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Title: Shielding synchrotron light sources: Advantages of circular shield walls tunnels

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1354524
Report Number(s):
BNL-113041-2016-JA
Journal ID: ISSN 0168-9002
DOE Contract Number:
SC00112704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; Journal Volume: 827
Country of Publication:
United States
Language:
English

Citation Formats

Kramer, S. L., Ghosh, V. J., and Breitfeller, M. Shielding synchrotron light sources: Advantages of circular shield walls tunnels. United States: N. p., 2016. Web. doi:10.1016/j.nima.2016.04.094.
Kramer, S. L., Ghosh, V. J., & Breitfeller, M. Shielding synchrotron light sources: Advantages of circular shield walls tunnels. United States. doi:10.1016/j.nima.2016.04.094.
Kramer, S. L., Ghosh, V. J., and Breitfeller, M. Mon . "Shielding synchrotron light sources: Advantages of circular shield walls tunnels". United States. doi:10.1016/j.nima.2016.04.094.
@article{osti_1354524,
title = {Shielding synchrotron light sources: Advantages of circular shield walls tunnels},
author = {Kramer, S. L. and Ghosh, V. J. and Breitfeller, M.},
abstractNote = {},
doi = {10.1016/j.nima.2016.04.094},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
number = ,
volume = 827,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}
  • 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 produce significantly higher neutron component dose to the experimental floor than lower energy injection and ramped operations. High energy neutrons producedmore » in the forward direction from thin target beam losses are a major component of the dose rate outside the shield walls of the tunnel. The convention has been to provide thicker 90┬░ ratchet walls to reduce this dose to the beam line users. We present an alternate circular shield wall design, which naturally and cost effectively increases the path length for this forward radiation in the shield wall and thereby substantially decreasing the dose rate for these beam losses. Here, this shield wall design will greatly reduce the dose rate to the users working near the front end optical components but will challenge the beam line designers to effectively utilize the longer length of beam line penetration in the shield wall. Additional advantages of the circular shield wall tunnel are that it's simpler to construct, allows greater access to the insertion devices and the upstream in tunnel beam line components, as well as reducing the volume of concrete and therefore the cost of the shield wall.« less
  • It is suggested that the observed circular polarization of compact extragalactic radio sources is due to both a synchrotron emission mechanism and circular repolarization in the process of quasi-longitudinal propagation of radiation through the radio sources plasmas. The addition of circular repolarization eliminates some of the difficulties in assuming synchrotron emission as the only mechanism for the observed circular polarization reported in the Weiler and de Pater (1983) catalog. 14 references.