PHOTOVOLTAIC RESPONSE OF SELENIUM BARRIER LAYER CELLS TO X-RADIATION IN THE ENERGY RANGE OF 15-40 KEV
Twenty selenium barrier layer cells were irradiated with 15 to 40 kev x rays, and their behavior was compared with their response to light. The x-ray sensitivity is independent of intensity at constant anode voltage, but linearly proportional to anode voltage at constant anode current. The fonm of transient response to x irradiation depends on the intensity of irradiation and the previous history of cell irradiation, a time of rest of about 2 hours being required to achieve the "first-irradiation" response. The fatigue effect does not occur in the steady-state values to photovoltage and photocurrent. There is some evidence for a qualitative relationship between x-ray and optical Photovoltage sensitivities of a cell, but there is no relationship between the photocurrent sensitivities. (auth) The ionization produced in a dielectric by gamma -irradiation causes an increase in electrical conductivity of sigma /sub T/ = en mu , where sigma /sub T/ is the radiation electrical conductivity, e is the elementary charge, n is the concentration of charge carriers and mu is the mobility. The value of or is directly proportional to the radiation intensity Y for such materials as quartz, sulfur, polyethylene and ceramics in which electron traps are formed. In this case the number of ion pairs fonmed by irradiation per cm/sup 3/ per sec is g = bY = beta (N + N/sub t/), where beta is the recombination coefficient, Ni is the concentration of traps at steady state, N is the concentration of free electrons at steady state, and b is a term directly proportional to the gamma -ray absorption coefficient. If Ni>> N, it can be shown that sigma , = e mu bY/ beta Ni = aY. It can be assumed that free electrons are generated only by the gamma -irradiation, while electrons are destroyed by recombination with posi-tive ions and by capture by means of the traps. It is shown that if trapping is favored over recombination of electrons, the concentration of free electrons approaches a limiting value proportional to the intensity of gamma -irradiation. The current in quartz approaches a higher limiting value at Y/sub 1/ = 0.4 r/sec than it does at Y2 = 0.7 r/sec. A maximum in the current as a function of time is observed, when recombination is favored over trapping of electrons. This behavior is observed in the gamma -irradiation of sulfur at 0.3 r/sec at a temperature of 18 deg C. (TTT)
- Research Organization:
- Manchester Coll. of Science and Tech., Eng.
- NSA Number:
- NSA-15-031269
- OSTI ID:
- 4837333
- Journal Information:
- Brit. J. Appl. Phys., Vol. Vol: 12; Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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