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Title: Precision electron-beam polarimetry at 1 GeV using diamond microstrip detectors

We report on the highest precision yet achieved in the measurement of the polarization of a low-energy, O(1 GeV), continuous-wave (CW) electron beam, accomplished using a new polarimeter based on electron-photon scattering, in Hall C at Jefferson Lab. A number of technical innovations were necessary, including a novel method for precise control of the laser polarization in a cavity and a novel diamond microstrip detector that was able to capture most of the spectrum of scattered electrons. The data analysis technique exploited track finding, the high granularity of the detector, and its large acceptance. The polarization of the 180–μA, 1.16-GeV electron beam was measured with a statistical precision of <1% per hour and a systematic uncertainty of 0.59%. This exceeds the level of precision required by the Q weak experiment, a measurement of the weak vector charge of the proton. Proposed future low-energy experiments require polarization uncertainty < 0.4%, and this result represents an important demonstration of that possibility. This measurement is the first use of diamond detectors for particle tracking in an experiment. As a result, it demonstrates the stable operation of a diamond-based tracking detector in a high radiation environment, for two years.
 [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [1] ;  [1] ;  [5] ;  [2] ;  [6] ;  [7] ;  [8] ;  [2] ; ;  [8] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] more »;  [13] ;  [13] ;  [14] ;  [5] ;  [5] ;  [7] ;  [7] ;  [2] ;  [15] ;  [13] ;  [8] ;  [5] ;  [2] ;  [16] ;  [9] ;  [11] ;  [15] ;  [7] « less
  1. Mississippi State Univ., Mississippi State, MS (United States)
  2. Univ. of Virginia, Charlottesville, VA (United States)
  3. College of William and Mary, Williamsburg, VA (United States)
  4. Univ. of Virginia, Charlottesville, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  5. Univ. of Winnipeg, Winnipeg, MB (Canada)
  6. Univ. of Winnipeg, Winnipeg, MB (Canada); Univ. of Manitoba, Winnipeg, MB (Canada)
  7. Yerevan Physics Inst. (YerPhI), Yerevan (Armenia)
  8. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  9. MIT Bates Linear Accelerator Center, Middleton, MA (United States)
  10. Univ. of Connecticut, Storrs, CT (United States)
  11. Ohio Univ., Athens, OH (United States)
  12. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  13. TRIUMF, Vancouver, BC (Canada)
  14. Univ. of Pittsburgh, Pittsburgh, PA (United States)
  15. Univ. of Manitoba, Winnipeg, MB (Canada)
  16. Hendrix College, Conway, AR (United States)
Publication Date:
Report Number(s):
JLAB-PHY-15-2108; DOE/OR/23177-3554
Journal ID: ISSN 2160-3308; PRXHAE
Grant/Contract Number:
Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 6; Journal Issue: 1; Journal ID: ISSN 2160-3308
American Physical Society
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1238141