| Paper | Title | Page |
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| THPRB030 | Novel FPGA-based Instrumentation for Personnel Safety Systems in Particle Accelerator Facility | 3872 |
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| Personnel safety system for particle accelerator facility involves different devices to monitor gates, shielding doors, dosimetry stations, search and emergency buttons. In order to achieve the proper reliability, fail-safe and fail-proof capabilities, these systems are developed compliant with safety standards (like the IEC-61508 on ’Functional Safety’, ANSI N43.1 ’Radiation Safety for the design and operation of Particle Accelerator’ and NCRP report 88) involving stable technologies like electro-mechnaical relays and, recently, PLC. As part of the Singularity project at Frascati National Laboratories of INFN, this work will report benchmark of a new FPGA-based system from the design to the validation phase of the prototype currently operating as personnel safety system at the Beam Test Facility (BTF) of Dafne facility. This novel instrument is capable of: devices monitoring in real-time at 1 kHz, dual modular redundancy, fail-safe and fail-proof, multi-node distributed solution on optical link, radiation damage resistance and compliant with IEC-61508, ANSI N43.1 and NCRP report 88. The aim of this FPGA-based system is to illustrate the feasibility of FPGA technology in the field of personnel safety for particle accelerator in order to take advantage of a fully digital system integrated with facility control system, evaluate the related reliability and availability and realize a standard, scalable and flexible hardware solution also for other fields with similar requirements like machine protection systems. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB030 | |
| About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| THPRB059 | Radiation Safety at SOLARIS 1.5 GeV Storage Ring | 3940 |
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| Radiation measurements at Solaris are continuously performed by using 9 radiation monitor stations (RMS) located around the storage ring and the beamlines area. 4 of RMS are connected to the Personal Safety System and in case of exceeding alarm level dump the beam or close safety shutters. Moreover thermoluminescence dosimeters (TLDs) are used to registered doses in the classified areas according to the Polish regulation. Measurements are performed since 2015 when the commissioning of the storage ring has started. Since that time several improvements to the radiation shielding was done to fulfill the ALARA principle. Moreover the electron beam optimizations during the injection, ramping and operation were performed to decrease the electrons losses and the radiation level. This presentation will report on radiation measurements results obtained before and after the chopper installation. Additionally problems with radiation level while the beam current is increasing to the designed 500mA value will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB059 | |
| About • | paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| THPRB083 | Detailed Analysis Of The Baseline Dose Levels And Localized Radiation Spikes In The Arc Sections Of The Large Hadron Collider During Run 2 | 4009 |
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| The Large Hadron Collider (LHC) has eight insertion regions (IRs) which house the large experiments or accelerator equipment. These IRs are interconnected with the arc sections consisting of a periodic magnet structure. During the operation of the LHC small amounts of the beam particles are lost, creating prompt radiation fields in the accelerator tunnels and the adjacent caverns. One of the main loss mechanisms in the LHC arc sections is the interaction of the beam particles with the residual gas molecules. The analysis of the dose levels based on the beam loss measurement data shows that the majority of the measurements have similar levels, which allow to define baseline values for each arc section. The baseline levels decreased during the years 2015, 2016 and stabilised in 2017 and 2018 at annual dose levels below 50 mGy, which can be correlated with the residual gas densities in the LHC arcs. In some location of the arcs radiation spikes exceed the base line by more than two orders of magnitude. In addition to the analysis of these dose levels, a novel approach of identifying local dose maxima and the main driving mechanisms creating these radiation spikes will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB083 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| THPRB084 | Run 2 Prompt Dose Distribution and Evolution at the Large Hadron Collider and Implications for Future Accelerator Operation | 4013 |
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| During the operation of the Large Hadron Collider (LHC) small fractions of beam particles are lost, creating prompt radiation fields in the accelerator tunnels. Exposed electronics and accelerator components show lifetime degradation and stochastic Single Event Effects (SEEs) which can lead to faults and downtime of the LHC. Close to the experiments the radiation levels scale nicely with the integrated luminosity since the luminosity debris is the major contributor for creating the radiation fields in this area of the LHC. In the collimation regions it was expected that the radiation fields scale with the integrated beam intensities since the beams are continuously cleaned from particles which exceed the accelerator’s acceptance. The analysis of radiation data shows that the dose measurements in the collimation regions normalised with the integrated beam intensities for 2016 and 2017 are comparable. Against expectations, the intensity normalised radiation datasets of 2018 in these regions differ significantly from the previous years. Especially in the betatron collimation region the radiation levels are up to a factor 3 higher. The radiation levels in the collimation regions correlate with the levelling of beta-star and the crossing angle in the high luminosity experiments ATLAS and CMS. These increased normalised doses have direct implications on the expected dose levels during future LHC operation, including the High-Luminosity LHC (HL-LHC) upgrade. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB084 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| THPRB098 | FETS Personnel & Machine Interlock Systems | 4057 |
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| The Front End Test Stand (FETS) [1] is a high energy pulsed proton driver that aims to produce a perfectly chopped 50 Hz, 60 mA, 2 ms H’ beam. FETS consists of a Penning Ion source, Low Energy Beam Transport (LEBT), 4 m long bolted construction 324 MHz four vane Radio Frequency Quadrupole (RFQ). The H’ Beam will be perfectly chopped so that bunches of particles can be trapped and accelerated with very low loss into a circular accelerator. To protect personnel from X-ray radiation along with prompt neutrons & gamma radiation, a concrete block-house has been built around the facility and a personnel interlock and search system developed. This paper discusses the mechanical and electrical systems used to ensure personnel safety via the Personnel Protection System (PPS) and machine safety by use of a Programmable Logic Controller, (PLC), used as the Machine Interlock Systems. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB098 | |
| About • | paper received ※ 09 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| THPRB102 | Monte Carlo Optimization of Fast Beam Loss Monitors for LCLS-II | 4066 |
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Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515 Commissioning of the LCLS-II hard X-ray FEL is starting at SLAC National Accelerator Laboratory. This facility will ultimately accelerate electrons to 8 GeV, with beams of 375 kW at 1 MHz. At such high-powers, errant beams will need to be detected very fast -200 μs- to limit exposure and to protect beam-line and safety components. Currently, LCLS-I uses ion chambers both as Point Beam Loss Monitors (PBLM) by collimators, dumps, septa, etc., and also as Long Beam Loss Monitors (LBML) that provide detection coverage in extended areas where the accelerator enclosure is not sufficiently thick to shield full beam losses. But due to the finite ion mobility and related screening effects, ion chambers are not fast enough, and their response would not be linear at high charge rates. LCLS-II will use synthetic mono-crystalline diamond chips as PBLMs, as those offer nanosecond time resolution due to the high mobility of holes generated in the valence band by charged particles. LBLMs will be 200 m-long optical fibers, with photomultipliers to detect Cerenkov photons produced by charged particles in the fibers. Use of these technologies requires tests and models to correlate their response to different beam losses. Response functions for these detectors have been developed for the FLUKA Monte Carlo code. After benchmarking the models, these have been applied to place PBLMs at locations where signal is relatively insensitive to beam-strike uncertainties and sufficiently above electronic noise, while keeping lifetime to radiation-damage long. Also, topologies where found were one PBLM can protect several components, resulting in cost reductions. As for LBLMs, the existing model helps scale signals for different beam loss configurations as a function of the fiber position. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB102 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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