Instrumentation and Controls
Tech 18: Radiation Monitoring and Safety
Paper Title Page
MOP272 Radiation Dose Level in the SSRF during Normal Operation 615
 
  • X.J. Xu, P. Fei, R. Qin, W. Shen, X. Xia, D. Zhang, J.Z. Zhou
    SINAP, Shanghai, People's Republic of China
 
  Shanghai Synchrotron Radiation Facility (SSRF) has been commissioned since December 2007, and has been formally operated since May 2009. In order to ensure the radiation safety for staff members and publics, the radiation levels of the workplace, the environment and the staff are monitored through a real-time network of gamma and neutron monitors as well as through TLD passive dosimeters. This paper reports the results of the radiation monitoring. From these results, we found that the annual dose equivalents were good to meet the management values of SSRF.  
 
MOP273 Calibration and Simulation of the LCLS Undulator Beam Loss Monitors using APS Accelerators 618
 
  • J.C. Dooling, W. Berg, A.R. Brill, L. Erwin, B.X. Yang
    ANL, Argonne, USA
  • A.S. Fisher, H.-D. Nuhn, M. Santana-Leitner
    SLAC, Menlo Park, California, USA
 
  Funding: U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357
Electrons scattered by alumina ceramic transverse beam profile monitors inserted in the Advanced Photon Source (APS) booster-to-storage ring (BTS) transfer line are used to generate C ̆erenkov light for calibration of beam loss monitors (BLMs) installed in the Linac Coherent Light Source (LCLS) undulator beamline. In addition, gas bremsstrahlung (GB) photons generated by 7-GeV electrons in the APS sector 35 storage ring straight section are used to create pair-production electrons for measurement and calibration purposes. Both cases are modeled with the particle-matter interaction program MARS. The realized tuning fork geometry of the BLM exhibits regions of greater sensitivity in the radiator. Transverse GB beam scans have provided uniformity and sensitivity data throughout the volume of the radiator. Comparisons between predicted and measured signal strengths and thermoluminescent dosimeter readings are given and shown to be in reasonable agreement.
 
 
MOP274 Beam Loss Monitors for NSLS-II Storage Ring 621
 
  • S.L. Kramer, P. Cameron
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed these levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. In order to measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber wall. This will be done using the Cerenkov light as charged particles transit an ultra-pure fused silica rod placed close to the inner edge of the VC. The length of rod will collect the light from many charged particles of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.
 
 
MOP275 Beam Loss Control for the NSLS-II Storage Ring 624
 
  • S.L. Kramer, J. Choi
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region.
* Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings
 
 
MOP276 Applying Cascaded Parameter Scan to Study Top-off Safety in NSLS-II Storage Ring 627
 
  • Y. Li, S.V. Badea, W.R. Casey, G. Ganetis, R. Heese, H.-C. Hseuh, P.K. Job, S. Krinsky, B. Parker, T.V. Shaftan, S.K. Sharma, L. Yang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
In this paper we introduce a new algorithm, the cascaded parameter scan method, to efficiently carry out the scan over magnet parameters in the safety analysis for the NSLS-II top-off injection. In top-off safety analysis, one must track particles populating phase space through a beamline containing magnets and apertures and clearly demonstrate that for all possible magnet settings and errors, all particles are lost on scrapers within the properly shielded region. In the usual approach, the number of tracking runs increases exponentially with the number of magnet settings. In the cascaded parameter scan method, the number of tracking runs only increases linearly. This reduction of exponential to linear dependence on the number of setpoints, greatly reduces the required computation time and allows one to more densely populate phase space and to increase the number of setpoints scanned for each magnet. An example of applying this approach to analyze an NSLS-II beamline, the damping wiggler beamline, is also given.