Index: /fact/tools/rootmacros/DrsCalibration.C =================================================================== --- /fact/tools/rootmacros/DrsCalibration.C (revision 12510) +++ /fact/tools/rootmacros/DrsCalibration.C (revision 12511) @@ -42,38 +42,101 @@ vector StartCellVector ){ - // TODO this should be a parameter... -// const int NumberOfPixel = 1440; + // In order to minimize mem free and alloc actions + // the destination vector is only resized, if it is way too big + // or too small + size_t DestinationLength = RegionOfInterest-LeaveOutRight-LeaveOutLeft; + if ( destination.size() < DestinationLength || destination.size() > 2 * DestinationLength ){ + destination.resize( DestinationLength ); + } -// if ( RegionOfInterest < drs_triggeroffsetmean.size()/NumberOfPixel ){ -// cerr << "Error in applyDrsCalibration: ROI of data is:" << RegionOfInterest << endl; -// cerr << "While ROI of 'TriggerOffset' is:" << drs_triggeroffsetmean.size()/NumberOfPixel << endl; -// cerr << "Data ROI must be <= ROI of TriggerOffset. Aborting..." << endl; -// return 0 -// } + // the vector drs_triggeroffsetmean is not 1440 * 1024 entries long + // but has hopefully the length 1440 * RegionOfInterest (or longer) + if ( drs_triggeroffsetmean.size() < 1440*RegionOfInterest ){ + return 0; + } + // We do not entirely know how the calibration constants, which are saved in a filename.drs.fits file + // were calculated, so it is not fully clear how they should be applied to the raw data for calibration. + // apparently the calibration constants were transformed to the unit mV, which means we have to do the same to + // the raw data prior to apply the calibration + // + // on the FAD board, there is a 12bit ADC, with a 2.0V range, so the factor between ADC units and mV is + // ADC2mV = 2000/4096. = 0.48828125 (numerically exact) + // + // from the schematic of the FAD we learned, that the voltage at the ADC + // should be 1907.35 mV when the calibration DAC is set to 50000. + // + // One would further assume that the calibration constants are calculated like this: - destination.clear(); + // The DRS Offset of each bin in each channel is the mean value in this very bin, + // obtained from so called DRS pedestal data + // Its value is about -1820 ADC units or -910mV + + // In order to obtain the DRS Gain of each bin of each channel + // again data is takes, with the calibration DAC set to 50000 + // This is called DRS calibration data. + // We assume the DRS Offset is already subtracted from the DRS calibration data + // so the typical value is assumed to be ~3600 ADC units oder ~1800mV + // As mentioned before, the value *should* be 1907.35 mV + // So one might assume that the Gain is a number, which actually converts ~3600 ADC units into 1907.35mV for each bin of each channel. + // So that the calibration procedure looks like this + // TrueValue = (RawValue - Offset) * Gain + // The numerical value of Gain would differ slightly from the theoretical value of 2000/4096. + // But this is apparently not the case. + // The Gain, as it is stored in the DRS calibration file of FACT++ has numerical values + // around +1800. + // So it seems one should calibrate like this: + // TrueValue = (RawValue - Offset) / Gain * 1907.35 + + // When these calibrations are done, one ends up with a quite nice calibrated voltage. + // But it turns out that, if one returns the first measurement, and calculates the mean voltages + // in each bin of the now *logical* DRS pipeline, the mean voltage is not zero, but slightly varies + // So one can store these systematical deviations from zero in the logical pipeline as well, and subtract them. + // The remaining question is, when to subtract them. + // I assume, in the process of measuring this third calibration constant, the first two + // calibrations are already applied to the raw data. + + // So the calculation of the calibrated volatage from some raw voltage works like this: + // assume the raw voltage is the s'th sample in channel c. While the Trigger made the DRS stopp in its t'th cell. + // note, that the DRS pipeline is always 1024 bins long. This is constant of the DRS4 chip. + + // TrueValue[c][s] = ( RawValue[c][s] - Offset[c][ (c+t)%1024 ] ) / Gain[c][ (c+t)%1024 ] * 1907.35 - TriggerOffset[c][s] + + + + const float dconv = 2000/4096.0; - float vraw, vcal; - unsigned int pixel_pt; - unsigned int slice_pt; - unsigned int cal_pt; - unsigned int drs_cal_offset; + float vraw; +// float vcal; +// unsigned int pixel_pt; +// unsigned int slice_pt; +// unsigned int cal_pt; +// unsigned int drs_cal_offset; - pixel_pt = pixel * RegionOfInterest; + if ( RegionOfInterest != AllPixelDataVector.size()/1440 ){ + cout << "RegionOfInterest != AllPixelDataVector.size()/1440 .. this makes no sense ... I guess ... aborting" << endl; + return 0; + } -// unsigned int pixel_pt_TriggerOffset = pixel * drs_triggeroffsetmean.size()/NumberOfPixel; -// unsigned int slice_pti_TriggerOffset; + int Offset_offset = pixel * drs_basemean.size()/1440; + int Gain_offset = pixel * drs_gainmean.size()/1440; + int TriggerOffset_offset = pixel * drs_triggeroffsetmean.size()/1440; + int Data_offset = pixel * RegionOfInterest; + + for ( unsigned int sl = LeaveOutLeft; sl < RegionOfInterest-LeaveOutRight ; sl++){ + vraw = AllPixelDataVector[ Data_offset + sl ] * dconv; + vraw -= drs_basemean[ Offset_offset + (sl + StartCellVector[pixel])%1024 ]; + vraw /= drs_gainmean[ Gain_offset + (sl + StartCellVector[pixel])%1024 ]; + vraw *= 1907.35; + vraw -= drs_triggeroffsetmean[ TriggerOffset_offset + sl ]; - for ( unsigned int sl = LeaveOutLeft; sl < RegionOfInterest-LeaveOutRight ; sl++){ - slice_pt = pixel_pt + sl; - //slice_pt_TriggerOffset = pixel_pt_TriggerOffset + sl; - drs_cal_offset = ( sl + StartCellVector[ pixel ] ) % 1024; - cal_pt = pixel_pt + drs_cal_offset; +// slice_pt = pixel_pt + sl; +// drs_cal_offset = ( sl + StartCellVector[ pixel ] ) % RegionOfInterest; +// cal_pt = pixel_pt + drs_cal_offset; +// vraw = AllPixelDataVector[ slice_pt ] * dconv; +// vcal = ( vraw - drs_basemean[ cal_pt ] - drs_triggeroffsetmean[ slice_pt ] ) / drs_gainmean[ cal_pt ]*1907.35; +// destination.push_back(vcal); - vraw = AllPixelDataVector[ slice_pt ] * dconv; - vcal = ( vraw - drs_basemean[ cal_pt ] - drs_triggeroffsetmean[ slice_pt ] ) / drs_gainmean[ cal_pt ]*1907.35; - - destination.push_back(vcal); + destination[sl-LeaveOutLeft] = vraw; }