Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-03-26
Abstract:Cu precipitates played a key factor in irradiation induced hardening and embrittlement of reactor pressure vessel (RPV).In this work, two kinds of Fe-Cu model alloys with different Cu contents irradiated by Fe ion at 573 K were investigated using positron annihilation techniques and SEM. Doppler Broadening Spectroscopy(DBS) results indicated that with the irradiation dose increased from 0.1 dpa to 1.2 dpa, more vacancy-type defects were induced during Fe ion irradiation, and with different Cu contents, defects condition had few changes. Coincident Doppler Broadening (CDB) results indicated Cu precipitates were formed during the irradiation, which could be verified through the SEM results. The CDB results also showed that the Cu precipitates were the same at 0.1 dpa between the samples with different Cu contents. In Fe0.6Cu samples, more Cu precipitates were formed than that of Fe0.3Cu sample at 1.2 dpa.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-03-24
Abstract:In order to study the fundamental processes of helium retention and thermal desorption from the structural material of future fusion reactors, thermal desorption measurements were performed to investigate helium trapping from defects in binary Fe9Cr model alloys irradiated by 3 keV and 0.2 keV He ions. Interstitial type dislocation loops, vacancies and vacancy clusters were produced by irradiation with 3 keV helium ions, which acted as the sink trapped the helium atoms. Helium thermal desorption peaks from dislocations, helium-vacancies were obtained by thermal desorption spectroscopy at ~ 540 篊, in the range from 205 篊 to 478 篊, respectively. Simple first order dissociation kinetics are used to estimate the activation energies associated with the desorption groups. A sharp desorption peak was observed at ~ 865 篊 due to the BCC-FCC phase transformation for specimens under all examined implantation conditions.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract: Aims. With the next generation of large surveys coming to the stage of observational cosmology soon, it is important to explore their potential synergies and to maximise their scientific outcomes. In this study, we aim to investigate the complementarity of the two upcoming space missions Euclid and the China Space Station Telescope (CSST), focusing on weak lensing (WL) cosmology. In particular, we analyse the photometric redshifts (photo-zs) and the galaxy blending effects. For Euclid, WL measurements suffer from chromatic PSF effects. For this, CSST can provide valuable information for Euclid to obtain more accurate PSF, and to calibrate the color and color-gradient biases for WL measurements. Methods. We create image simulations for different surveys, and quantify the photo-z performance. For blending analyses, we employ high-resolution HST/CANDELS data to mock Euclid, CSST, and an LSST-like survey. We analyse the blending fraction for different cases, and the blending effects on galaxy photometry. Furthermore, we demonstrate that CSST can provide a large enough number of high SNR multi-band galaxy images to calibrate the color-gradient biases for Euclid. Results. The sky coverage of Euclid lies entirely within the CSST footprint. The combination of Euclid with CSST data can be done more uniformly than with the various ground-based data. Our studies show that by combining Euclid and CSST, we can reach a photo-z precision of $\sigma_{\rm NMAD} \approx 0.04$, and an outlier fraction of $\eta\approx 2.4\%$. Because of the similarly high resolutions, the data combination of Euclid and CSST can be relatively straightforward for photometry. To include ground-based data, however, sophisticated deblending utilizing priors from high-resolution space data is demanded. The color-gradient biases for Euclid can be well calibrated to the level of 0.1% using galaxies from CSST deep survey.
Peer Review Status:Awaiting Review