Narrow bandwidth Si/C multilayer mirrors are fabricated and characterized for the Z-pinch plasma diagnostic at a wavelength of 16.5 nm. To reduce the large stress of the multilayer and maintain a practical reflectivity, different working pressures, from 0.13 Pa to 0.52 Pa, are optimized during the deposition. The grazing incidence x-ray reflectometry (GIXR) measurement and the fitting results indicate that an interlayer was formed at the interfaces, while both the interlayer thickness and interface widths increase with larger working pressure. The surface roughness of the multilayers also increases from 0.13 nm at 0.13 Pa to 0.29 nm at 0.52 Pa, as revealed by the atomic force microscope (AFM) measurements. The multilayer stress decreases from -682 MPa to -384 MPa as the working pressure increases from 0.13 Pa to 0.52 Pa, respectively. The experimental extreme ultraviolet (EUV) reflectivity of the samples with 20 bilayers gradually decreased from 26.3% to 18.9% with increased working pressure. The bandwidth of the reflection peak remains similar for the different samples with a full width half-maximum (FWHM) value of around 0.87 nm. A maximum EUV reflectivity of 33.2% and a bandwidth of 0.64 nm were achieved by the sample with 50 bilayers fabricated under a working pressure of 0.13 Pa.
In this work, a betavoltaic combined with photovoltaic mechanism using strontium-90 as a radioactive source was built up. A transparent yttrium aluminum garnet ceramic doped with a cerium ion is used as an intermediate conversion layer to avoid direct irradiation to a semiconductor conversion device and translates most of the high energy beta particles into photons. The traditional crystalline silicon conversion device with an N+PP+ junction structure functions as a betavoltaic and photovoltaic conversion device simultaneously. Radiation resistance is demonstrated by a 0.9 MeV electron beam irradiation aging experiment. In the optimized betavoltaic setup with a 0.5 mm transparent yttrium aluminum garnet ceramic, the crystalline silicon conversion device can bear 5 × 1015 e/cm2 by degrading output power less than 15%. Loaded with 1.3 mCi strontium-90, this betavoltaic setup produces a short circuit current of 282 nA, an open circuit voltage of 0.168 V, a fill factor of 0.58, and a total conversion efficiency of 0.32%.
The magnetic proton recoil (MPR) spectrometer is a novel diagnostic instrument with high performance for measurements of neutron spectra in inertial confinement fusion (ICF) experiments and high power fusion devices. A compact MPR-type spectrometer dedicated to the research of pulsed deuterium-tritium (DT) neutron spectroscopy of special experimental conditions is currently under design. Analyses of the main parameters and performance of the magnetic analysis system through 3-D particle transport calculations and MonteCarlo simulations and calibration of the system performance as a test using CR-39 solid track detector and α particle from 239Pu and 226Ra radioactive sources are presented in this paper. The results indicate that the magnetic analysis system will achieve a detection efficiency level of 10−5 −10−4 at an energy resolution of 1.5%–2.1%, and fulfills the design goals of the spectrometer.
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