We have measured the radiation tolerance of poly-crystalline and single-crystalline diamonds grown by the chemical vapor deposition (CVD) process by measuring the charge collected before and after irradiation in a… Click to show full abstract
We have measured the radiation tolerance of poly-crystalline and single-crystalline diamonds grown by the chemical vapor deposition (CVD) process by measuring the charge collected before and after irradiation in a 50 μm pitch strip detector fabricated on each diamond sample. We irradiated one group of sensors with 800 MeV protons, and a second group of sensors with 24 GeV protons, in steps, to (1.34 ± 0.08 × 10$^{16}$) protons cm$^{-2}$ and (1.80 ± 0.18 × 10$^{16}$) protons cm$^{-2}$ respectively. We observe the sum of mean drift paths for electrons and holes for both poly-crystalline CVD diamond and single-crystalline CVD diamond decreases with irradiation fluence from its initial value according to a simple damage curve characterized by a damage constant for each irradiation energy and the irradiation fluence. We find for each irradiation energy the damage constant, for poly-crystalline CVD diamond to be the same within statistical errors as the damage constant for single-crystalline CVD diamond. We find the damage constant for diamond irradiated with 24 GeV protons to be 0.62$^{+0.01}$$_{−0.01}$ (stat) $^{+0.06}$$_{−0.06}$ (syst) × 10$^{-18}$ cm$^{2}$ (p μm) $^{-1}$ and the damage constant for diamond irradiated with 800 MeV protons to be 1.04$^{+0.02}$$_{−0.02}$ (stat) $^{+0.04}$$_{−0.05}$ (syst) × 10$^{-18}$ cm$^{2}$ (p μm) $^{-1}$. Moreover, we observe the FWHM/MP pulse height decreases with fluence for poly-crystalline CVD material and within statistical errors does not change with fluence for single-crystalline CVD material for both 24 GeV proton irradiation and 800 MeV proton irradiation. Finally, we have measured the uniformity of each sample as a function of fluence and observed that for poly-crystalline CVD diamond the samples become more uniform with fluence while for single-crystalline CVD diamond the uniformity does not change with fluence.
               
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