1. December 2005 1 Status of MRS photodiodes ND280 Convener’s Meeting, 9 June 2006 Yury Kudenko INR, Moscow

2. December 2005 2 MRS photodiodes: basic information parameters test results Sci/WLS detectors for SMRD: geometry parameters beam test presented in Physics/0606037 2

3. December 2005 3 MRS APD Manufacturer CPTA, Moscow Sensitive area 1.1 mm 2 Number of pixels 556 Geometrical efficiency 75-80 % Bias voltage range 25-50 V Power consumption 0.025 mW Gain ≤ 10 6 Sensitivity to magnetic field (  4T) no 1.17 mm 3 About 300 devices were tested by now

4. December 2005 4 PDE, cross-talk, dark rate operational voltage 4

5. December 2005 5 Linearity 5

6. December 2005 6 Recovery time t First pulse 50, 100, 300, 600 p.e. 6

7. December 2005 7 Lifetime update 18 MRS diodes were heated for 30 days All showed good stability of l.y. 2 MRS APD 7

8. December 2005 8 About 300 CPTA devices are studied for more than 2.5 years 4 devices are dead: 1 damaged mechanically 1 during temperature test 2 under operation at room temperature Now: 20 photodiodes are under bias voltage for 40 days ALL are OK Devices look very reliable and stable 8

9. December 2005 9 New compact package for MRS diodes MRS APD octagonal Side-to-side 1.17 mm Sensitive area 1.1 mm 2 Package Ceramics Diameter about 4 mm Thickness 1.5–2.0 mm PIN distance 2.5 mm Tolerance 20  m 9

10. December 2005 10 Conclusion & Plan Main parameters: Dark rate (at 0.5 p.e.) ≤ 1MHz (room temperature 22 o C) PDE 10-16 % Long time stability good Temp gradient of PDE (gain corrected) ~ -1.8% Cross talk ≤ 5-6 % Plan: New compact package for MRS diodes is under development at MARS Company (Russia) - INR-CPTA-MARS meeting on 15 June for design and production - First 20 ceramics packages June 2006 - MRS diodes in ceramics July 2006 - Test of MRS diodes in new package August 2006 Design of optical connector depends on new package Several options are under discussion For SMRD detectors - August/September if ceramics OK. 10

11. December 2005 11 SMRD modules with MRS readout (1) One module consists of 4 counters One counter 87 x 17 x 1 ccm Extruded scintillators Bent Y11 WLS fibers Two end readout using MRS APD through optical connectors Package: Two Al bars each with 4 holes for readout Al foil of 300-400 mkm thickness Epoxy glue Should be studied in tests : Parameters Long time stability Temperature effects Fiber/MRS connection, optical isolation Humidity Mechanical performance…. 11

12. December 2005 12 SMRD modules with MRS readout (2) 1 2 3 4 12

13. December 2005 13 SMRD modules with MRS readout (3) 1 2 3 4 13