摘要 :
The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1 ℃ was measured to be 0.64 ± 0.02 (stat.) ±0.06 (sys.) of that at -100℃ Using the reported lig...
展开
The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1 ℃ was measured to be 0.64 ± 0.02 (stat.) ±0.06 (sys.) of that at -100℃ Using the reported light yield at -100℃(46 photons/keV), the measured light yield at 1 ℃ corresponds to 29 photons/keV. This result shows that liquid xenon scintillator provides high light yield even at room temperature.
收起
摘要 :
A strong anticorrelation between ionization and scintillation signals produced by MeV y rays in liquid xenon has been measured and used to improve the energy resolution by combining the two signals. The improvement is explained by...
展开
A strong anticorrelation between ionization and scintillation signals produced by MeV y rays in liquid xenon has been measured and used to improve the energy resolution by combining the two signals. The improvement is explained by reduced electron-ion recombination fluctuations of the combined signal compared to fluctuations of the individual signals. Simultaneous measurements of ionization and scintillation signals were carried out with ~(137)Cs, ~(22)Na, and ~(60)Co γ rays, as a function of electric field in the liquid. A resolution of 1.7% (σ) at 662 keV was measured at 1 kV/cm, significantly better than the resolution from either scintillation or ionization alone. A detailed analysis indicates that further improvement to less than 1 % (σ) is possible with higher light collection efficiency and lower electronic noise.
收起
摘要 :
We have studied the lower critical fields H_(c1) of superconducting iron oxipnictide PrFeAsO_(1-y) single crystals for H parallel and perpendicular to the ah planes. Measurements of the local magnetic induction at positions stradd...
展开
We have studied the lower critical fields H_(c1) of superconducting iron oxipnictide PrFeAsO_(1-y) single crystals for H parallel and perpendicular to the ah planes. Measurements of the local magnetic induction at positions straddling the sample edge by using a miniature Hall-sensor array clearly resolve the first flux penetration from the Meissner state. The temperature dependence of H_(c1) for H‖c is well scaled by the in-plane penetration depth without showing any unusual behavior, in contrast to previous reports. The anisotropy of penetration lengths at low temperatures is estimated to be approx=2.5, which is considerably smaller than the anisotropy of the coherence lengths. This is indicative of multiband superconductivity in this system in which the active band for superconductivity is more anisotropic. We also point out that the local induction measured at a position near the center of the crystal, which has been used in a number of reports for the determination of H_(c1) might seriously overestimate the obtained H_(c1) value.
收起
摘要 :
Cu films were deposited on Si(100) substrates by applying a negative substrate bias voltage using non-mass separated ion beam deposition (IBD) method. By the SIMS results with Cs~+ ion beam, the Cu film deposited at V_s = 0 V was ...
展开
Cu films were deposited on Si(100) substrates by applying a negative substrate bias voltage using non-mass separated ion beam deposition (IBD) method. By the SIMS results with Cs~+ ion beam, the Cu film deposited at V_s = 0 V was found to contain more impurities than the Cu film deposited at V_s = -50 V. On the other hand, from the SIMS results with O_2~+ ion beam, it was found that elements which are easy to be positive ions such as B, Mg, Na, Al, K, Ca and Fe seem to be increased slightly as compared to the those of the Cu film deposited at V_s = 0 V. As a result, higher-purity Cu film deposited at V_s = -50 V could be obtained in comparison with the film deposited at V_s = 0 V. The purification effect of the Cu film deposited at V_s = -50 V was described in details.
收起
摘要 :
Ultrafast photoinduced transitions among three phases-charge density wave (CDW), Mott-Hubbard insulator, and metal-were investigated in an iodine (I)-bridged platinum (Pt) compound by femtosecond reflection spectroscopy. For a wea...
展开
Ultrafast photoinduced transitions among three phases-charge density wave (CDW), Mott-Hubbard insulator, and metal-were investigated in an iodine (I)-bridged platinum (Pt) compound by femtosecond reflection spectroscopy. For a weak photoexcitation, CDW phase over 70 Pt sites is converted to Mott-Hubbard phase by one photon. Such large conversion efficiency makes possible the complete and transient transition from CDW to Mott-Hubbard phase. For a strong excitation, the low-energy spectral weight is increased, suggesting a conversion to a metallic state.
收起
摘要 :
The development of a liquid-xenon photon detector is in progress for an experiment searching for μ~+ → e~+γ at Paul Scherrer Institut (PSI). The detector utilizes liquid xenon as a scintillation material. The scintillation ligh...
展开
The development of a liquid-xenon photon detector is in progress for an experiment searching for μ~+ → e~+γ at Paul Scherrer Institut (PSI). The detector utilizes liquid xenon as a scintillation material. The scintillation light is observed by photomultiplier tubes (PMTs) immersed in a liquid. An energy resolution of 0.76% is reasonably expected for 52.8 MeVγ rays from results obtained with a first prototype, where the active volume of 2.3 1 is viewed by 32 PMTs. Another prototype has been constructed with an active volume of 80 1 and 228 PMTs. The performance of the detector will be tested using laser-induced compton backscattered γ rays up to 40 MeV.
收起
摘要 :
Cu films were deposited on Si (100) substrates at room temperature by a non-mass separated ion beam deposition method. The effect of the negative substrate bias voltage on the property of the Cu films was investigated by using fie...
展开
Cu films were deposited on Si (100) substrates at room temperature by a non-mass separated ion beam deposition method. The effect of the negative substrate bias voltage on the property of the Cu films was investigated by using field emission scanning electron microscopy and secondary ion mass spectroscopy. The Cu film deposited at the negative bias voltage of -50 V showed an extremely fine and homogeneous morphology without a columnar structure. The purity of the Cu film deposited at the bias voltage of -50 V was much improved in comparison with the 6N Cu target, while the Cu film deposited without applying substrate bias voltage contained more impurities than the 6N Cu target.
收起
摘要 :
A novel gamma-ray detector based on a liquid xenon scintillator is under development for a new experiment to search for the lepton flavor violating process μ~+ → e~+γ at the Paul Scherrer Institute (PSI). The experiment is desi...
展开
A novel gamma-ray detector based on a liquid xenon scintillator is under development for a new experiment to search for the lepton flavor violating process μ~+ → e~+γ at the Paul Scherrer Institute (PSI). The experiment is designed to have a sensitivity down to 10~(-14) branching ratio. We constructed a prototype detector with an active volume of 691 to demonstrate the performance of the proposed detector for high-energy gamma rays of around 50 MeV. After a test of the cryogenic system for the prototype detector, we have begun studies with the prototype using a gamma-beam up to 40 MeV from the laser Compton backscattering facility at the TERAS electron storage ring of the National Institute of Advanced Industrial Science and Technology (AIST).
收起
