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We propose a new structure of a TES and a series connection of radiation absorber, which can stabilize the absorber temperature through a negative feedback process in the absorber. We consider that this structure of the self-heating absorber might allow TES to improve detection efficiency with large effective area and high count rate by the cooling power inside the absorber. The 150 μm × 150 μm gold film absorber and the 25 μm × 25 μm heat sensor made by Iridium/Gold bi-layer superconductor which has a Tc of 110 mK are biased in series. In this device the gold film absorber generates the self Joule heating to a certain extent to maintain the temperature of the TES pixel. By the photon incidence to the gold film absorber, thermalization of the heat sensor induces the large current reduction, then the current through the gold film absorber also reduces, therefore the gold film absorber is expected to be cooled rapidly by the reduction of joule heating power. This TES pixel achieves the energy resolution of 34 eV (FWHM) @ 5.9 keV and the time decay constant of 150 μs. Furthermore, we tried to perform the experiment of X-ray fluorescence analysis in the SPring-8 synchrotron facility. This TES pixel succeeded to resolve into the energy peaks derived from the material elements which contained in a stainless steel sample. [ABSTRACT FROM AUTHOR]

Precise measurement of neutron beta decay tests predictions of the Standard Model of electroweak interaction. The co-efficient a of the antineutrino/electron angular correlation is determined by measuring the energy spectrum of the recoil protons generated in the neutron beta decay. A proton spectrometer required for this measurement demands high detection efficiency, high energy resolution and a large detection area. We have begun development of a Transition Edge Sensor (TES) microcalorimeter for use as a low energy particle detector. To realize the large detection area we have designed a pixelated TES array incorporating a parallel biasing scheme. Our TES device consists of 4-pixels using a Au/Ti/Au trilayer film adjusted to a superconducting transition temperature of Tc ∼ 380 mK. This temperature is convenient for use in a 3He cryostat with a pulse tube refrigerator. The Au films improve thermal conductivity, thereby reducing position dependent effects and allow an increased detector area. [ABSTRACT FROM AUTHOR]