AMS DAQ, TRD DSP Software

Transcription

1 AMS DAQ, TRD DSP Software and other Topics Overview Arbeitstreffen, Aachen, Jul Andreas Sabellek IEKP - KIT Campus South Supported by the Carl-Zeiss-Foundation

2 AMS on ISS Realtime position: e.g TRD, Aachen IEKP,Andreas Sabellek p.2

3 ISS Orbit Trapped Particles Proton Flux >10MeV Electron Flux >1MeV TRD, Aachen IEKP,Andreas Sabellek p.3

4 Current AMS DAQ Mode DAQ runs continuously Data Calibration is (manually) made synchronous with orbit to avoid calibration in SAA or polar region DAQ Parameters: Calibration every ~46min around equator crossing TAS Run every ~69min TRD, Aachen IEKP,Andreas Sabellek p.4

5 UDR DSP Code Description KIT - IEKP (taken from Feb. presentation) Three main detector-specific parts: a) Data calibration: pedestal calculation and test of channel quality b) Event processing: pedestal subtraction and zerosuppression, dynamic pedestal calculation c) DAQ monitoring: Assembly of housekeeping data, calculation of occupancy and mean amplitude range TRD, Aachen IEKP,Andreas Sabellek p.5

6 a) Data Calibration Pedestal Calculation Step Initial pedestals for dynamic pedestal calculation Noise Calculation Step Used to reduce hit threshold for quiet channels Channel Quality Check Step Identified bad channels are excluded from correction calculation during DR TRD, Aachen IEKP,Andreas Sabellek p.6

7 b) Event Processing Data processing Subtract pedestal value and common mode Hit detection: Store all amplitudes > 15ADC or 3 sigma for good channels Processing mode parameters for data reduction Variable sigma cut for hit identification (not used) Max and min hit threshold (currently 15 and 9 ADC) Dynamic pedestals (in use!) TRD, Aachen IEKP,Andreas Sabellek p.7

8 Dynamic Pedestal Calculation Algorithm: For every event adjust pedestal for each channel of one of the amplifier chips by +1/8 ADC, if raw value > pedestal value -1/8 ADC, if raw value < pedestal value In this way, the pedestal in any case adjusts to the mean value TRD, Aachen IEKP,Andreas Sabellek p.8

9 c) UDR DAQ Monitoring Calculation Occupancy: During configurable time window (typically 6min), number of hits are counted and then stored in memory Amplitude: The mean amplitude continuously is adjusted by comparison to new hits Allows monitoring of data acquisition without analyzing event data (e.g. data is stuck in network/buffer/etc.) TRD, Aachen IEKP,Andreas Sabellek p.9

10 TRD DAQ Monitoring Programs to extract information from BLOCK-files TRD, Aachen IEKP,Andreas Sabellek p.10

11 UDR DSP Code Test Set to sequencer bypass mode 1) Write calibration data 2) Write event raw data and trigger processing UDR2 DSP any generated or stored data udsp.c Event Data (Channels and Amplitudes) Comparison of results from C code and DSP code. Any data can be fed into processing. C code can also be used to process recorded raw data TRD, Aachen IEKP,Andreas Sabellek p.11

12 TRD Data Calibration not at KIT - IEKP equator Does not effect event data, because - Wrong pedestals are corrected within first seconds by dynamic pedestals - Fixed hit threshold (currently 15ADC) is not effected by noisy calibration - Both is needed, because nobody guarantees calibration at equator! TRD, Aachen IEKP,Andreas Sabellek p.12

13 Amplitude Spectra Equator Polar SAA MPV ~ 50 ADC TRD, Aachen IEKP,Andreas Sabellek p.13

14 Amplitude Spectra Equator Polar SAA looks similar to random trigger TRD, Aachen IEKP,Andreas Sabellek p.14

15 Amplitude Spectra Equator Polar SAA Overshoot dominated pedestals TRD, Aachen IEKP,Andreas Sabellek p.15

16 SAA RAW Data KIT - IEKP (not compressed by DSP) SAA (uncompressed) Raw Data UDR-0-0 Ch10 ADC ~time (s) pedestal TRD, Aachen IEKP,Andreas Sabellek p.16

17 UFE overshoot ~15us ~300us TRD, Aachen IEKP,Andreas Sabellek p.17

18 2003 overshoot measurement TRD, Aachen IEKP,Andreas Sabellek p.18

19 Processed RAW SAA data SAA Event Size Ch eventsize (nb.hits/udr) ADC Half above /below pedestal time (s) TRD, Aachen IEKP,Andreas Sabellek p.19

20 TRD event size in SAA TRD, Aachen IEKP,Andreas Sabellek p.20

21 Polar region Observation 1: event size increases by factor ~2-10 in polar regions Observation 2: tracks together with wide range amplitudes off track Observation 3: Offline analysis shows no change for MPV on track Observation 4: Pedestal is stable TRD, Aachen IEKP,Andreas Sabellek p.21

22 Final Slide TRD, Aachen IEKP,Andreas Sabellek p.22

23 backups TRD, Aachen IEKP,Andreas Sabellek p.23

24 TRD(U) Supply Electronics TRD, Aachen IEKP,Andreas Sabellek p.24