DRS4 Corrections#

There are several types of DRS4 corrections, mostly of them are performed by the EventBuilder. We present here a short description, see references [1]-[2] for more details.

Baseline correction#

Each capacitor has a different baseline that must be aligned to a common offset by subtracting a proper ADC shift.

DRS4 baseline correction

Example of baseline counts of individual capacitors for a single pixel [2]#

In short:

  • Input data : dark pedestal events

  • Correction applied by : EventBuilder

  • Coefficient production: see How to

Time-lapse correction#

The baseline of each capacitor depends on the delay from the time of last reading. This is a systematic time shift that must subtracted.

DRS4 time lapse correction

Baseline of capacitors as function of the elapsed time from last reading (dt), before (left) and after time-lapse correction (right).#

  • Input data : dark pedestal events

  • Correction applied by : EventBuilder

  • Coefficient production: see How to

Spikes correction#

R0 waveform presents predictable spikes with maximum height of ~50 ADC that must be subtracted.

DRS4 spikes

Example of waveform with spike and after correction.#

In short:

  • Input data : dark pedestal events

  • Correction applied by : EventBuilder

  • Coefficient production: see How to

Time sampling correction#

The arrival time of a waveform depends (systematically)on the position of the readout window in the DRS4 capacitor ring.

DRS4 time sampling

Example of time shift (in ns) as function of the capacitor number for a given pixel.#

In short:

  • Input data : flat-field events

  • Correction applied by : to be defined

  • Coefficient production: see How to