Development of Superconducting Multilayer Wiring for Large Arrays of TES X-Ray Microcalorimeters

We are developing TES (Transition Edge Sensor) X-ray Microcalorimeters for future X-ray astronomy missions such as DIOS (Diffuse Intergalactic Oxygen Surveyor). Standard wiring for a large-format array requires narrow and closely-packed configuration. This can cause deleterious crosstalk especially in the Frequency Domain Multiplexing readout. Hence we have employed multilayer wiring technique. In this paper, we tested a deposition of a TES film on the multilayer wiring by sputtering. Our first trial showed that the TES pixels have large residual resistances >50?mΩ and small critical currents of <1?μA. To improve the coverage of the TES film on the wiring, we increased the thickness of TES film (Ti/Au thickness of 100/200?nm). Also to remove an oxidation layer on the Al wiring, we strengthened a reverse-sputtering (150 W, 3?min) before the sputtering of TES. After these treatments, the TES film showed a sharp transition with small residual resistance (～1?mΩ) and large critical current (>30?μA).     

Crystallinity and electrical conductivity of sulfur-containing microcrystalline diamond thin film

Hydrogen sulfide (H₂S) was introduced into a microwave plasma chemical vapor deposition of microcrystalline diamond thin film. Secondary-ion mass spectroscopy showed that sulfur concentration was controlled from 2 × 10¹⁵ to 9 × 10¹⁷ cm^− 3 by controlling the H₂S/CH₄ ratio, while that of hydrogen concentration was around 5 × 10²⁰ cm^− 3 and was independent of the H₂S/CH₄ ratio. Electrical conductance increased linearly as the S concentration increased from 2 × 10¹⁵ to 3 × 10¹⁶ cm^− 3 without significant deterioration of film crystallinity, i.e., the amount of sp² phase did not increase. Non-ohmic conduction was converted to ohmic conduction when the S concentration reached 9 × 10¹⁷ cm^− 3 by increasing the H₂S/CH₄ ratio to 30,000 ppm. This modification was consistent to the formation of a graphitic phase by heavy S-doping, which was identified by Raman spectra and surface morphology.     

Lifetime test and heritage on orbit of coolers for space use

This report describes the results and operating status of ground lifetime testing and achievements on orbit of coolers for space use. Ground lifetime tests of coolers of three types were conducted to demonstrate their long life and reliability. Three single-stage Stirling coolers were tested for 89,016, 71,871 and 68,273 h from 1998, a two-stage Stirling cooler was tested for 72,906 h, and a 4-K class cooler with a two-stage Stirling cooler and a Joule–Thomson cooler was tested for over 2.5 years. After lifetime tests were completed, a few coolers were investigated to determine the cause of the cooling performance degradation. Additionally, the filled gas of the coolers was analyzed. These coolers have shown good results on orbit. Three single-stage Stirling coolers were carried on the X-ray astronomical satellite “SUZAKU” (launched in July 2005), Japanese lunar polar orbiter “KAGUYA” (launched in September 2007), and the Japanese Venus Climate Orbiter “AKATSUKI” (launched in June 2010). Two units of a two-stage Stirling cooler were carried on the infrared astronomical satellite “AKARI” launched in February 2006. A 4-K class cooler was carried on the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) aboard the Japanese Experiment Module (JEM) of the International Space Station (ISS). SMILES was launched in September 2009.     

Formation of magnesium silicate hydrate and its crystallization to talc

Mixtures of Mg(OH)₂ and colloidal silica with Mg/Si = 0.75 were treated hydrothermally at 180° to 600°C for 4 h ? 8 weeks. Reaction seemed always to proceed through the formation of magnesium silicate hydrate to talc, which had random displacements of layers parallel to b of nb/3, and gave a decrease of the basal spacing with increase of crystallinity. The magnesium silicate hydrate gave X-ray powder patterns indicative of two-dimensional crystals without basal spacing, had a specific area of about 300 m²/g, and gave an exotherm at 830°C. Dehydration and infrared spectra for products are also described.     

Bleeding infectious enteritis

A recent trend on bleeding intestinal infections in Japan was described. Salmonella Enteritidis infection occupied over 42% of food-borne diseases in 1996. Salmonella Enteritidis is the most popular infectious agent for food-borne outbreak in Japan. Salmonella Typhimurium DT104 which is widely spread in Europe and in U.S.A. is not common in Japan. We experienced large outbreak of foodbore EHEC/VTEC O157: H7 infections in 1996. Since then, diagnostic and therapeutic studies on EHEC/VTEC infection and haemolytic uremic syndrome are promoted by the Government. HACCP may take an important roll for the prevention of large outbreaks of foodbore EHEC/VTEC infections.     

Leukemia developing after 131I treatment for thyroid cancer in a patient with Werner's syndrome: molecular and cytogenetic studies

A 40-year-old female patient with Werner's syndrome (WS) suffering from thyroid cancer and myelodysplastic syndrome (MDS) is reported. She had been diagnosed as having WS complicated with thyroid cancer seven years previously. Total thyroidectomy and radioactive iodine (131I, 100 mCi/year) therapy for seven years had slowed the progression of thyroid cancer. She suffered a sudden onset of MDS at the age of 40 years. After six months she died from overt leukemia. We found an additional chromosome aberration of chromosome 10 in the progression of leukemia from MDS.