Status of Prototype Preparation and SiPM Characterization W. Baldini on behalf of the Ferrara SuperB Group XIV SuperB General Meeting, Frascati Sept.27 – Oct.1 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

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’ Assembling almost finished: only fibers-SiPM coupling to be done Waiting to have all the SiPM tested: few weeks hopefully

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)

Next and last step: Fiber-SiPM coupling Fibers SiPM Output Connector

Polishing and Aluminization With aluminization No aluminization The surface of the fiber polished with the natural diamond mill have ≈ 20% higher “light transmission” Fiber 1 Diamond mill finishing Single fiber Polishing machine The aluminization on the fiber surface reflects back ≈ 50% of the light

SiPM Characterization

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

SiPM Characterization Received and tested 98 SiPM: 28 1.2x3.2 mm2 (4020) : Good: 23 Bad: 5 (1 no signal, 4 out of position >100mm) 32 1.4x3.8 mm2 (4380) Good: 29 Bad: 3 (1 no signal, 2 out of position) 38 round F=1.4 mm (5550) (Analysis ongoing) Good: 33 Bad: 5 (4 no signal, 1 SiPM out of position) 107 (36-4020, 35-4380, 36-5550) in Perugia now… waiting to be bonded. In total we need (no spare): 126-4020, 128-4380, 53-5550

SiPM-5550: Gain Distribution @ various Vbias voltages

SiPM-5550: Vbias distribution for a fixed Gain The gain has been chosen as the average of the Gain distribution @ 33.0V

Dark count

Selection Criteria Vbias=33V <G> ± 2 σ Good Gain (V/p.e.) Dark Count (Hz) <G> ± 2 σ Good Gain (V/p.e.)