Introduction
This page is intended to summarise the various calibration types available in the Event Reader, and to show the performance of the calibration types. The table of available calibration types is linked in the left bar.
Timing Calibrations
There are several effects that need to be considered to maximise timing resolution. Firstly, are the intra-channel LABRADOR timing effects (see ANITA ELOG 85 for a more complete discussion)
- Event Unwrapping
- Sampling Rate
- RCO Phase Frequency
- RCO Phase Wrap Epsilon
- Individual Time Bin Widths
There are also inter-channel and inter-SURF effects that need to be considered:
- Signal Propagation (from antennas to SURFs)
- Signal Propagation (inside SURF)
- Trigger Jitter between SURFs
At present the recommended calibration types are kVTFullJWPlusClockZero and kVTFullJWFastPlusClockZero, which try and account for all of these effects. The LABRADOR calibrations come from Jiwoo, the signal propagation was measured (up to the front of the SURF) in Willy Field (see ANITA ELOG 122) and the trigger jitter correction comes either from a fit or zero crossing linear interpolation (see link on left).
Voltage Calibrations
Voltage calibration is necessary to compare the signal strength in different channels. Some of the possible LABRADOR effects are listed below:
- Pedestals (bin by bin)
- ADC to Voltage conversion (LABRADOR chip by chip)
- DC offsets (event by event)
There are also effects exterior to the SURFs which should be considered:
- Antenna Gain
- RF chain response (RFCM's + cables + filters + connections)
The recommended calibrations all use the voltage calibrations that were performed at Willy Field in the pre-flight period (see ANITA ELOG 115) to correct the LABRADOR effects and normalise the RFCM response. Antenna gain is directional and so must be corrected with signal reconstruction. (NB: Although th RFCM response is normalised the overall gain is not corrected for, so the voltage values are still in mV).
Copyright © 2006 Ryan Nichol, (last modified 06 Jun 2007)