We present the design parameters, production process, and in-flight performance of the X-ray telescope (XRT) onboard Suzaku. The imaging capability is significantly improved over the ASCA XRT, which had half-power diameters of ${3\rlap {.}{}^{\mathrm {\prime }}6}$, to ${1\rlap {.}{}^{\mathrm {\prime }}8}$–${2\rlap {.}{}^{\mathrm {\prime }}3}$ for all four XRT-I modules. The optical axes are found to be distributed within a radius of ${1\rlap {.}{}^{\mathrm {\prime }}3}$, which makes the observation efficiency of all the XRTs more than 97% at the XIS-default observing position. The vignetting over the XIS field of view predicted via ray-tracing coincides with that measured for observations of the Crab Nebula to within $\sim 10\%$. Contemporaneous fits of a power law to all of the XIS spectra of the Crab Nebula taken at the two standard observing positions (XIS/HXD-default positions) gives a flux consistent with that obtained by Toor and Seward (1974, AJ, 79, 995) to within $\sim 2\%$. The pre-collimator on the top of each XRT module successfully reduces the intensity of the stray light from the $20'$ and $50'$-off directions down to the level of pre-flight expectations.

Background Public perceptions and personal characteristics are heterogeneous between countries and subgroups, which may have different impacts on health-protective behaviors during the coronavirus disease 2019 (COVID-19) pandemic. To assess whether self-reported perceptions of COVID-19 and personal characteristics are associated with protective behaviors among general adults and to compare patterns in six different countries. Methods This cross-sectional study uses the secondary data collected through an online survey between 15 and 23 April 2020 across six countries (China, Italy, Japan, Korea, the UK, and the USA). A total of 5945 adults aged 18 years or older were eligible for our analysis. A logistic regression model was used to estimate odds ratios (OR) and 95% confidence intervals (95%CI) of three recommended behaviors (wearing a mask, handwashing, and avoiding social gatherings). Results In most countries except for China, the participants who perceived wearing a mask as being extremely effective to curtail the pandemic were more likely to wear a mask (OR, 95%CI: Italy: 4.14, 2.08–8.02; Japan: 3.59, 1.75–7.30; Korea: 7.89, 1.91–31.63: UK: 9.23, 5.14–17.31; USA: 4.81, 2.61–8.92). Those who perceived that handwashing was extremely effective had higher ORs of this preventive behavior (OR, 95%CI: Italy: 16.39, 3.56–70.18; Japan: 12.24, 4.03–37.35; Korea: 12.41, 2.02–76.39; UK: 18.04, 2.60–152.78; USA: 10.56, 2.21–44.32). The participants who perceived avoiding social gathering as being extremely effective to curtail the pandemic were more likely to take this type of preventive behavior (OR, 95%CI: China: 3.79, 1.28–10.23; Korea: 6.18, 1.77–20.60; UK: 4.45, 1.63–11.63; USA: 4.34, 1.84–9.95). The associations between personal characteristics, living environment, psychological status, and preventive behaviors varied across different countries. Individuals who changed their behavior because of recommendations from doctors/public health officials were more likely to take preventive behaviors in many countries. Conclusions These findings suggest that higher perceived effectiveness may be a common factor to encourage preventive behaviors in response to the COVID-19 pandemic. These results may provide a better understanding of the homogeneity and heterogeneity of factors related to preventive behaviors and improve public health policies in various countries and groups.

Line emissions from helium (He) plasmas have been used for measurement of electron density and temperature in various situations. We performed measurements of He line intensities in recombining plasmas in a divertor simulator, followed by discussion of some potential difficulties of using the line intensity ratio (LIR) method in a divertor environment under detached conditions. When using four line emissions (501.6, 667.8, 706.5, and 728.1 nm), the discrepancy of the results compared to results from the laser Thomson scattering (LTS) method increased along with increasing gas pressure. However, the LIR method agreed well with LTS when a recombination sensitive line emission (447.1 nm) was added. The influence of the transport of metastable atoms is also discussed. Additionally, anomalous characteristics of the LIR method were revealed in hydrogen helium mixture plasmas when the temperature was in the range of 1–4 eV. These anomalies were likely attributable to the dissociative recombination of HeH+.

Se and135 Cs are long-lived fission products and are found in high-level radioactive waste (HLW). The estimation of their inventories in HLW is essential for the safety assessment of geological disposal, owing to their mobility in the strata. In this study, the amounts of 79 Se and 135 Cs in a spent nuclear fuel solution were measured. About 5 g of irradiated UO 2 fuel discharged from a commercial Japanese pressurized water reactor (PWR) with a burn-up of 44.9 GWd/t was sampled and dissolved with 50 mL of 4 M nitric acid in a hot cell for 2 h. After Se and Cs were chemically separated, the amounts of 79 Se and 135 Cs in the spent nuclear fuel solution were measured by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). The amounts of 79 Se and 135 Cs were 5:2 AE 1:5 and 447 AE 40 g/MTU, respectively. The results presented in this study, which are the first postirradiation experimental data in Japan, showed good agreement with those obtained by the ORIGEN2 code using the data library of JENDL-3.3.

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