The AGS Ggamma Meter and Calibrating the Gauss Clock

Ahrens, Leif¹ 

[1] Brookhaven National Laboratory (BNL), Upton, NY (United States). Collider-Accelerator Dept.

关键词: BROOKHAVEN AGS;    METERS;    ENERGY;    PROTON BEAMS;    POLARIZED BEAMS;    ACCELERATION;    CALIBRATION;    COUNTING RATES;    MAGNETIC FIELDS;    CORRECTIONS;    RESONANCE;    DEPOLARIZATION;    TIME DEPENDENCE;    BEAM DYNAMICS Alternating Gradient Synchrotron;   

DOI  :  10.2172/1130444
RP-ID  :  BNL--104396-2014-IR
RP-ID  :  BNL--C-A/AP/509
PID  :  OSTI ID: 1130444
Others  :  R&D Project: KBCH139
Others  :  18031
Others  :  Other: KB0202011
Others  :  TRN: US1500102

学科分类：核物理和高能物理

美国|英语

来源: SciTech Connect

【 摘 要 】

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 history for this cycle calculates B(t).