1. slide 1 Irradiation Study of Single Crystal Diamond Sensors for the PLT Irradiation of sensors at the PS 1.5 years ago Comparison to RD42 irradiated poly and single Re-measured (for a much longer time)  improved CD Upcoming irradiation plan R. Stone--Rutgers RD42 meeting 6-Mar-2009

2. slide 2 Proton Irradiation Jul-07  Irradiated with 24 GeV protons at CERN PS  Contacts were removed prior to irradiation for more rapid cool down  2 diamonds tested for each fluence listed: Fluence (p/cm 2 ) Charge Collection Efficiency 0100% 0.5 x 10 15 62% 1.5x 10 15 32%  For the lifetime of LHC expect: 2.5 x 10 15 p/cm 2 (P. Bhat)  Above results are more pessimistic than those from RD42  Note: the dark current after irradiation is < 10pA

3. slide 3 Before irradiation Signal ( e - ) Single Crystal Diamond Before and After 1.5 X 10 15 p/cm 2 Irradiation After Irradiation Signal ( e - ) Events Pedestal events Pixel thresh

4. CVD Diamond CD vs Proton Fluence slide 4 Fluence (x10 15 p/cm 2 ) Relative CD RD42 Poly PLT old data RD42 Single

5. slide 5 Test of Irradiated Diamond With Fast Electronics  Used BCM_1F frontend electronics (25 ns) instead of standard characterization stand electronics (200 ns) to check if charge collection is slower due to irradiation  Re-tested one of the diamonds that received 1.5 x 10 15 p/cm 2  After calibration, measured collected charge to be <10% lower than slower electronics measurements, but within calibration error and other systematic effects  Also looked at width of signal pulse: –If some charge is collected later than 25 ns, pulse will be wider than unirradiated diamond or calibration signal –No widening was observed on scope pulse (within ~5%)

6. slide 6 Re-measurement of Irradiated Samples One benefit of Fast Amp measurement was a hint at more charge appearing during a much longer measurement period. Can see many rapid jump increases in signal (next plot) Have look so far at 2 out of the 4 irradiated diamonds Expect to see the same effect in the other 2 (starting this month)

7. CD vs Time for Irradiated (1.5 x10 15 p/cm 2 ) Sample slide 7 Time (minutes) CD  500 V | 600V | 1KV | 500V

8. CVD Diamond CD vs Proton Fluence slide 8 Fluence (x10 15 p/cm 2 ) Relative CD RD42 Poly RD42 Single PLT old data PLT new data

9. slide 9 Next  Re-measure other 2 irradiated diamonds, however: –They are currently being repolished to remove surface junk  Send off our 2 re-measured samples for surface cleaning and measure again.  Try using our stronger source for faster (<< 1 week) ‘pumping’  New Irradiation at the PS this summer (Aug-Sep): –8 new samples + 3 pixel planes (bumpbonded ROC+diamond): –Fluences (x10 15 p/cm 2 ) : 4@ 0.5, 2@ 1.0, 4@ 2.0, 2@ 4.0