X-ray 2D array detectors based on polycrystalline diamond have been fabricated and tested in the dark and under low energy X-ray beams, as well as under UV laser pulses. Depending on the metallic contacts distance or crossover-area, each pixel exhibit low dark current values down to 2 pA and light to dark current ratio as large as 20 when biased at 50 V. The intensity dependence of X-ray photocurrent, as measured for different thickness of Al absorbers, changes according the square root of the beam intensity, thereby suggesting a good crystalline quality of the used diamond slab. A similar behaviour is found when UV laser pulses of high energy are used for device irradiation. At lower energies, a larger photocurrent change with the beam intensity is found, eventually becoming a linear dependence. Such a result confirms the expected good diamond sample quality and suggests a device use for X-ray beam profiler with a large dynamics. The diamond sample and detector uniformity has been also tested under UV laser pulses. The observed pixel response uniformity further support the possible device application as image sensor
Ciancaglioni, I., Rossi, M.C., Mazzeo, G., Conte, G. (2004). X ray diamond 2D array. In 2004 IEEE Nuclear Science Symposium Conference Record.
X ray diamond 2D array
ROSSI, Maria Cristina;Conte, G.
2004-01-01
Abstract
X-ray 2D array detectors based on polycrystalline diamond have been fabricated and tested in the dark and under low energy X-ray beams, as well as under UV laser pulses. Depending on the metallic contacts distance or crossover-area, each pixel exhibit low dark current values down to 2 pA and light to dark current ratio as large as 20 when biased at 50 V. The intensity dependence of X-ray photocurrent, as measured for different thickness of Al absorbers, changes according the square root of the beam intensity, thereby suggesting a good crystalline quality of the used diamond slab. A similar behaviour is found when UV laser pulses of high energy are used for device irradiation. At lower energies, a larger photocurrent change with the beam intensity is found, eventually becoming a linear dependence. Such a result confirms the expected good diamond sample quality and suggests a device use for X-ray beam profiler with a large dynamics. The diamond sample and detector uniformity has been also tested under UV laser pulses. The observed pixel response uniformity further support the possible device application as image sensorI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
