X-ray induced photocurrent characteristics of CVD diamond detectors with different carbon electrodes

Diamond has unique properties which make it suitable for a broad range of radiation detection applications ranging from particle timing and spectroscopy, to neutron, UV and X-ray sensors. In X-ray dosimetry, the atomic number of diamond (Z = 6) close to that of the human tissues (Z = 7.42) allows to mimic the real absorbed dose avoiding off-line recalculations. Moreover, its low atomic number and the capability to withstand high radiation fluxes make possible its use as beam monitor without altering significantly the properties of the interacting beam. To preserve the tissue equivalence of the diamond and minimize the perturbation and absorption of the incident beam, diamond detectors based on low thickness and low atomic number electrodes become a requirement. In this paper we present the X-ray detection characteristics of electronic grade CVD diamond sensors prepared in house with thin amorphous carbon electrodes fabricated by Pulsed Laser Deposition (PLD) technique in the fluence range of 2.3 – 3.6 J∙cm -2 . The devices showed a linear dependence of the induced photocurrent respect to the dose rate. Also, best dynamic response and better stability of the signals were achieved for applied bias up to ±50 V with signal to noise ratio (SNR) of ~300.