The The On On bi bit Pe Performance of of DA DAMP MPE Tr Trigger - - PowerPoint PPT Presentation

The The On On‐bi bit Pe Performance of

• f DA

DAMP MPE Tr Trigger Syst System

Yongqiang Zhang, Yang Liu*, Jianhua Guo (DAMPE Collaboration) Purple Mountain Observatory

1 ICRC 2017 Busan, Korea 7/15/2017

Out Outline ine

Introduction to DAMPE Trigger System: Concept & Hardware On‐orbit Performance: Trigger Rate On‐orbit Performance: Calibration & Efficiency Summary

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The The DA DAMP MPE Mission ssion

PSD: Charge measurement, Anti‐coincidence STK: Track reconstruction, Charge measurement BGO: Energy measurement, E‐p separation, Trigger NUD: E‐p separation Launch time : 2015.12.17 Altitude: 500 km Orbit type: solar‐synchronous Orbit period: ~95 min

Motivation: electron, proton, nuclei spectra measurement indirect search of Dark Matter Galaxy gamma ray source

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DA DAMP MPE Tr Trigger Syste System (D (Desig esign Id Idea ea)

Decreasing Trigger rate & Data Size Dead time: 3ms Sub‐triggers:

High Energy Electrons (HE Trigger) Basic e‐p separation Shape of cascade shower Detector Calibration (MIPs & Unbiased) Minimizing Ironizing Particle Unbiased events Gamma ~ 500 MeV (LE Trigger) Lower threshold Electronics Calibration (Periodical) Pedestal 100 GeV e 100 GeV proton

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The The Tr Trigger Syste System (“H (“Hit” Signal) Signal)

14 Layer, 22 BGO/layer 2 side, 3 dynodes readout; Top 4 and Bottom 4 layers, 5, 8 dynode for trigger IDEAS VATA 160: VA: Pre‐amplify, shaping, S/H TA: fast Shaping, Comparator 1 TA process 22 channel, output “or‐ed” as “hit” signal TA signal determining SAA CRD124 W. Jiang et al.

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DM032 C. Feng

The The Tr Trigger Syste System (G (Glo lobal Tr Trigger Signal) Signal)

Logic coincidence on “Hit” signal to generate sub‐trigger Sub‐trigger Pre‐Scaled before Global trigger decision Sub‐trigger : Enable/Disable according to physical requirements Periodical trigger for electronics calibration

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Trigger decision logic of DAMPE

The The Tr Trigger Syste System (T (Trigg rigger Logic) Logic)

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Sub‐trigger Settings L1_P_dy5 denote “Hit” signal of Layer1, P side, dynode 5

DA DAMP MPE Tr Trigger Ra Rate

Trigger rate varies with latitude Pre‐scale suppress the trigger rate SAA, Unbiased and LE trigger rate high.

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Pole Equator

Calibr Calibration ion of

• f Tr

Trigger Thr Threshold shold

Trigger Threshold Calibration MIPs Calibration

9

Layer_4_N8 Layer_4_N8

ICRC 2017 Busan, Korea 7/15/2017

Threshold DM044 S. Wen et al.

Trigger thresholds : important in trigger related study. Calibrate every channel for the thresholds and corresponding energy

Count

Thr Threshold shold .v .vs. Te Temperature

Thresholds has negative correlation with temperature ‐1chn/C°

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Time(Day/Month/Year) Threshold (ADC) Temperature

MC MC‐Da Data Com Comparison arison of

• f Tr

Trigger Efficiency ficiency

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MC: GEANT4 with calibrated thresholds Data: pure electron sample

HE Trigger Efficiency for Electrons MC and Data match quite well

Sum Summar ary

• DAMPE Trigger: energy trigger, energy information from BGO Calorimeter
• Sub‐trigger specialized according to physics motivation, pre‐scaled

to decrease trigger rate.

• Trigger rate varies with particle flux, as expect
• Trigger threshold calibrated, (ADCs) negative relation with T .
• Trigger efficiency for high energy electrons is stable and high.

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