Speaker
Jieh-Wen Tsung
(Universitaet Bonn (DE))
Description
The performance of diamond pixel detectors (single- and poly-crystalline) in high radiation environments is compared to silicon. Estimation of Signal-to-Noise Ratio (SNR) and measurements on real devices with the ATLAS FE-I4 pixel readout chips are presented.
Diamond is an attractive sensor material for vertex detectors because of its strong radiation-resistance. Also, its tiny leakage current after irradiation and smaller capacitance result in low noise. However, silicon can generate larger signals, because its band gap is smaller than for diamond, while its noise level is similar to diamond before irradiation. This situation changes in high radiation environments, e.g. super Large Hadron Collider, at where a particle fluence 10^{16} n_{eq}/cm^{2} is expected. Hence, the SNR of diamond and silicon pixel detectors after strong radiation damage should be compared. For the signals, the decreasing drift distance of charge carriers versus increasing irradiation is measured using diamond pad detectors, and the results are applied to predict the signal deterioration in pixel detectors. For the noise, analytical calculations and simulations using chip design software are used with the leakage current and capacitance to the amplifier of the pixel readout as key parameters. To know the input capacitance, which has never been clearly identified in pixel detectors, a capacitance measuring chip (PixCap) has been developed, so the input capacitance is directly measured. With all the ingredients mentioned above, the SNR of diamond and silicon pixel detectors with respect to increasing radiation damage by neutral and charged particles can be estimated up to 10^{16} particles/cm^{2} fluence. Finally, we present the measurements of diamond and silicon pixel detectors with the ATLAS FE-I4 pixel readout chip. The devices are characterized before and after irradiation, and the measured SNR is compared to the estimation.
Author
Jieh-Wen Tsung
(Universitaet Bonn (DE))
Co-authors
Dr
Fabian Hügging
(Universitaet Bonn (DE))
Prof.
Harris Kagan
(Department of Physics, The Ohio State University, Columbus, Ohio, U.S.A.)
Dr
Michael Karagounis
(Universitaet Bonn (DE))
Mirek Havranek
(Universitaet Bonn (DE))
Prof.
Norbert Wermes
(Universitaet Bonn (DE))
