AMS DAQ, TRD DSP Software

(1)

AMS DAQ, TRD DSP Software

and

other

Topics

Overview

Arbeitstreffen, Aachen, Jul. 2011 Arbeitstreffen, Aachen, Jul. 2011

(2)

KIT

KIT --IEKPIEKP Karlsruhe

Karlsruhe

AMS on ISS

(3)

KIT

Karlsruhe

ISS Orbit Trapped Particles

Proton Flux >10MeV

(4)

KIT

Karlsruhe

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

(5)

KIT

Karlsruhe

UDR DSP Code Description

(taken from Feb. presentation)

a) Data calibration: pedestal calculation and test of channel

quality

b) Event processing: pedestal subtraction and

zero-suppression, dynamic pedestal calculation

c) DAQ monitoring: Assembly of housekeeping data,

calculation of occupancy and mean amplitude range

(6)

KIT

Karlsruhe

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

(7)

KIT

Karlsruhe

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!)

(8)

KIT

Karlsruhe

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.

(9)

KIT

Karlsruhe

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.)

(10)

KIT

Karlsruhe

TRD DAQ Monitoring

Programs to extract

(11)

KIT

Karlsruhe

UDR DSP Code Test

UDR2 DSP

udsp.c _{(Channels and}Event Data

Amplitudes)

any generated or stored data

Set to sequencer bypass mode

1) Write calibration data 2) Write event raw data and trigger processing

(12)

KIT

Karlsruhe

TRD Data Calibration not at

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!

(13)

KIT

Karlsruhe

Amplitude Spectra

• Equator

• Polar

(14)

KIT

Karlsruhe

Amplitude Spectra

• Equator

• Polar

(15)

KIT

Karlsruhe

Amplitude Spectra

• Equator

• Polar

(16)

KIT

Karlsruhe

SAA RAW Data

(not compressed by DSP)

SAA (uncompressed) Raw Data UDR-0-0 Ch10

100 200 300 400 500 600 700 800 900 1000 ADC pedestal

(17)

KIT

Karlsruhe

UFE overshoot

(18)

KIT

Karlsruhe

2003 overshoot measurement

(19)

KIT

Karlsruhe

Processed RAW SAA data

SAA Event Size

100 150 200 250 300 350 400 e v e n ts iz e ( n b .h it s /UDR) 100 200 300 400 500 600 ADC Half above /below pedestal Ch10

(20)

KIT

Karlsruhe

TRD event size in SAA

(21)

KIT

Karlsruhe

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:

(22)

KIT

Karlsruhe

Final Slide

(23)

KIT

Karlsruhe

backups

(24)

KIT

Karlsruhe

AMS DAQ, TRD DSP Software