Status of Prototype Preparation (I) Wander Baldini On behalf of the Ferrara SuperB group SuperB Workshop, LNF Dic. 2-nd 2009

Prototype General Structure Active area: 60x60cm 2 8 Active Layers gap = 2.5cm to house the active layers 4 “Time Readout” modules 4 “Binary Readout” modules 2

Time Readout Module 5 Modules to be built (4 +1 spare) Scintillator: –Dimensions: 2x4x60 cm 3 –15 bars/module  Total of 5x15 = 75 bars Fibers: – ϕ =1.0mm – Bicron BCF92, Length =4.0m –3 fib./bar x 15 bars x 4m = 180m/module  Total = 900m SiPM: –Dimensions: 1.2x3.2 mm 2 (3.84 mm 2 ) –15 bars x 2-ends-readout = 30 SiPM/module  Total of 150 SiPM 3

Binary Readout Module 5 Modules to be built (4 +1 spare) Scintillator: –Dimensions: - Horizontal bars: 1x4x60cm, 15 bars/module  Total of 75 bars - Vertical bars: 1x4x45 * cm, 15 bars/module  Total of 75 bars Fibers: – ϕ =1.2mm – Kuraray Y11(300), Length =2.0m –3 fib./bar x 30 bars x 2m = 180m/module  Total = 900m SiPM: –Dimensions: 1.4x3.8 mm 2 (5.32 mm 2 ) –30 bars x 1-end-readout = 30 SiPM/module  Total of 150 SiPM 4 * We need to leave some space to allow the fibers exit

Other options: Fibers: also ϕ =1.2mm Bicron fibers are available. –We would have more light and so better efficiency and time resolution –We’d have to use bigger SiPM so more noise… –To be evaluated with the prototype SiPM: –Dimensions: array of 3 circles ϕ =1.4mm connected in parallel –Lower surface: 4.6mm 2 –Same type for both layouts –Allow some distance among fibers  make the mechanics easier –To be better understood/defined with FBK people 5

6 Only horizontal scintillator bars (60cm) Only horizontal scintillator bars (60cm) Readout of both ends of the fibers Readout of both ends of the fibers Fibers 4m long collected on two 20cm spools on each side Fibers 4m long collected on two 20cm spools on each side SiPM cards fixed on the two sides SiPM cards fixed on the two sides “Pizza boxes” Module Structure: Time Readout

7 Both: horizontal (60cm) and vertical (45-50cm) scintillator bars Both: horizontal (60cm) and vertical (45-50cm) scintillator bars Readout of only one end of the fiber Readout of only one end of the fiber Fibers 2m long collected on 20cm spools Fibers 2m long collected on 20cm spools SiPM cards fixed on the two sides (left: horizontal, right: vertical) SiPM cards fixed on the two sides (left: horizontal, right: vertical) “Pizza boxes” Module Structure: Binary Readout

Fibers-SiPM Coupling 8 SiPM bonded directly on custom made SiPM bonded directly on custom made PCBs: SiPM-card PCBs: SiPM-card SiPM-card is fixed on the external sides of SiPM-card is fixed on the external sides of the pizza box the pizza box The SiPM-card brings the signal from SiPM The SiPM-card brings the signal from SiPM to an external coaxial connector to an external coaxial connector Fibers are glued on the support and kept at about 0.1 mm from the SiPM surface Fibers are glued on the support and kept at about 0.1 mm from the SiPM surface It’s important not to touch also the very fragile bonding wires It’s important not to touch also the very fragile bonding wires Detailed design under definition Detailed design under definition

Fiber Polishing Polishing of the fiber surface is very important to optimize the light transmission to SiPM, we are considering 2 options: Single fiber polishing: –Simpler and we have in Ferrara a “Single fiber polishing machine” but… it’s rather old and we do not have any spare part –To be done on ~ 1000 fiber ends –It’s difficult to precisely align the 3 fibers on the SiPM surface Three fibers polishing: –Glue the 3 fibers on the fibers holder (see previous slide) and make the polishing of the 3 fibers all together –In this case the fibers alignment would be optimal –Needs some tests to ensure the required “smoothness” of the fibers surface (milling speed, type of mill…) 9

Status of the orders Fibers ordered: –Bicron (Saint-Gobain) BCF92: 1000m ϕ =1.0mm (~ 160m already in Ferrara) 500m ϕ =1.2mm –Kuraray Y11(300): 1800m ϕ =1.2mm (250m already in Ferrara) SiPM: placed the order for a production (10-15 wafers), to speed up the production we share it with Perugia (G.Ambrosi) –3 geometries: x 3.2 mm 2 for Time readout (fibers 1.0mm) x 3.8 mm 2 for Binary Readout (fibers 1.2mm) 3.Array of 3 circles ϕ =1.4mm –Available area: ≥18cm 2 /wafer, exact numbers of SiPM depends on how packed they could be. It will be defined in the next days –At least twice of what it’s needed for the baseline geometries 1. and 2. ( ) –Bonding and coating to be done in Perugia (they have already done many for FBK) 10