skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Energy Calibration of the JLab Bremsstrahlung Tagging System

Abstract

In this report, we present the energy calibration of the Hall B bremsstrahlung tagging system at the Thomas Jefferson National Accelerator Facility. The calibration was performed using a magnetic pair spectrometer. The tagged photon energy spectrum was measured in coincidence with e{sup +}e{sup -} pairs as a function of the pair spectrometer magnetic field. Taking advantage of the internal linearity of the pair spectrometer, the energy of the tagging system was calibrated at the level of {+-} 0.1% E{sub {gamma}}. The absolute energy scale was determined using the e{sup +}e{sup -} rate measurements close to the end-point of the photon spectrum. The energy variations across the full tagging range were found to be <3 MeV.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
890520
Report Number(s):
JLAB-PHY-06-535; DOE/ER/40150-4009
TRN: US0604598
DOE Contract Number:
AC05-84ER40150
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nucl.Instrum.Meth.A; Journal Volume: 572; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BREMSSTRAHLUNG; CALIBRATION; CEBAF ACCELERATOR; MAGNETIC FIELDS; PAIR SPECTROMETERS; PHOTONS

Citation Formats

Stepan Stepanyan, S. Boyarinov, H. Egiyan, D. Dale, L. Guo, M. Gabrielyan, L. Gan, Ashot Gasparian, Bernhard Mecking, A. Teymurazyan, I. Nakagawa, Oleksandr Glamazdin, and Michael Wood. Energy Calibration of the JLab Bremsstrahlung Tagging System. United States: N. p., 2007. Web. doi:10.1016/j.nima.2006.12.009.
Stepan Stepanyan, S. Boyarinov, H. Egiyan, D. Dale, L. Guo, M. Gabrielyan, L. Gan, Ashot Gasparian, Bernhard Mecking, A. Teymurazyan, I. Nakagawa, Oleksandr Glamazdin, & Michael Wood. Energy Calibration of the JLab Bremsstrahlung Tagging System. United States. doi:10.1016/j.nima.2006.12.009.
Stepan Stepanyan, S. Boyarinov, H. Egiyan, D. Dale, L. Guo, M. Gabrielyan, L. Gan, Ashot Gasparian, Bernhard Mecking, A. Teymurazyan, I. Nakagawa, Oleksandr Glamazdin, and Michael Wood. Thu . "Energy Calibration of the JLab Bremsstrahlung Tagging System". United States. doi:10.1016/j.nima.2006.12.009. https://www.osti.gov/servlets/purl/890520.
@article{osti_890520,
title = {Energy Calibration of the JLab Bremsstrahlung Tagging System},
author = {Stepan Stepanyan and S. Boyarinov and H. Egiyan and D. Dale and L. Guo and M. Gabrielyan and L. Gan and Ashot Gasparian and Bernhard Mecking and A. Teymurazyan and I. Nakagawa and Oleksandr Glamazdin and Michael Wood},
abstractNote = {In this report, we present the energy calibration of the Hall B bremsstrahlung tagging system at the Thomas Jefferson National Accelerator Facility. The calibration was performed using a magnetic pair spectrometer. The tagged photon energy spectrum was measured in coincidence with e{sup +}e{sup -} pairs as a function of the pair spectrometer magnetic field. Taking advantage of the internal linearity of the pair spectrometer, the energy of the tagging system was calibrated at the level of {+-} 0.1% E{sub {gamma}}. The absolute energy scale was determined using the e{sup +}e{sup -} rate measurements close to the end-point of the photon spectrum. The energy variations across the full tagging range were found to be <3 MeV.},
doi = {10.1016/j.nima.2006.12.009},
journal = {Nucl.Instrum.Meth.A},
number = 2,
volume = 572,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • As part of the planned Jefferson Laboratory's electron accelerator (CEBAF) power upgrade, ten additional superconducting RF cryomodules will be added to its accelerator linacs. Although physically the same size as each of the original 40 linac cryomodules, each new cryomodule will have approximately 4 times the acceleration power. To support the additional cryomodule heat loads generated, the existing 2 K, 4600 W Central Helium Liquefier (CHL) plant capacity will be doubled to a total of 9200 W at 2 K plus 24,000 W at 35 K for shield loads. The specified base line process cycle has been modeled after themore » laboratory's 'Ganni Helium Cycle' process technology. In addition, a fourth physics experimental 'Hall D' will be constructed which will have an additional stand alone 200 W at 4 K helium cryogenic plant. In October of 2008, Jefferson Laboratory (JLab) received approval for project 'Critical Decision 3' construction phase status from the US Department of Energy. An overview of the planned cryogenic systems and current design baseline as it relates to operations will be presented.« less
  • The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.
  • The Central Helium Liquefier (CHL) distribution system to the CEBAF and FEL linacs at Jefferson Lab (JLab) experienced a planned warm up during the late summer and fall of 2012 for the first time after its commissioning in 1991. Various maintenance and modifications were performed to support high beam availability to the experimental users, meet 10 CFR 851 requirements for pressure systems, address operational issues, and prepare the cryogenic interfaces for the high-gradient cryomodules needed for the 12 GeV upgrade. Cryogenic maintenance and installation work had to be coordinated with other activities in the linacs and compete for manpower frommore » other department installation activities. With less than a quarter of the gas storage capacity available to handle the boil-off from the more than 40 cryomodules, 35,000 Nm{sup 3} of helium was re-liquefied and shipped to a vendor via a liquid tanker trailer. Nearly 200 u-tubes had to be removed and stored while seals were replaced on related equipment such as vacuum pump outs, bayonet isolation and process valves.« less