Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

SPI - ACS EM SPI - ACS EM Scientific MeasurementsScientific Measurements

August 19 - September 4, 1998

at DSS (Friedrichshafen)

A. v. Kienlin, R. Georgii, C. Wunderer

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

OverviewOverview

• ACS EM configuration for scientific measurements• Results

– Linearity and Calibration of Energy and Event Thresholds• Single Photoelectron Spectrum

• Gamma-ray Line Spectra

– Processing Times and Jitter

– Overrange Signals, overall ACS rate monitor (“burst mode”)

– Problems encountered

• SPI Documents: SPI-MPE-PL-12-22 (Plan)SPI-MPE-RP-12-26 (Report, in preparation)

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

AC

S E

MA

CS

EM

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

ACS EM Configuration for ACS EM Configuration for scientific measurements (I)scientific measurements (I)

• 1 BGO detector module• 2 PMTs

• 1 BGO crystal, consisting of 2 crystal blocks glued together, total dimensions 1.6 5 8 cm3

• 1 LED dummy• 2 PMTs

• 3 LEDs for generation of single photoelectrons (SPE), lower energy and overrange events

• 1 RC circuit (“charge box”) for precise charge injection to CSA input of FEE U Q

R

C

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

LED-DummyLED-Dummy

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

BGO Crystal Detector ModuleBGO Crystal Detector Module

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

ACS EM Configuration for ACS EM Configuration for scientific measurements (II)scientific measurements (II)

• 1 FEE with CSA output connector (“reference FEE”)(not officially part of ACS EM)

• FEE Unit Tester (FEE-UT)

• 2 FEEs • EMC representative ACS EM with VCU• VCU Unit Tester (VCU-UT)

all 3 FEEs: design status MARCH 1998

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

FEE-Unit Tester FEE-Unit Tester with FEE and LED-Dummywith FEE and LED-Dummy

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

VCU - Unit TesterVCU - Unit Tester

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Linearity of Linearity of Event-Trigger ThresholdsEvent-Trigger Thresholds

0 5 10 15 20 25 30 350

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Schw

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(m

V)

Event Trigger Level

Event Trigger LiniaritätEn=0; HV=13100 Hz24.8.98 14:45

Y =14,60051+14,54792 X; R=0.99993

Y =8,55803+15,53954 X-0,02664 X2; R=0.99999

Schwelle EVLin10Sc EVLin10Sc

0,0

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roxim

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toe

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Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Linearity of Energy ThresholdsLinearity of Energy Thresholds

-10 0 10 20 30 40 50 60 70

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EnergietriggereichungEv=6; HV=13; 20s@100Hz26.8.98 15:30

Sch

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mV

]

Energy Threshold Level

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(ap

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/10

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Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Generation of Differential SpectraGeneration of Differential Spectra

• Measure number of counts per 5 sec for each energy or event-trigger threshold setting

• This „Stepping Method“ yields integral energy spectra (counts above threshold)

• Differentiate to obtain energy spectra (counts per channel)

0 5 10 15 20 25 30 35

-100

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Differentielles Spektrum EM-F8Single Photoelectrons from LED 10x730,0A

Cou

nts/

Cha

nnel

Event Trigger Level

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Messung EM-F8Integral Spectrum Single Photoelectrons from LED

Cou

nts

Event Trigger Level

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Single Photoelectron (SPE) SpectrumSingle Photoelectron (SPE) Spectrumusing LED Dummyusing LED Dummy

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700 Differential Spectrum EM-F8

Data: EMF8_mean'Model: GaussAmpChi^2 = 9.54289xc 18.41075 ±0.31471w 7.50047 ±0.34831

Co

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ha

nn

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Event Trigger Level

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ha

nn

el

Event Trigger Level

PMT : HV nominal (1129 V)

HV low (1088 V)

HV high (1170 V)

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Single Photoelectron MeasurementsSingle Photoelectron Measurements• Using

– FEE event-trigger threshold calibration (knowledge of charge at CSA input corresponding to an event-trigger level)

– knowledge of PMT gains at different HVsobserved peaks correspond to 1.7 x 10-19 ( 0.3 x 10-19) Cb

generated at photocathode

• SPE spectrum from LED with a different FEE corresponds to 2.0x10-19 ( 0.3 x10-19) Cb

results consistent with expected values (single photoelectrons!)

!! So far SPEs measured only using LED Dummy !!

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Ab hier „Reservefolien“Ab hier „Reservefolien“

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

Detail ACS EMDetail ACS EMLED-Dummy and „Crystal Dummy“LED-Dummy and „Crystal Dummy“

Cornelia Wunderer, MPE SPI-Team Meeting, Paris, 7.-9.10.98 SPI-ACS EM Measurements

LED - SPE Spectrum measured LED - SPE Spectrum measured automatically using VCU-UT automatically using VCU-UT

programprogram

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500Messung 09032007Single Photoelectrons from LEDFEE 06 (SN 003)

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tial C

ount

s

Event Trigger Level