Prototype Assemblying, SiPM Characterization and QC W. Baldini on behalf of the Ferrara SuperB Group XV SuperB General Meeting, Caltech Dec.14-18 2010

The IFR Prototype The Prototype

The IFR Prototype The Iron is on Its way to Fermilab Iron Active Layers (Pizza Boxes) The Iron is on Its way to Fermilab Iron Iron: 60x60x92 cm3 , 9 slots for the active layers 8-9 active layers readout together 4 Time readout (TDC-RO) “standard “ 4 Binary Readout (BiRo) “standard” 4 special modules to study different fibers or SiPM geometry

Prototype assembling

Active Layers: the Pizza Boxes Pizza box #1: TDC-standard (fibers Bicron-1.0mm, SiPM 1.2x3.2 mm2 - 4020) Pizza box #2: TDC-standard Pizza box #3: TDC-standard Pizza box #4: TDC-standard Pizza box #5: TDC Special fibers 1.2mm Pizza box #6: TDC Special round SiPM Pizza box #7: TDC Special MPPC Pizza box #8: BiRo Standard (fibers Kuraray 1.2mm, SiPM 1.4x3.8 mm2 - 4380) Pizza box #9: BiRo Standard Pizza box #10: BiRo Standard Pizza box #11: BiRo Standard Pizza box #12: BiRo Special Round SiPM Menu’

Pizza boxes Assembling Prepare the supports and place the scintillator bars Pizza boxes Assembling fibers positioning Put silicone Sealant to fix fibers and keep optical glue inside the embedded holes

Labeling and collecting the fibers around the supports Fill the machined grooves with optical grease and cover it with stripes of reflecting aluminum (BiRo only) Fill with optical glue the embedded holes Put double-side adhesive to fix the second layer (BiRo only)

Aluminum tape Aluminum on the not-readout end of the fibers Positioning of the second layer of scintillators (BiRo) Sputtering (on 1 pizza box)

Fiber-SiPM coupling Fibers SiPM Output Connector

Local test with cosmics All the active layers have been assembles ad locally tested with cosmics The test was very fast (not much time left before the shipping to Fermilab) We performed a rate vs Threshold scan, from 4.5 p.e. up to 10.5 p.e. for each channel of the pizza box, looking for a “plateau” around the expected cosmic rate: ≈ 2Hz This test was basically done to check the functioning of the SiPM and could not give any efficiency or time resolution estimate This parameters are being measured thanks to the testbeam data

Local test with cosmics Rate (Hz) Rate (Hz) Vbias Pizza Box Channel Rate (Hz) Vbias Roughly the expected rate Pizza Box Channel Thr (p.e.)

SiPM Characterization

SiPM Characterization three types of SiPM tested: 1.2x3.2 mm2 (type 4020), to be coupled to 1.0mm fibers (3 fibers), total 126 needed, 171 characterized 1.4x3.8 mm2 (type 4380), for 1.2mm fibers, 128 needed, 172 characterized array of 3 round sensors: f=1.4mm, for both 1.0mm and 1.2 mm fibers, 53 needed, 94 characterized

SiPM Characterization summary Received and tested 437 SiPM: 171 1.2x3.2 mm2 (4020) : Good: 160 Bad: 11 (no signal) Yield: 93.6% 172 1.4x3.8 mm2 (4380) Good: 166 Bad: 6 Yield: 96.5% 94 round F=1.4 mm (5550) Good: 84 Bad: 10 Yield: 89.4%

SiPM Selection

SiPM Selection Custom software (Labview) has been developed Acquires noise distributions (tipically 15000 events ) Fit distributions with 2 gaussians (1 p.e., 2 p.e) and calculate G Plot/fit G vs Vbias and 0.5 p.e. threshold vs Vbias

For each SiPM we measure 4 paramenters: mG, qG G vs Vbias linear fit parameters mth, qth Thr(0.5p.e) vs Vbias linear fit parameters From the above parameters we calculate the working Vbias voltage for a chosen Gain: G = mG* Vbias + qG  Vbias = (G-qG)/mG and the corresponding thresholds: 0.5p.e. = mth*Vbias + qth Th (n*p.e.) = Th(0.5p.e.) + n * G with the above paramenters we can set each SiPM at the desired working point (Gain, Thr) Since we equalize the Gain, the dark count could be very different from each other

1 p.e. 2 p.e. G Noise Spectra We measure Gain and Dark Count Rate vs Vbias and select the most homogeneous devices for each type 0.5 p.e. G vs Vbias

SiPM Selection Dark Count (Hz) Vbias=33V, th=2.5 p.e. Spares Selected G>15 mV/p.e. Spares DC< 200 KHz Selected Gain (V/p.e.)

Parameters comparison Vbias = 33.0V , Thr = 2.5 p.e. Ratio DC/G among the three types: 4020: <DC/G> = 4.1 x 106 Hz*p.e./mV 4380: <DC/G> = 5.9 x 106 Hz*p.e./mV 5550: <DC/G> = 6.6 x 106 Hz*p.e./mV Ratio DC/Area: 4020: 2.21 x 104 Hz/mm2 (area = 3.84 mm2 ) 4380: 1.48 x 104 Hz/mm2 (area = 5.32 mm2 ) 5550: 2.73 x 104 Hz/mm2 (area = 4.62 mm2)

Conclusions The assembly of the 12 active layers was completed on Nov 3-rd The local cosmics tests were completed on Nov 8-th (the shipping was foreseen on Nov 9-th…) Not enough time to perform extensive tests before the testbeam... First “impressions” from testbeam were encouraging (online monitor showed a good behaviour) Efficiency and time resolution studies are ongoing with testbeam data