Data Analysis - General Parameters

General Parameters

General parameters are broken into two categories; parameters that are not spectrometer specific, and those that are spectrometer specific. The general parameters are included in the general.param files located at DBASE/<spec> Common general parameters used for the hall C beamline and debug mode are stored in the PARAM/GEN/ directory. Spectrometer specific general parameters are included at:
PARAM/SHMS/GEN/
PARAM/HMS/GEN/

Non-Spectrometer Specific General Parameters

There used to be energy loss parameters included in this directory for the old Fortran analyzer. The C++ analyzer no longer calculates energy loss, so the variables associated with energy loss have been removed.
The main parameters of this section are the BCM scalers and the BPM positions from HARP scans and the raster conversions. These aspects have their own devoted analysis section.

Global GEN Files

• PARAM/GEN/genflags.param - Only includes the gen_run_starting_event parameter.
• PARAM/GEN/gdebug.param - No used parameters
• PARAM/GEN/gtarget.param - No used parameters, Eloss not included in hcana. Eloss handeled in rc-externals
• PARAM/GEN/gbeam.param - Calibration of beam position on target and raster settings.
• PARAM/GEN/gscalers.param - Calibration of scaler BCM branches. Must be set before running the BCM calibration procedure.

gscalers

gscalers.param gNumBCMs = 6 gBCM_Names = " BCM1 BCM2 Unser BCM4A BCM4B BCM4C" gBCM_Gain = 4795.0, 4092.0, 4000.0, 13020.0, 2042.0, 6238.0 gBCM_Offset = 250300.0, 250200.0, 393000.0, 432.4, 204.9, 127.8 gBCM_Current_threshold = 5.0

index = 0 to gNumBCMs-1

gBCM_Current_threshold_index = 3

gbeam

gbeam_sp18.param

BPM calibration constants

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average beam positions

Use the Hall C EPICS BPM values in units of cm

gbeam_x = +0.00

gbeam_xp = +0.00

gbeam_y = +0.00

gbeam_yp = +0.00

Add new variables for Hall C BPM A, B, and C, based on HARP calibration

Updated by Dave Gaskell

 gbpmxa_slope = -0.98
 gbpmxa_off   = -0.05
 gbpmxb_slope = -1.12
 gbpmxb_off   = +0.08
 gbpmxc_slope = -0.96
 gbpmxc_off   = -0.89
 gbpmya_slope = 0.97
 gbpmya_off   = -0.20
 gbpmyb_slope = 1.17
 gbpmyb_off   = 0.38
 gbpmyc_slope = 0.87
 gbpmyc_off   = 0.47

positions of BPMs relative to target (from DIMAD)

gbpma_zpos = 370.82 ; cm

gbpmb_zpos = 224.96 ; cm

gbpmc_zpos = 129.30 ; cm

positions of BPMs relative to target (from Fall 2017 survey)

gbpma_zpos = 320.42 ; cm gbpmb_zpos = 224.86 ; cm gbpmc_zpos = 129.44 ; cm

positions of BPMs relative to target (from Fall 2018 survey)

gbpma_zpos = 320.17 ; cm

gbpmb_zpos = 224.81 ; cm

gbpmc_zpos = 129.38 ; cm

Fast Raster calibration constants

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 gusefr               = 1  

flag if 1 fast raster data used with average beam pos and angles in

calculating beam position

if 0 then only use average beam pos and angles in calculating beam position

Various fast raster quantities

gUse* are flags

Raster constants determined from coin run 4556 on Aug 20, 2018

gfr_cal_mom = 8.518

gfrxa_adc_zero_offset = 64150

gfrxb_adc_zero_offset = 66250

gfrya_adc_zero_offset = 67700

gfryb_adc_zero_offset = 64100

gfrxa_adcpercm = 158000

gfrxb_adcpercm = 147000

gfrya_adcpercm = 155500

gfryb_adcpercm = 157500

 gfr_cal_mom  = 6.4  ; = beam momentum during jan 2018 3 pass 
      
 gfrya_adcpercm = (77755.-57411.)/.2;
 gfryb_adcpercm = (71093.-52056.)/.2;
 gfrxa_adcpercm = (75733.-51938.)/.2;
 gfrxb_adcpercm =  (79778.-57293.)/.2;

 gfrya_adc_zero_offset = (77755.+57411.)/2.;
 gfryb_adc_zero_offset = (71093.+52056.)/2.;
 gfrxa_adc_zero_offset = (75733.+51938.)/2.;
 gfrxb_adc_zero_offset = (79778.+57293.)/2. ;

positions of FR magnets relative to target

 gfrx_dist  = 1375   ; cm
 gfry_dist  = 1337   ; cm