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Title: NSLS-II beamline scattered gas bremsstrahlung radiation shielding calculation

Abstract

National Synchrotron Light Source II (NSLS-II) is a new state-of-the-art 3rd generation synchrotron. The NSLS-II facility is shielded up to 3 GeV electron beam energy at 500 mA. When the gas bremsstrahlung (GB) from the storage ring is scattered by the beamline components in the first optical enclosure (FOE), the scattered radiation will pose additional radiation hazard (bypassing primary GB collimators and stops) and challenge the FOE shielding. The scattered GB radiation hazard can be mitigated by supplementary shielding or with an exclusion zone downstream of the FOE.

Authors:
; ; ;  [1]
  1. Brookhaven National Lab, Upton, New York, 11973-5000, U.S.A (United States)
Publication Date:
OSTI Identifier:
22608355
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1741; Journal Issue: 1; Conference: SRI2015: 12. international conference on synchrotron radiation instrumentation, New York, NY (United States), 6-10 Jul 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BREMSSTRAHLUNG; BYPASSES; COLLIMATORS; ELECTRON BEAMS; GEV RANGE 01-10; NSLS; RADIATION HAZARDS; SHIELDING; STORAGE RINGS; SYNCHROTRONS; VISIBLE RADIATION

Citation Formats

Popescu, Razvan, Xia, Zhenghua, E-mail: xiazhenghuacn@hotmail.com, Job, Panakkal, and Lee, Wah-Keat. NSLS-II beamline scattered gas bremsstrahlung radiation shielding calculation. United States: N. p., 2016. Web. doi:10.1063/1.4952842.
Popescu, Razvan, Xia, Zhenghua, E-mail: xiazhenghuacn@hotmail.com, Job, Panakkal, & Lee, Wah-Keat. NSLS-II beamline scattered gas bremsstrahlung radiation shielding calculation. United States. doi:10.1063/1.4952842.
Popescu, Razvan, Xia, Zhenghua, E-mail: xiazhenghuacn@hotmail.com, Job, Panakkal, and Lee, Wah-Keat. 2016. "NSLS-II beamline scattered gas bremsstrahlung radiation shielding calculation". United States. doi:10.1063/1.4952842.
@article{osti_22608355,
title = {NSLS-II beamline scattered gas bremsstrahlung radiation shielding calculation},
author = {Popescu, Razvan and Xia, Zhenghua, E-mail: xiazhenghuacn@hotmail.com and Job, Panakkal and Lee, Wah-Keat},
abstractNote = {National Synchrotron Light Source II (NSLS-II) is a new state-of-the-art 3rd generation synchrotron. The NSLS-II facility is shielded up to 3 GeV electron beam energy at 500 mA. When the gas bremsstrahlung (GB) from the storage ring is scattered by the beamline components in the first optical enclosure (FOE), the scattered radiation will pose additional radiation hazard (bypassing primary GB collimators and stops) and challenge the FOE shielding. The scattered GB radiation hazard can be mitigated by supplementary shielding or with an exclusion zone downstream of the FOE.},
doi = {10.1063/1.4952842},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1741,
place = {United States},
year = 2016,
month = 7
}
  • We present that third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and rampedmore » operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. In conclusion, this made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and the lessons learned from this process are presented.« less
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