Backscattering of Gamma Rays from Tin Slabs

The backscattering of gamma rays from tin slabs was investigated as a function of slab thickness. The point isotropic ⁶⁰Co and ¹³⁷Cs sources were placed on the front face of the scatterer. The obtained data was converted to the response-corrected spectra with the aid of an inverse response matrix, and the angular and energy distributions of backscattered photons were obtained and compared with the other experimental and calculated results

Response Function of a 1-inch Diameter by 6-inch Long ³He Proportional Counter to Neutrons

The response of a 1-inch diameter by 6-inch long ³He proportional counter, of which the gas filling is 4 atm ³He and 2 atm krypton, to axially incident neutrons has been studied and expressed as a 50 by 50 matrix for an energy range from zero to 5 MeV. Applications of the matrix were examined for the purpose of obtaining response-corrected spectra of neutrons transmitted through a matter

Spacial Distribution of Photoneutrons in an Iron Slab Produced by 20-MeV Electron Bombardment

Photoneutron distribution was measured with activation of aluminum and magnesium in an iron slab bombarded by a beam of 20-MeV electrons from a linear accelerator. In order to compare with the experimental results, the spacial neutron distribution was calculated as follows : the photoneutron source distribution originating from the photonuclear reaction was calculated by an approximate analytical method ; and the neutron distribution in the medium was calculated on the basis of this distributed source by Monte Carlo code, CYGNUS. The calculated neutron distribution was in good agreement with the measured distribution, using activities of aluminum detectors. From the comparison of both saturated activities of aluminum and magnesium, it is found that the photonuclear effects are remarkable when γ is equal to 10 cm and Z is between 2 and 5 cm. The spacial distribution of neutron flux above about 6.5 MeV in the iron slab is nearly spherical symmetric around the beam incident point ; and an exponential attenuation with the slope of effective removal cross section of iron, ∑ₑffᴿ＝0.172 cm⁻¹

Development of a low-alpha-emitting {\mu}-PIC for NEWAGE direction-sensitive dark-matter search

NEWAGE is a direction-sensitive dark-matter-search experiment that uses a micro-patterned gaseous detector, or {\mu}-PIC, as the readout. The main background sources are {\alpha}-rays from radioactive contaminants in the {\mu}-PIC. We have therefore developed a low-alpha-emitting {\mu}-PICs and measured its performances. We measured the surface {\alpha}-ray emission rate of the {\mu}-PIC in the Kamioka mine using a surface {\alpha}-ray counter based on a micro TPC.Comment: 6 pages, 4 figure

Spin-spiral structures in free-standing Fe(110) monolayers

科研費報告書収録論文(課題番号:16310081/研究代表者:白井正文/ナノ磁性材料におけるスピン構造とそのダイナミクスに関する理論研究

Increase of Pro-opiomelanocortin mRNA Prior to Tyrosinase, Tyrosinase-Related Protein 1, Dopachrome Tautomerase, Pmel-17/gp100, and P-Protein mRNA in Human Skin After Ultraviolet B Irradiation

In ultraviolet-induced tanning, the protein levels of various gene products critical for pigmentation (including tyrosinase and tyrosinase-related protein-1) are increased in response to ultraviolet B irradiation, but changes in mRNA levels of these factors have not been investigated in vivo. We have established an in situ hybridization technique to investigate mRNA levels of pro-opiomelanocortin, tyrosinase, tyrosinase-related protein-1, dopachrome tautomerase, P-protein, Pmel-17/gp100, and microphthalmia-associated transcription factor, and have analyzed the changes in mRNA levels in the ultraviolet B-exposed skin in vivo. The right or left forearm of each volunteer was irradiated with ultraviolet B, and skin biopsies were obtained at 2 and 5 d postirradiation. mRNA level of pro- opiomelanocortin was increased 2 d after ultraviolet B irradiation, and returned to a near-basal level after 5 d, whereas the mRNA levels of tyrosinase, tyrosinase-related protein-1, dopachrome tautomerase, P-protein, and Pmel-17/gp100 showed some or no increase at 2 d, but were significantly increased 5 d after ultraviolet B irradiation. Microphthalmia-associated transcription factor mRNA was slightly increased on days 2 and 5 after ultraviolet B irradiation. Our results suggest that the mechanism of the tanning response of human skin may involve the transcriptional regulation of certain pigmentary genes, and that pro-opiomelanocortin-derived melanocortins such as α-melanocyte-stimulating hormone and adrenocorticotropic hormone may play a part in regulating these genes in vivo