1. CVD Diamond Sensor Studies for the Beam Calorimeter of the ILC Detector K. Afanaciev 2, I.Emelianchik 2, Ch. Grah 1, E. Kouznetsova 1, W. Lange 1, W. Lohmann 1 1 DESY, Zeuthen 2 NCPHEP, Minsk

2. Beam Calorimeter BeamCal: (4-28) mrad fast beam diagnostics detection and measurement of high energetic electrons and photons at very small angles -- e+e+ e-e- Z0Z0 μ-μ- ~ χ0χ0 μ+μ+ ~ ++ χ0χ0 e + e - e + e -   +  -  σ ~ 10 2 fb (SPS1a) σ ~ 10 6 fb

3. Beam Calorimeter Requirements: Diamond/Tungsten sandwich ~15000 e + e - per BX (30 – 60 TeV) ~10 MGy / year for some area => radiation hard material with small Moliere radius ILC bunch: small size high charge -> beamstrahlung : -> high energy deposition in the Beam Cal:

4. pCVD Sensor Measurements Requirements : - stability under irradiation - linearity of response Measurements : Current-Voltage characteristics Charge Collection Efficiency Qmeas/Qcreated = CCD/L Qcreated(MIP) = 36 eh/mm Irradiation tests (up to 100 Gy) Linearity measurements Samples : Fraunhofer IAF, Element Six 12x12 mm 2, 300-900  m & Gate PA discr delay ADC Sr 90 PM1 PM2 diamond scint.

5. pCVD Sensors Irradiation Measurements: ~ 0.15 Gy/h ~ 0.60 Gy/h ~50%

6. Hadronic beam, 3 & 5 GeV ( CERN PS) Fast extraction mode ~10 4 -10 8 / ~10 ns ADC Diamond (+ PA) Scint.+PMT& signal gate pCVD Sensors linearity test: 10 ns 17 s

7. Linearity test wide intensity range: + absolute intensity measurement ( Thermoluminescence dosimetry) relative intensities estimated from PMT’s: ~(1- 600) HV(PMT) intensity L R

8. PMT calibration

9. Back to the testbeam data… HV(PMT) intensity L R + absolute calibration for one of the runs 1 RI = (27.3+/-2.9) 10 3 MIP/cm 2

10. Linearity of diamond response E64 FAP2

11. The covered range : the particle fluence up to 10 7 MIPs per bunch The obtained deviation from a linear response: ~30% - at the level of systematic errors of the fluence calibration Conclusions