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Here, we demonstrate an accurate terahertz (THz) power calibration toward tens of nanowatt levels at room temperature. A power reference standard based on a calorimeter with extremely low noise is realized by introducing vacuum insulation panels utilized for thermal insulation. The standard provides a measurement capability of 26.7 nW with the expanded uncertainty of 4.2% (k = 2) at 1 THz. The direct‐comparison calibration of a commercially available power meter is performed by considering its detectable power levels using the standard. A thermopile‐type power meter is used as the device under test, and its calibration factors are determined at 1 and 1.5 THz over a power‐level range of 0.66–1.56 µW. We evaluate the measurement uncertainties of the calibration and find a relative expanded uncertainty of 4.8–9.0% (k = 2). © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

A primary standard for the absorbed dose rate to water in a 60Co radiation field has been newly established at the National Metrology Institute of Japan. This primary standard combines the calorimetric measurements using a graphite calorimeter with the ionometric measurements using a thick-walled graphite cavity ionisation chamber. The calorimeter is operated in the constant temperature mode using AC Wheatstone bridges. The absorbed dose rate to water was determined to be 12 mGy s−1 at a point of 1 m from the radiation source and at a water depth of 5 g cm−2. The uncertainty on the calibration coefficient in terms of the absorbed dose to water of an ionisation chamber using this standard was estimated to be 0.39 % (k=1). [ABSTRACT FROM PUBLISHER]

The differential and total cross sections were measured for the γp → ηp and γd → ηpn reactions at Eγ ≤ 1150 MeV by using an electro-magnetic (EM) calorimeter SCISSORS II at the Laboratory of Nuclear Science (LNS), Tohoku University. The total cross section on the deuteron shows a bump around Eγ = 1 GeV, while no bump is observed in the same energy region of that on the proton. This bump is attributed to be a nucleon resonance excited from the neutron, and it is a candidate of anti-decuplet penta-quark baryons with hidden strangeness. It was difficult, however, to detect all the γ's coming from η decay since the solid angle of SCISSORS II was only 12.6% in total. Statistics of the detected η produced events is poor and systematic uncertainty of the obtained cross section is not small due to low acceptance. A new EM calorimeter complex called FOREST with a solid angle of about 4π sr has been constructed. The spin and parity of the relevant resonance are expected to be determined by the experiments with FOREST. [ABSTRACT FROM AUTHOR]

For fine segmented scintillator calorimeter, we need semiconductor-based photon sensor. Progress for MPPC which is developed in Japan is presented. One of the results which is relevant to photon detection efficiency indicates promising future of MPPC. However, further development is required for the dynamic range and operating voltage value. [ABSTRACT FROM AUTHOR]

We are developing a Ti/Au TES microcalorimeter array for future Japanese X-ray astronomy missions. The goal is an energy resolution of 2–5 eV at 6 keV, and an array of 100–1000 pixels to achieve a geometrical area of >1 cm2 and a moderate spatial resolution simultaneously. The energy resolution was improved to ∼6 eV at 6 keV with a very fast time constant (<100 μs). To achieve a high coverage fraction, it is necessary to fabricate mushroom-shaped X-ray microabsorbers. We are developing an electrodeposition fabrication technique that is suitable for our process. Sn was used as absorber material, but the energy resolution was not good due to the existence of long-lived quasiparticles. Bi is also used, and the process is under optimization now. The readout strategy is to multiplex signals in the frequency domain, using a bridge circuit. So far, we succeeded in multiplexing two pixels modulated with 50 and 20 kHz at 440 mK. The energy resolution obtained at 110 mK was 33 eV (25 kHz). [Copyright &y& Elsevier]

We are developing transition edge sensor (TES) microcalorimeter arrays for future Japanese astronomy missions. Although 6.6 eV energy resolution for 5.9 keV and 74 μs decay time are achieved, our energy resolution was limited by the excess noise of unknown origin. The dominant noise showed 1/R dependence and it only appeared when the current through the TES, I, is larger than 10 μA. This is explained if we assume a constant voltage noise source with a level of ∼2(4kTCRn)1/2. We also investigated the influence of I on the TES performance and found the TES sensitivity α is reduced when the ratio of current to the critical current I/IC is large. It can explain the reduction of α observed when operated without a magnetic shield. We also found a strong correlation between IC and α or the baseline width. Thus, we conclude that IC is an essential parameter for the TES performance. [Copyright &y& Elsevier]

Summary: 1. Resting energy expenditure (REE) provides appropriate basic data for the calculation of energy requirements. 2. The REE of 6498 subjects according to sex and age (1 year stratification), with a minimum of 10 subjects per group, was measured systematically using the easy portable calorimeter (Metavine; Vine, Tokyo, Japan). 3. The REE or the REE/kg according to age and sex was observed to obtain the amount of standard deviation (20–25%). 4. The REE/kg for male and female subjects was maintained at a steady level after the age of 15 years and was estimated to be around 29 kcal/kg. [ABSTRACT FROM AUTHOR]