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Gain stability and the LYSO beam radiation monitor measurements

UiBG. Eigen, E. van der Kraaij, A. Marinov, J. Zalieckas,

Z. Zhou

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Gain Stability Sudies • Analyzing the data taken by E. van der Kraaij in

the period of Feb. 2014– Gain stability of KETEK SiPMs as function of

Temperature.– The noise effect at High temperatures.

Gain is defined as

Distance between 1 pe and 2 pe peaks

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Problems with the Data Quality at high Temperatures

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Gain vs Temp

Analyses made by Jiri Kvasnicka

40

45

45

35

3530…

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Gain Stability Studies

Runs taken with the Adaptive power supply

Runs taken with keithley power supply

50 40 30 20 10 0

0,05

0,06

0,07

0,08

0,09

0,10

0,11

0,12

0,13

Gai

n

Temperature [C]

1,2 pe peak 2,3 pe peak

Analyses where made with tools done by Eric van der Kraaij

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Conclusions

• At high temperatures the data set are affected by the noise

• Possible reason can be, an oscillation of the amplifier observed by Ivo Polak.

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Beam Radiation Monitor• Our task is to build a beam radiation monitor for KLOE at the DaFne experiment in Frascati

• Detector consists of an array of 8 LYSO crystals arranged in a ring around the beam pipe to record beam radiation photons in 100 keV energy range

• Each crystal (dimension: 0.5 x 0.5 x 4 cm3) is wrapped in ESR film and is read out with a KETEK SiPM having an active area of 3 x 3 mm2 with 12100 20 x 20 mm2 pixels (SiPM is not on the market)

• We have tested all 8 crystals and 8 novel KETEK SiPMS using 133Ba, 57Co, 22Na, 137Cs and 60Co sources

– Attach crystals to SiPMs with optical grease (use glue later)– Amplify signal with charge-sensitive preamp AD8000 (gain: 8.5)– Record Signal with 14-bit Caen ADC read out with Labview

• Design of the mechanical support structure requires a visit to Frascati to inspect beam area, as many cables are tied to the beam pipe 30th of June

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LYSO crystal wrapping

Mirror

wrapped in 3 layers of ESR film

Reflector frame

Optimal energy resolution is achieved when we use 3 layers of ESR film as reflector across the surface of the crystal.

Results are shown on next slides

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Test Setup at Bergen University

fADC

Alu Enclosure LYSO crystal

source

KETEK SiPM

Picture of the setup

LYSO crystal 5x5x40 mm

V1729A

10

Improving the Noise/Signal ratio

• Important step before the data taking• Noise reduced when we use double shielding of the AD8000 amplifier and SiPM.• Using a start point grounding avoid ground loops

The output signal from the AD8000 using a Ketek MP204va W8 SiPM. Pulse amplitude is 256mV, Pulse length ~ 200ns, Noise level practically is 0

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Pedestal

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Spectrum Na22511keV

1275keV

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Spectrum Na22

511keV

sE/E=7.3%

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Spectrum Ba133

356keV

81keV

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Spectrum Cs137

661keV

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Energy scale is linear at least up to 1.33 MeV

Co57 -122keV

Na22 – 511keV

Ba133 – 356keV

Cs137 – 661keV

Ba133 – 80keV

Co60 – 1173keV

Co60 – 1332keV

Measured energies of the follow sources•Co57•Co60•Ba133•Na22•Cs137

Na22-1275keV

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The present Readout electronics

2x AD800-

Vb

Ouput

+

• Low noise• Good Dynamic• Stable work

• 450ns Integration time

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Summary

• All 8 crystals are performing very well and they are ready for the DaFne application

• Faster amplifier is under development by Ivo Polak

• Mechanical boxing and support are still under discussions

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Beam Radiation Monitor Time Line

• We have optimized the light collection and tested all SiPMs and 8 crystals all perform well

• Apply final wrapping to 8 LYSO crystals and glue them to a SiPM test performance including time resolution

• Design mechanical support structure after visit to Frascati.

• After completion of mechanical support structure at UiB, we install detector at DaFne and test it with beam- fall 2014

• Write report and publication – End of 2014

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Thank you