We used commercial off-the-shelf (COTS) silicon carbide (SiC) ultraviolet photodiodes for measuring gamma dose rates at high temperature. We tested them with Co-60 gamma dose rates between 0.03 mGy(Air)/s and 3 Gy(Air)/s. The diodes show excellent sensitivity, high signal-to-noise ratio (SNR), and good linearity. They were operated at temperatures up to 200 degrees C with negligible changes of the dark and the radiation-induced current. Gamma irradiation up to a total dose of 1080 kGy(Air), 32-MeV proton irradiations up to a fluence of 8.5 x 10/sup 12/ cm/sup -2/, and 14-MeV neutron irradiations up to 4.1 x 10/sup 12/ cm/sup -2/ demonstrate their radiation hardness. These results and the ability to measure the proton as well as the neutron dose rate after a calibration with Co-60 gammas show that COTS SiC diodes can be used as radiation detectors in harsh environments

The indirect transformation method (program ITP) developed by Glatter since 1977 is still one of the most popular methods for obtaining real-space information from small-angle scattering data. In order to validate the novel structure interference method (SIM), a comparison of the two methods has been performed with both simulated and experimental data. Although no explicit smoothing criterion is used in SIM, the solutions are less influenced by oscillations, termination effects are smaller and higher real-space resolution is obtained compared with ITP. It has been found that the structure interference method is very robust even in the case of incomplete data (h iRma x > re) where the indirect transformation method fails to find a physically meaningful solution.

A variety of commercially available LEDs, LDs, PDs, and optocouplers from two German manufacturers were irradiated at a flash X-ray source, a 6oCo gamma ray source, and a 14 MeV neutron generator. Light output and emission spectrum of the LEDs and LDs were measured before and after irradiation at the 6oCo source. With the PDs we measured the dark current and the photo current before and after 6oCo irradiation. Determination of the sensitivity against neutrons was made off-line. With PDs we measured the photo current induced by pulsed X-rays. The GaAs LED showed a maximum decrease of output power of 28 dB after a total gamma dose of lo6 Gy and LDs a threshold current shift of 80% after neutron fluences of 4 * 1014 cm-2 (1 MeV).

We used commercial off-the-shelf (COTS) silicon carbide (SiC) ultraviolet photodiodes for measuring gamma dose rates at high temperature. We tested them with Co-60 gamma dose rates between 0.03 mGy(Air)/s and 3 Gy(Air)/s. The diodes show excellent sensitivity, high signal-to-noise ratio (SNR), and good linearity. They were operated at temperatures up to 200 degrees C with negligible changes of the dark and the radiation-induced current. Gamma irradiation up to a total dose of 1080 kGy(Air), 32-MeV proton irradiations up to a fluence of 8.5 x 10/sup 12/ cm/sup -2/, and 14-MeV neutron irradiations up to 4.1 x 10/sup 12/ cm/sup -2/ demonstrate their radiation hardness. These results and the ability to measure the proton as well as the neutron dose rate after a calibration with Co-60 gammas show that COTS SiC diodes can be used as radiation detectors in harsh environments

Active optoelectronic devices such as light emitting diodes (LEDs), laser diodes (LDs), photodiodes (PDs), and optocouplers (OCs) were evaluated for degradation under gamma, 14 MeV neutron, and flash X-ray irradiation. Dose rates, total dose values, and neutron fluences were chosen such that we get estimates of the behaviour especially in space environments and nuclear engineering. The devices are designed for wavelengths from 660 to 1550 nm. LEDs showed a decrease of output power between 0.1 and 28 dB after a total gamma dose of 106 0y or neutron fluences of 4x1014 cm2 (1 MeV), respectively. The threshold current of LDs shifted to higher values with increasing dose (60Co) and neutron fluence. Irradiations of PDs with °Co gammas up to a total dose of 106 Gy as well as irradiations with neutrons up to fluences of 4x1014 cm2 (1 MeV) lead to a strong increase of dark current. OCs show a significant reduction of the current transfer ratio (CTR) at dose values between iO and iO Gy. Except two types, the optocouplers did not survive neutron fluences 8x101' cm2 (1 MeV).