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Title: The AGS Ggamma Meter and Calibrating the Gauss Clock

During AGS Polarized Proton acceleration periods, one output from the AGS Ggamma Meter, namely the energy (or Ggamma) calculated from the magnetic field in the AGS main magnets and the beam radius- both measured in particular instant, is used to figure out the times in the AGS magnet acceleration cycle when the beam passes through a particular set of depolarizing resonances. The resonance set occur whenever a particle’s Ggamma (energy*(G/m) becomes nearly equal to n*Qx (i.e. any integer multiplied by the horizontal betatron tune). This deliverable is why the machinery is referred to as the ''Ggamma Meter'' rather than the AGS energy meter. The Ggamma Meter takes as inputs a set of measurements of frequency (F(t)), radius (r(t)), and gauss clock counts (GCC(t)). The other energy (GgammaBr) assumes the field when the gauss clock starts counting is known. The change in field to time t is given by the measured accumulated gauss clock counts multiplied by the gauss clock calibration (gauss/GCC). In order to deal with experimental data, this calibration factor gets an added ad hoc complication, namely a correction dependent on the rate of change the counting rate. The Ggamma meter takes GCC(t) and together with the past historymore » for this cycle calculates B(t).« less
Authors:
 [1]
  1. Brookhaven National Laboratory (BNL), Upton, NY (United States). Collider-Accelerator Dept.
Publication Date:
OSTI Identifier:
1130444
Report Number(s):
BNL--104396-2014-IR; BNL--C-A/AP/509
R&D Project: KBCH139; 18031; KB0202011; TRN: US1500102
DOE Contract Number:
AC02-98CH10886
Resource Type:
Technical Report
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BROOKHAVEN AGS; METERS; ENERGY; PROTON BEAMS; POLARIZED BEAMS; ACCELERATION; CALIBRATION; COUNTING RATES; MAGNETIC FIELDS; CORRECTIONS; RESONANCE; DEPOLARIZATION; TIME DEPENDENCE; BEAM DYNAMICS Alternating Gradient Synchrotron