Response of X-UV photodiodes to 1. 5--17. 5 keV x rays and MeV alpha particles

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1144000· OSTI ID:6535542

Wenzel, K W; Li, C; Petrasso, R D; Lo, D H ^[1]; Bautz, M W; Ricker, Jr, G R ^[2]; Hsieh, E ^[3]

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1. MIT Plasma Fusion Center, Cambridge, Massachusetts 02139 (United States)
2. MIT Center for Space Research, Cambridge, Massachusetts 02139 (United States)
3. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

The absolute x-ray response of three X-UV photodiodes was measured over an energy range of 1.5--17.5 keV so that they could be used to calibrate x-ray imaging systems for the ASCA satellite mission. An intense electron-beam x-ray generator was used to test both the dc and ac x-ray response at 1.5, 4.5, 8.0, and 17.5 keV, and an [sup 55]Fe source was used to examine one of the photodiodes at 5.9 keV. The x-ray response was determined by comparing the X-UV diode signal to that of a previously calibrated silicon surface barrier diode (SBD). The X-UV detector response was similar to the SBD response at low energies (1.5 and 4.5 keV). At 8 keV, the X-UV detectors exhibited about 70% of the SBD response, and at 17.5 keV, about 50%. This result is surprising, because the X-UV diodes actually have a greater silicon thickness than the SBD. In contrast to our findings for SBDs in the past, this implies that not the entire physical volume of these detectors comprises the active volume. The X-UV detector x-ray response was also examined as a function of the applied bias voltage. No significant bias voltage dependence of the x-ray signal was found, which indicates that the depletion layer thickness does not determine the active volume either. However, the detector noise was found to decrease substantially as the applied bias was raised from zero to a few volts. Response of these detectors, operated in pulse mode, to [sup 226]Ra [alpha] particles indicated large charge carrier recombination in the bulk silicon. This feature renders these detectors unsuitable for most charged-particle spectroscopy applications.

• DOE Contract Number: FG02-91ER54109
• OSTI ID: 6535542
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 64:7; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

440200* -- Radiation Effects on Instrument Components
Instruments
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46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
47 OTHER INSTRUMENTATION
ALPHA PARTICLES
CALIBRATION
CHARGED PARTICLES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
LAWRENCE LIVERMORE LABORATORY
NATIONAL ORGANIZATIONS
PHOTODIODES
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RADIATIONS
SATELLITES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
US AEC
US DOE
US ERDA
US ORGANIZATIONS
X RADIATION