Performance of LYSO and CeBr3 crystals readout by SiPM arrays as compact detectors for space based application Abaz Kryemadhi, Messiah College, PA,US IPRD2016, Siena, IT, Oct 3-6, 2016 Acknowledgment: NASA Pennsylvania Space Grant Consortium IPRD2016 Siena

Physics Motivation New physics searches from cosmic rays to gamma rays and particle dark matter in space can greatly benefit from compact detectors with good energy and angular resolution Multi-segmented EM Calorimeter with minimal dead space Low voltage and power consumption Ability to withstand take off conditions Linearity and uniformity response in energy range in consideration IPRD2016 Siena

Crystals Shower Containment LYSO CeBr3 Density (g/cm3 ) 7.4 5.10 Radiation Length(cm) 1.14 1.96 Moliere Radius (cm) 2.07 2.97 Interaction Length (cm) 20.9 31.5 Peak Wavelength (nm) 402 370 Decay Time (ns) 40 17 Light Yield %NaI(Ti) 85 122 Time and Energy Resolution, Also reduction of pile-up IPRD2016 Siena

Introduction to Silicon Photomultipliers (SiPMs) Reverse biased avalanche photodiode Operated at few volt above the breakdown voltage Each microcell is a binary device SensL IPRD2016 Siena

Introduction to Silicon Photomultipliers (SiPMs) Immune to magnetic fields Can be combined to form a large reading array This array number of microcells ~80,000 Sensl: ArrayC30035-16P-PCB High PDE >40% at peak Dark rate <30 kHz/mm2 Operating voltage <30 V Temperature Drift ~20 mV/0C IPRD2016 Siena

Introduction to Silicon Photomultipliers (SiPMs) Gain of order of 106 comparable to PMT No Need for sophisticated amplification circuitry Dark Rate increases with overvoltage and temperature For high energy physics not a big concern, set higher photo-electron threshold Saturation of microcells however could limit the dynamic range IPRD2016 Siena

Sensl 4x4 Array Readout Current Limiter 100nF 10nF 1nF - 50  10nF DC + To 50 Ohm DRS4 Evaluation DAQ SiPM Array AC Noise Frequency Filter AC coupling IPRD2016 Siena

LYSO (left) and Cerium Bromide (right) crystals LYSO Crystal developed from EPIC Crystal (16 mm x 16 mm x 40 mm) Sensl ArrayC and the Readout Board LYSO (left) and Cerium Bromide (right) crystals CeBr3 Crystal purchased from Berkeley Nucleonics and made from Sionix Holland (13 mm x 13 mm x 13 mm) DAQ, Digitizier: DRS4 Evaluation Board developed by Stefan Ritt, Paul Scherrer Institute Silicon Photomultiplier

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Linear in Gamma Ray Energy Range Expected to deviate for wider dynamic range Neutral density filters needed for higher energy   IPRD2016 Siena

Small deviation observed Expected to deviate for wider dynamic range, Saturation function needs to be applied   IPRD2016 Siena

Uniformity 25 mm Tungsten Collimator, Small Aperture, scan across length of crystal No trends observed in energy resolution Light yield not affected for these size crystals, self-absorption not an issue IPRD2016 Siena

Time Resolution Study Coincidence Resolving Time Note: Circuit not optimized for timing studies Timing studies were not affected by having a collimated source versus an un-collimated IPRD2016 Siena

Best Timing Achieved by using the fast rise time Close to baseline Less effected by Recovery Time Constant Recovery time constant = Cd( Rq + N * P * Rs)   Cd = microcell diode capacitance (180 fF) Rq = microcell quench resistance (360 kohms) N = number of microcells (4774) P = number of SiPM pixels in summed array (16) Rs = external series resistance SensL Private Communication IPRD2016 Siena

Time Resolution Sub-nanosecond coincidence resolving time, best timing is picked from the arrival of the early photons as expected. Good timing important for triggering, event processing and angular resolution CRT=660 ps @ 2% CFD IPRD2016 Siena

Summary A simple readout for the Sensl SiPM 4x4 array was presented Both LYSO and CeBr3 mostly linear in gamma ray energies and good energy resolution The prospect for use in space is very good, as a multi-segmented EM Calorimeter Cost is however an issue, anticipate reduction due to large production for medical applications Next A mini-calorimeter to be tested at Fermi National Laboratory Test-Beam IPRD2016 Siena