Dr. Roland Beyer

Beam line scientist, radiation protection officer FWK
Nuclear Physics
Phone: +49 351 260 3281

Automatic Setup of QACs of the V874B TAPS Modules

The pedestal of the V874B TAPS Modules should uniformly be set to channel 100. To do this, a automatic routine, "SetPed", is implemented to the f_user.c of the  inelastic scattering setup. SetPed changes the v874b_#_pedXY values, set in the setup_vme_0.ini and setup_vme_1.ini file, in that way that the pedestal value of 100 is reached iteratively for each single channel. A comment is written to the mbsprint_vme_1.l and mbsprint_vme_1.l log-file every time one value was fixed and when all modules are ready.

To run SetPed one has to do the following steps:

  1. turn off all detectors
  2. set "setped" value in setup_vme_0.ini file to "1" (enable)
  3. set "setped" value in setup_vme_1.ini file to "1" (enable)
  4. close setup_vme_0.ini file if opened with any text editor
  5. close setup_vme_1.ini file if opened with any text editor
  6. rio3::start acquisition
  7. look at mbsprint_vme_0.l and mbsprint_vme_1.l log (via "tail -f") until the comment appears: "<I>: SetPed: all modules ready" (see also Note 2.)
  8. rio3::stop acquisition
  9. set "setped" value in setup_vme_0.ini file to "0" (disable)
  10. set "setped" value in setup_vme_1.ini file to "0" (disable)
  11. turn on the detectors


1. Setting the "setped" value to "1" has the following consequences:
- the LNE prescale factor (cf. manual p. 27) of scaler 3 will be set to 9999 that means a LNE fequency of 1 kHz, which will be present on control output 5
- all input channels of scaler 3 will be inhibited
- the over-range- and low-threshold-suppression of the TAPS Modules will be disabled
- all BaF ADC Data words will be written to stream even if measured value below v874b_bafsendthr
- some SetPed comments will be written to mbsprint_vme_*.l log files
- a new setup_vme_*.ini files will be written after "stop acquisition"
- the following setting for the V1495 will be set:
v1495_trig_scal = 1
v1495_a_mask_l = 0x8000
v1495_a_mask_h = 0x0000
v1495_d_mask_l = 0x0000
v1495_d_mask_h = 0x0000
v1495_e_mask_l = 0x0000
v1495_e_mask_h = 0x0000
v1495_f_mask_l = 0xFFFF
v1495_f_mask_h = 0xFFFF
2. One should monitor the SetPed Procedure with LEA (or Go4) by checking all LG, SG, LGS and SGS spectra. If one pedestal is missing or below 10 one has to set the corresponding v874b_#_pedXY value in the setup_vme_*.ini files by hand to an initial value of 5376 and rerun SetPed via "rio3::sta acq". (You can also choose any other initial value if you consider the following: The lower the v874b_#_pedXY value the higher will be the pedestal, and vice versa.)