of interest (POI) in the patient, namely, (d/MU)=ROF·SOBPF·RSF·SOBPOCF·OCR·FSF·ISF·CPSF. The monitor units for delivering the intended dose (D) to the POI can be obtained from MU=D divide (d/MU). The accuracy

  9. Structural health monitoring MEMS sensors using elasticity-based beam vibrations

    Science.gov (United States)

    Plankis, Alivia

    The worsening problem of aging and deficient infrastructure in this nation and across the world has demonstrated the need for an improved system to monitor and maintain these structures. The field of structural health monitoring has grown in recent years to address this issue. The goal of this field is to continually monitor the condition of a structure to detect and mitigate damage that may occur. Many structural health monitoring methods have been developed and most of these require sensor systems to collect the necessary information to assess the current strength and integrity of a structure. The motivation for this thesis is a proposed new microelectromechanical systems (MEMS) sensor with applications in civil infrastructure sensing. The work required was to determine accurate estimates of the resonant frequencies for a fixed-fixed silicon bridge within the device so that further testing and development could proceed. Additional knowledge and information were essential, though, before these requested calculations could be performed confidently. First, a thorough review of current structural health monitoring concepts and methods was performed to better understand the field in which this device would be applied and what incentive existed to develop a new sensor. Second, an in-depth investigation of vibrational beam mechanics theories was completed to ensure the accuracy of the frequency results for the new MEMS sensor. This study analyzed the influence of three assumptions employed in the Euler-Bernoulli, Rayleigh, and Timoshenko beam theories by comparing their results to a three-dimensional, elasticity-based approximation for vibrational frequencies and mode shapes. The results of this study showed that all three theories are insufficient when a fixed support is involved, so the elasticity-based approximation was utilized to calculate the frequencies for the bridge component in the MEMS device. These results have been passed on to the developers so that the

  10. Modelling the Loss of Steel-Concrete Bonds in Corroded Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete....

  11. Thin conductive diamond films as beam intensity monitors for soft x-ray beamlines

    Science.gov (United States)

    Kummer, K.; Fondacaro, A.; Yakhou-Harris, F.; Sessi, V.; Pobedinskas, P.; Janssens, S. D.; Haenen, K.; Williams, O. A.; Hees, J.; Brookes, N. B.

    2013-03-01

    Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for monitoring the beam intensity of soft X-ray beamlines in situ. Limited by the carbon extended x-ray absorption fine structure oscillations, the diamond films become applicable beginning from about 600 eV photon energy, where the important transition metal edges and the rare-earth edges are found. The 100 nm and 250 nm thick free-standing diamond films were grown and tested against standard gold meshes in real-life dichroism experiments performed at beamline ID08 of the European Synchrotron Radiation Facility, Grenoble, France. Quantitative agreement was found between the two experimental data sets. The films feature an extremely high transmission of about 90% and, at the same time, yield a sufficiently strong and clean reference signal. Furthermore, the thin films do not affect the shape of the transmitted beam. X-rays passing mesh-type monitors are subject to diffraction effects, which widen the beam and become particularly disturbing for small beamsizes in the micrometer range.

  12. On-line neutron monitoring system of epithermal neutron beam for BNCT at THOR

    International Nuclear Information System (INIS)

    This paper aims to introduce the on-line neutron monitoring system (NMS) of epithermal neutron beam for BNCT at THOR and following tests. The NMS consists of three miniature fission chambers (Centronic, FC4A) and one gamma-ray monitor. The data acquisition and display are controlled by an in-house graphical user interface program. Both the real-time counting rates and the accumulated counts will be displayed simultaneously during irradiation. When the accumulated count reaches a preset value, the NMS will send a signal to the reactor operator to shut down the reactor. Examinations have been performed to demonstrate the system's reliability and linearity for desired reactor power range. The neutron counting rates were calibrated to the reaction rate of the gold foil measured free-in-air at the beam outlet center. By using the on-line NMS, an unstable fluctuation and long-term depression of epithermal neutron beam intensity was observed. It is suggested to normalize each performed irradiation by the average reading of the NMS. (author)

  13. Bunch-shape monitor for a picosecond single-bunch beam of a 35 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    A non-interactive-type bunch-shape and beam intensity monitor for a 35 MeV electron linear accelerator (linac) has been developed. The monitor consists of an electric SMA-type connector and an Al pipe of 50 mm inner diameter. Test measurements of the present monitor have been made under the conditions of the accelerated charges of lower than 27 nC/pulse and the pulse width ranging from 6 to 30 ps (Full Width at Half Maximum). The results show that the present monitor is applicable to bunch-shape measurement of the picosecond single-bunch beam. The monitor output is also found to be proportional to the beam intensity of more than 0.05 nC/pulse. (author)

  14. Bunch-Shape Monitor for a Picosecond Single-Bunch Beam of a 35 MeV Electron Linear Accelerator

    Science.gov (United States)

    Hosono, Yoneichi; Nakazawa, Masaharu; Iguchi, Tetsuo; Ueda, Touru; Kobayashi, Tosiaki; Kozawa, Takahiro; Uesaka, Mitsuru; Ohkuma, Juzo; Okuda, Shuichi; Yamamoto, Tamotsu; Suemine, Shoji

    1995-09-01

    A non-interactive-type bunch-shape and beam intensity monitor for a 35 MeV electron linear accelerator (linac) has been developed. The monitor consists of an electric SMA-type connector and an Al pipe of 50 mm inner diameter. Test measurements of the present monitor have been made under the conditions of the accelerated charges of lower than 27 nC/pulse and the pulse width ranging from 6 to 30 ps (Full Width at Half Maximum). The results show that the present monitor is applicable to bunch-shape measurement of the picosecond single-bunch beam. The monitor output is also found to be proportional to the beam intensity of more than 0.05 nC/pulse.

  15. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    International Nuclear Information System (INIS)

    We have determined ''effective'' Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  16. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    Science.gov (United States)

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-01

    We have determined "effective" Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  17. Acoustic emission monitoring of concrete columns and beams strengthened with fiber reinforced polymer sheets

    Science.gov (United States)

    Ma, Gao; Li, Hui; Zhou, Wensong; Xian, Guijun

    2012-04-01

    Acoustic emission (AE) technique is an effective method in the nondestructive testing (NDT) field of civil engineering. During the last two decades, Fiber reinforced polymer (FRP) has been widely used in repairing and strengthening concrete structures. The damage state of FRP strengthened concrete structures has become an important issue during the service period of the structure and it is a meaningful work to use AE technique as a nondestructive method to assess its damage state. The present study reports AE monitoring results of axial compression tests carried on basalt fiber reinforced polymer (BFRP) confined concrete columns and three-point-bending tests carried on BFRP reinforced concrete beams. AE parameters analysis was firstly utilized to give preliminary results of the concrete fracture process of these specimens. It was found that cumulative AE events can reflect the fracture development trend of both BFRP confined concrete columns and BFRP strengthened concrete beams and AE events had an abrupt increase at the point of BFRP breakage. Then the fracture process of BFRP confined concrete columns and BFRP strengthened concrete beams was studied through RA value-average frequency analysis. The RA value-average frequency tendencies of BFRP confined concrete were found different from that of BFRP strengthened concrete beams. The variation tendency of concrete crack patterns during the loading process was revealed.

  18. A novel Beam Halo Monitor for the CMS experiment at the LHC

    International Nuclear Information System (INIS)

    A novel Beam Halo Monitor (BHM) has been designed and built for the CMS experiment at the LHC. It will provide an online, bunch-by-bunch measurement of background particles created by interactions of the proton beam with residual gas molecules in the vacuum chamber or with collimator material upstream of CMS. The BHM consists of two arrays of twenty detectors that are mounted around the outer forward shielding of the CMS experiment. Each detector is comprised of a cylindrical quartz radiator, optically coupled to a fast ultraviolet-sensitive photomultiplier tube from one end and painted black at the opposite end. Particles moving towards the photomultiplier tube will be detected with time resolution of a few nanoseconds, allowing to measure the flux of background particles produced upstream of CMS and suppress signals from collision-induced products. Monte Carlo simulations were performed to optimise the detector design. Prior to installation, the performance of the prototype detectors was measured in test beams quantifying the detector's direction-sensitive response and time resolution. The BHM was installed during the first LHC long shutdown (LS1) and is currently being commissioned. Design considerations, results from the test-beams supporting the design and the installation of the BHM in the CMS are presented

  19. A novel Beam Halo Monitor for the CMS experiment at the LHC

    Science.gov (United States)

    Orfanelli, S.; Dabrowski, A. E.; Giunta, M.; Loos, R.; Ambrose, M. J.; Mans, J.; Rusack, R.; Stifter, K.; Stickland, D.; Fabbri, F.; Manna, A.; Montanari, A.; Tosi, N.; Calvelli, V.

    2015-11-01

    A novel Beam Halo Monitor (BHM) has been designed and built for the CMS experiment at the LHC. It will provide an online, bunch-by-bunch measurement of background particles created by interactions of the proton beam with residual gas molecules in the vacuum chamber or with collimator material upstream of CMS. The BHM consists of two arrays of twenty detectors that are mounted around the outer forward shielding of the CMS experiment. Each detector is comprised of a cylindrical quartz radiator, optically coupled to a fast ultraviolet-sensitive photomultiplier tube from one end and painted black at the opposite end. Particles moving towards the photomultiplier tube will be detected with time resolution of a few nanoseconds, allowing to measure the flux of background particles produced upstream of CMS and suppress signals from collision-induced products. Monte Carlo simulations were performed to optimise the detector design. Prior to installation, the performance of the prototype detectors was measured in test beams quantifying the detector's direction-sensitive response and time resolution. The BHM was installed during the first LHC long shutdown (LS1) and is currently being commissioned. Design considerations, results from the test-beams supporting the design and the installation of the BHM in the CMS are presented.

  20. Test results on the silicon pixel detector for the TTF-FEL beam trajectory monitor

    Science.gov (United States)

    Hillert, S.; Ischebeck, R.; Müller, U. C.; Roth, S.; Hansen, K.; Holl, P.; Karstensen, S.; Kemmer, J.; Klanner, R.; Lechner, P.; Leenen, M.; Ng, J. S. T.; Schmüser, P.; Strüder, L.

    2001-02-01

    Test measurements on the silicon pixel detector for the beam trajectory monitor at the free-electron laser of the TESLA test facility are presented. To determine the electronic noise of the detector and the read-out electronics and to calibrate the signal amplitude of different pixels, the 6 keV photons of the manganese K α/K β line are used. Two different methods determine the spatial accuracy of the detector: in one setup a laser beam is focused to a straight line and moves across the pixel structure. In the other, the detector is scanned using a low-intensity electron beam of an electron microscope. Both methods show that the symmetry axis of the detector defines a straight line within 0.4 μm. The sensitivity of the detector to low-energy X-rays is measured using a vacuum ultraviolet beam at the synchrotron light source HASYLAB. Additionally, the electron microscope is used to study the radiation hardness of the detector.