(1)Thin scintillating fibers coupled to SiPMs for fast beam monitoring and timing purposes

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(1)Thin scintillating fibers coupled to SiPMs for fast beam monitoring and timing purposes. Giada Rutar on behalf of the MEG and Mu3e Collaborations Paul Scherrer Institute and ETH Zurich, Switzerland. Achievements. Objective Target. μm2 size,. Development of detectors based on thin scintillating fibers (250 x 250 smallest size available on the market) and SiPMs for:. ² Efficiencies for Minimum Ionizing Particles AND/OR logic: Both SiPM/ at least one SiPM connected to a fiber see at least one photon (threshold at 0.5 NPhe). ² Vertex tagging (MEG: Active TARget) ² Beam monitoring (MEG, beamlines @ PSI in general) ² Timing purposes (Mu3e scintillating fiber hodoscope) Versatile, modular and comparably cheap technology, applicable in magnetic fields and vacuum environments. Challenge: Ability to detect minimum ionizing particles with high efficiency using so little scintillating material (expected energy deposit O(50 keV) / fiber O(10 detected photons)/ fiber).. Single fiber. Double layer. Triple layer. AND. (72 ± 2) %. (89 ± 2) %. (95 ± 2) %. OR. (96 ± 2) %. (99 ± 2) %. (98 ± 2) %. Events. ~ 700 µm Mylar equivalent. 20. 50. 52. 54. 56. Package 58 60 62 Window V. bias. 2.2 2.4 2.6 2.8. 3. 1.3x1.3. 3.0x3.0. 667. Vover [V]. -6050CS. -1350PE. 6.0x6.0. 1.3x1.3. 3600. CTP [%]. 7. -3050PE 3. 0. 5. 10. Ceramic 15. 14400 20. mm. 667. 3600. 14400. 25. 30. Surface mount type 35. T [°C]Epoxy resin. 1.41. 2. -. 2.5. 3. 3.5. -. 0.2 15 0 10. −0.2 −0.4. 5. −0.6 −0.5. 0. 0.5. 0. 4. 4.5. 20. Simulated distribution of photons originating from a 250 μm fiber centered on a SiPM active area of 1.3x1.3 mm2. Shifts of up to 300 μm affordable without any light loss.. μ, e, π. pe = 115 MeV/c. run0302- Sr90- Arrayx4 -Alcoating 30nm. ×10. 10 8. 4. with Al coating. 14 12. 200 10. 150. CT ≈ 30%. 6. 3. 250. w/o Al coating. 12. 100 4. 50. 0. 400. ×10. σ(T) ≈ 575 ps. 2. 100. (core fraction 80%). 3. 500. 300. 200. combined offline. Note: Three layers of 250 μm fibers are equivalent to < 0.3 % Χ0 ² Stand-alone Monte Carlo Simulation based on Geant4 and custom SiPM simulation.. 500. CT < 1%. 6. 2. 600. 8. 1400. 0. 1200. −500. 1000. −1000. 800. −1500. 600. signal (discharge prob. and pixel recovery) photoelectrons (quantum efficiency). 0. 0. 2. 4. 6. 8. 10. 12. 14. 0. 0. 2. 4. 6. NPhe1. 8. 10. 12. 14. 0. simulated waveform. −2500 0. 50. 100. 150. 200. t [ns]. Fiber mounting. SiPM alignment. photons on sensitive SiPM area (fill factor). NPhe1. −2000. Fiber coating. defocused beam. Three Combined Fibers. <N> ≈ 11 NPhe. Crosstalk between adjacent fibers 14. shifted beam. ² Array Configuration: Light Yield and Timing Resolution Custom waveform analysis with offline constant fraction discrimination (threshold at 0.5 NPhe, AND logic). trigger. 1. x [mm]. Fiber selection. 15. 5. Vover [V]. -. NPhe2. 20. 10. -. 1.55. NPhe2. y [mm]. 750 μm. π+ µ+. %. 1. Large Prototype 32 fibers arranged in four layers and read out indivdually by SiPMs on both fiber ends Key points: ² Fiber quality control (geometry and visible defects) ² Aluminum coating (100 nm) around every fiber to reduce fiber crosstalk < 1% ² Glueing of fibers to layers of uniform thickness of ca. 265270 μm ² Mechanics for individual fiber readout guaranteeing a good fiber – SiPM alignment. 0.4. 0. Grid made of two layers (x,y) à 21 fibers of 250 µm size each, covering an area of 10x10 cm2 • Pitch: 5 mm; Fiber Length: ca. 20 cm • 84 channels (every fiber read out on both ends) • Trigger + DAQ: WaveDREAM boards (waveform digitizer running @ 2 GHz), dedicated trigger system (MEGII) Quasi non-invasive, fast, capable of particle ID. standard. 2. μm. 2. Silicone resin. [V]. 6.0x6.0. Prototype Construction. 25. 20. Unit. -6050PE. 3.0x3.0. 74. Window refractive index. 0.6. 15. 4. S13360. 3.2 3.4 3.6 3.8. -3050CS. 50. 64. 10. TOFfiber [ns]. 5. Events (norm.). 2. -1350CS. Geometrical fill factor 48. 5. 5. 0 1.8. Number of pixels / channel 20. 46. 0 0. 40. Pixel pitch. 44. e+. 3000. crosstalk probability. 6. 60. 40 Effective photosensitive area. 1. 60. 80. 20. 60. 80. •. Events. 8° C 20° C 32° C. Parameters. Dark count rate [kHz]. I [nA]. Dark count rate [kHz]. Structure. 10. 80. 100. Measurements show good agreement (within better than 10 %) with the standard beam measurement device (pill counter) for both rates and beam sizes.. Graph new. 120. TOFfiber [ns]. ² Beam Monitoring Tool. 6. dark count rate. 140. 40. 0 0. 2. Fluorescence measurement Flow cytometry 180 8° C DNA sequencer 160 120 Environmental analysis 140 20° C 120 32° C PET 100 100experiment High energy physics. 160. 5. 1000. A.U.. 5. 94327 7.568 10.71 3.469 5.772. tof2__1 Entries 94277 Mean 4.786 Std Dev 2.271. 15. 2000. avalanche photodiode and a quenching resistor. Pixels are connected in parallel and Overview The S13360 series are the MPPCs for the precision arranged in a rectangular manner. measurements. The strongest point of these MPPCs is reduced cross talk and after pulses compared Advantages w.r.t todrastically photomultiplier tubes: to our previous products. By widening the operating Hamamatsu voltage range and improving the time resolution and ² insensitive to magnetic photon detectionfields efficiency, the S13360 series offer the 13360-1350CS characteristics needed for a variety of applications. ² relatively low HV supply These MPPCs have a photosensitive area of 1.3 × 1.3 mm , 3.0 × 3.0 mm , 6.0 × 6.0 mm , and are available ² competitive photon detection efficiency (30-40 %) in a ceramic package or surface mount type package. SiPMs used here: Hamamatsu 13360-1350CS and 12825-050C - 50 μm pixel size, Features Significantly 2. reduced cross talk and after pulse active area 1.3x1.3 mm Very compact package with small dead space Superior photon counting capability Detailed characterization properties (dark count rate, optical crosstalk Low voltageof (V important =53V Typ.) operation High gain: 10 to 10 probability, gain etc.) as a function of temperature and bias voltage Application. h Entries Mean x Mean y Std Dev x Std Dev y. 25. 20. 4000. Silicon PhotoMultipliers. BR. 30. 10. MPPC® (multi-pixel photon counter) S13360-1350CS, S13360-1350PE („Multi-Pixel Photon Counters“) S13360-3050CS, S13360-3050PE S13360-6050CS, Pixelized single photon countingS13360-6050PE devices, where every pixel consists of a Geiger. 2. 6000 5000. 2015.01 KSX-I50072-E_S13360-1350 Series. 2. NPhe. charge.ch5*1.75-0.2+charge.ch6*1.4-0.2:fmod((time_2points.ch5+time_2points.ch6)/2-fmod(time.ch3,19.75)-8,19.75) {charge.ch5>0.3&&charge.ch6>0.3&&time_2points.ch5>0&&time_2points.ch6>0&&outside.ch5==0&&outside.ch6==0&&time_2points.ch5<60&&time_2points.ch6<60&&fmod((time_2points.ch5+time_2points.ch6)/2-fmod(time.ch3,19.75)-8,19.75)<7.1}. ² Saint-Gobain BCF-12 squared multiclad fibers ² Squared: Higher trapping efficiency (7.3%) compared to round fibers (5.6%) ² Emission color peaks in the blue (where the photon detection efficiency of the SiPM is approximately maximal) ² Attenuation length L > 2.7 m ² Aluminum coating around every single fiber (two methods investigated: Physical Vapor Deposition (CERN) and sputtering (PSI)) ² Coupling to SiPMs by optical grease. I-V curves. e+. ² Particle ID through charge discrimination and time-of-flight p = 28 MeV/c p = 115 MeV/c ~ 500 µm Mylar equivalent 7000. Scintillating Fibers. 10 2. AND logic. 200 0 0. 10. 20. 30. charge spectrum. 0.014. 0.012. 0.01. data MC. 0.008 0.006. photons exiting the fiber. 400. 0.016. 0.004. 0.002. 40. ph|phe. 0. 0. 5. 10. 15. 20. References ² A. Stoykov, R. Scheuermann, K. Sedlak, NIMA 695 (2012) 202 ² A. Papa, F. Barchetti, F. Gray, E. Ripiccini, G. Rutar, NIMA 787 (2015) 130 ² A. Papa, P.-R. Kettle, E. Ripiccini, G. Rutar, NIMA 824 (2016) 128. Physics of Fundamental Symmetries and Interactions - PSI2016. 25. 30. Nphe.

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