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Objectives The aim of this AFIRE (Atrial Fibrillation and Ischemic Events With Rivaroxaban in Patients With Stable Coronary Artery Disease) trial subgroup analysis was to examine rivaroxaban monotherapy benefits and their relation to the time between stenting and enrollment among patients after coronary stenting. Background Of 2,215 patients with atrial fibrillation and stable coronary artery disease in the AFIRE trial, rivaroxaban monotherapy was noninferior to rivaroxaban plus antiplatelet therapy (combination therapy) in terms of efficacy and superior for safety endpoints. However, thrombotic risk after antiplatelet therapy cessation remained a concern among 1,444 patients who had undergone coronary stenting >1 year before enrollment. Methods The benefits of rivaroxaban monotherapy in coronary stenting subgroups were assessed for efficacy (a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularization, or death of any cause), safety (major bleeding defined according to International Society on Thrombosis and Haemostasis criteria), ischemic endpoints, net adverse clinical event, and time between stenting and enrollment. Results Efficacy and safety endpoints for monotherapy were superior to combination therapy, with HRs of 0.70 for efficacy (95% CI: 0.50-0.98; P = 0.036) and 0.55 for safety (95% CI: 0.33-0.92; P = 0.019). For ischemic endpoints, the HR was 0.82 (95% CI: 0.58-1.15; P = 0.240). The HR became smaller with longer time between stenting and enrollment (efficacy, P for interaction = 0.158; safety, P = 0.097). Conclusions In patients with atrial fibrillation after coronary stenting, the benefits of rivaroxaban monotherapy for efficacy and safety endpoints were consistent with those in the whole AFIRE trial population. The benefits became apparent with longer time between stenting and enrollment. (Atrial Fibrillation and Ischemic Events With Rivaroxaban in Patients With Stable Coronary Artery Disease Study [AFIRE]; UMIN000016612 , NCT02642419 )

A search for the decay μ + → e + γ , performed at PSI and based on data from the initial three months of operation of the MEG experiment, yields an upper limit on the branching ratio of BR ( μ + → e + γ ) ⩽ 2.8 × 10 − 11 (90% C.L.). This corresponds to the measurement of positrons and photons from ∼ 10 14 stopped μ + -decays by means of a superconducting positron spectrometer and a 900 litre liquid xenon photon detector.

The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1 deg. was measured to be 0.64 +/- 0.02 (stat.) +/- 0.06 (sys.) of that at -100 deg. Using the reported light yield at -100 deg. (46 photons/keV), the measured light yield at 1 deg. corresponds to 29 photons/keV. This result shows that liquid xenon scintillator gives high light yield even at room temperature., Comment: 16pages,12figures

The MEG experiment at PSI searches for the decay μ→eγ at a level of ≈10^−13 on the branching ratio BR(μ→eγ/μ→tot), well beyond the present experimental limit (BR≤1.2×10^−11) and is sensitive to the predictions of SUSY-GUT theories. To reach this goal the experiment uses one of the most intense continuous surface muon beams available (≈10^8μ/s) and relies on advanced technology (LXe calorimetry, a gradient-field superconducting spectrometer as well as flexible and powerful trigger and acquisition systems). In order to maintain the highest possible energy, time and spatial resolutions for such detector, frequent calibration and monitoring, using a Cockcroft–Walton proton accelerator, are required. The proton beam is brought to the centre of MEG by a special bellows insertion system and travels in a direction opposite to the one of the normal μ-beam. Protons interact with a lithium tetraborate (Li2B4O7) nuclear target and produce one γ (17.6 MeV) from the reaction 3-7 Li(p, γ)8-4 or two coincident γs (11.67 and 4.4 MeV) from the reaction 11-5 B(p, γ)12-6 C*. The 17.6 MeV γ is used for calibrating and monitoring the LXe calorimeter (σEγ/Eγ=3.85±0.15% at 17.6 MeV) while the coincident 11.67 and 4.4 MeV γs are used to measure the relative timing of the calorimeter and the spectrometer timing counters (σ_delta_t=0.450±0.015ns).

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay μ→eγ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10^14 muon decays, gives a 90% C.L. upper limit of 2.4×10^-12 on the branching ratio of the μ→eγ decay, constituting the most stringent limit on the existence of this decay to date.

A search for the decay μ+→e+γ, performed at PSI and based on data from the initial three months of operation of the MEG experiment, yields an upper limit on the branching ratio of BR(μ+→e+γ)2.8×10^−11 (90% C.L.). This corresponds to the measurement of positrons and photons from ~10^14 stopped μ+ decays by means of a superconducting positron spectrometer and a 900 litre liquid xenon photon detector.

Space radiation dosimetry measurements have been made on board the Space Shuttle. A newly developed active detector called “Real-time Radiation Monitoring Device (RRMD)” was used (Doke et al., 1995; Hayashi et al., 1995). The RRMD results indicate that low Linear Energy Transfer (LET) particles steadily penetrate around the South Atlantic Anomaly (SAA) without clear enhancement of dose equivalent and some daily periodic enhancements of dose equivalent due to high LET particles are seen at the lower geomagnetic cutoff regions (Doke et al., 1996). We also have been analyzing the space weather during the experiment, and found that the anomalous high-energy particle enhancement was linked to geomagnetic disturbance due to the high speed solar wind from a coronal hole. Additional analysis and other experiments are necessary for clarification of these phenomena. If a penetration of high-energy panicles into the low altitude occurs by common geomagnetic disturbances, the prediction of geomagnetic activity becomes more important in the next Space Station's era.

A previous study suggested that temporary occlusion of a segment of the hepatic vein causes an increase in arterial flow and retrograde portal flow in the occluded segment. Such occlusions might improve the efficacy of arterial infusion therapy. Accordingly, we studied the change in blood flow visible on hepatic arteriograms when a segment of the hepatic vein is temporarily occluded in patients with hepatocellular carcinoma.The study group consisted of 24 patients with nodular-type hepatocellular carcinoma. Conventional hepatic arteriography was followed by hepatic arteriography performed using a balloon catheter to occlude the hepatic vein that was most closely associated with the tumor. Visualization of the tumor-draining veins, portal vein branches, the degree of tumor vascularity, and the density of the hepatogram on the hepatic arteriogram were retrospectively compared before and during venous occlusion. The veins were evaluated visually; an increase of tumor vascularity was defined as an increase in the number of countable tumor vessels during occlusion, and a dense hepatogram was considered to be a definite sinusoidgram induced by venous occlusion.Conventional hepatic arteriography showed the tumor-draining veins to be branches of the portal vein in only two of the 24 patients (8%). Hepatic arteriography during venous occlusion, however, showed the tumor-draining veins to be branches of the portal vein in four of the patients (17%). An increase in the degree of tumor vascularity with venous occlusion was observed only in a patient with an initial arteriohepatic vein shunt. Dense hepatogram and hepatofugal opacification of the portal vein branches in the occluded, tumor-bearing segment were obtained in 10 patients (42%). Eight of these did not have liver cirrhosis, whereas all of the remaining 14 patients did (p.001).Our results suggest that occlusion of a segment of the hepatic vein may be useful during arterial infusion of hepatocellular carcinoma.

A Heavy Ion cosmic ray Telescope (HIT) has been scheduled to be launched into the synchronous orbit in 1993 aiming to observe elemental and isotopic composition of solar energetic particles and galactic cosmic rays. In this paper, we report the results of accelerator beam experiments of a prototype model of HIT. The telescope consists of two dimensional Position Sensitive Detectors (PSDs) and energy loss detectors (PIN type and Li-drifted type). The mass resolution was 1.1 amu in FWHM for 110 MeV/n pure iron ( 56 Fe) beam. By exposing HIT to beams consisting of various nuclides produced by the projectile fragmentation process in a reaction induced by 56 Fe beam, we confirmed that the secondary elements from 16 S to 25 Mn were clearly separated and that also the isotopes were separated for each elements lighter than 22 Ti. The observed mass resolution was 0.57 amu, 0.66 amu and 0.82 amu in FWHM for 18 Ar, 20 Ca and 22 Ti, respectively. We can conclude that the HIT has good prospects of enough ability for o...

A direct search has been made for supermassive relics (heavier than about ${10}^{12}$ GeV/${\mathit{c}}^{2}$) with a 2000-${\mathrm{m}}^{2}$ array of CR-39 track-etch detectors deployed underground for 2.1 yr. The nonobservation of penetrating tracks places a new upper limit for the velocity-dependent flux at 3.2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}16}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ ${\mathrm{sr}}^{\mathrm{\ensuremath{-}}1}$, for magnetic monopoles carrying various magnetic charges, for electrically charged relics, and strange matter. This flux limit corresponds to a limit on the relic abundance of order ${\mathit{n}}_{\mathit{x}}$/${\mathit{n}}_{\ensuremath{\gamma}}$=${10}^{\mathrm{\ensuremath{-}}29}$ relative to the 3-K photons.

The optical properties of LXe in the vacuum ultra violet (VUV), determining the performance of a scintillation calorimeter, are discussed in detail. The available data, measured in a wider spectral region from visible to UV light, and in a large range of Xe densities, from gas to liquid, are examined. It is shown that this information can be used for deriving the LXe optical properties in the VUV. A comparison is made with the few direct measurements in LXe for VUV light resulting from the LXe excitation by ionizing particles. A useful relation is obtained which connects the Rayleigh scattering length to the refractive index in LXe., 20 pages, 12 figures

A liquid-gas double phase xenon detector for WIMPs with a 0.3l active volume has been constructed and tested. Proportional scintillation signals are observed after ionization electrons drifted 8 cm to a multiwire anode mounted in gas phase. Basic properties of the detector and electrons lifetime were measured. The efficiency of background rejection for grays is tested and discussed.

The feasibility of a large-volume liquid xenon Compton telescope based on full event imaging in a time projection chamber has been demonstrated with the development of the balloon-borne instrument LXeGRIT. With its 400 cm2 sensitive area and 7 cm drift gap, the liquid xenon detector images γ-rays in the energy range from 200 keV to 25 MeV. The precise 3-dimensional localization of γ-ray interactions within the sensitive volume provides excellent background reduction capabilities. Together with the large efficiency of a homogeneous detector volume, LXeGRIT addresses the primary instrumental limitations encountered in this energy band. Following engineering tests at balloon altitude in 1997, LXeGRIT has been upgraded with a new trigger and data acquisition system, integrated with the existing readout electronics. Enhanced data transfer capability and onboard data storage were also implemented. LXeGRIT was successfully flown from Ft. Sumner, NM on May 7, 1999. The instrument worked as expected at balloon altitude. The large amount of data gathered during the 9.5 h flight are currently being analyzed. We describe the instrument and present some results from calibration data and preliminary results from the flight.

A scintillating fiber sampling calorimeter telescope (SSCT (SF)) is proposed which is to be operated on board a satellite for the observation of cosmic gamma rays ranging from 200 MeV to 200 GeV. The idea of SSCT (SF) is based on the experience in developing a Si(Li)/Pb sampling calorimeter telescope (SSCT (Si)); SSCT(SF) replaces the Si detectors in SSCT(Si) by scintillating fibers. Some key parameters of SSCT(Si) are: the active area is 2,500 cm2, effective area 1,500 cm2, the median angular reoslution 1.6° at 1 GeV, 0.34° at 10 GeV, 0.21° at 30 GeV, and the r.m.s energy resolution is 20, 17 and 18% at 1, 10 and 100 GeV, respectively. If a thicker calorimeter is used, 17%/√E(GeV) is possible. SSCT(SF) is now under development. From a preliminary test, we expect that the angular resolution of SSCT(SF) is, at worst, almost the same as SSCT(Si), and the energy resolution could be better than 30% at 1 GeV. Probably almost the same energy resolution is obtainable. An effective area of one order of magnitude larger than the EGRET can be attained with a low cost.

Large two-dimensional position-sensitive silicon detectors (PSDs) with good position linearity, resolution and thickness uniformity have been developed. The PSDs have an effective area of 62 mm×62 mm and a thickness of 500 µm. The non-linearity and position resolution for the whole sensitive area are found to be less than 0.26 mm in rms and 0.44 mm in fwhm, respectively, when an energy of 157 MeV is deposited in the detector and a shaping time constant of 12 µs is used in the pulse processing. The non-uniformity of detector thickness is ≤0.1% in rms. The PSDs recently developed are good enough to separate iron isotopes in a telescope aboard the GEOTAIL spacecraft scheduled to be launched at July in 1992.

Measurements of the ionization loss have been achieved with high accuracy using two proportional counters with sensitive lengths of 9 and 30 cm, filled with Ar+10% CH4 mixture at various pressures (0.13 approximately 2.0 atm). The widths of the ionization loss distributions disagree with those predicted by the Landau (1944) and Blunck-Leisegang (1950) theories, but rather, are in fairly good agreement with those calculated by Ispiryan et al. (1974) using the Monte Carlo method. In traversing thin layers of the counter gas, the most probable energy losses are smaller than those predicted by the Landau formula with the inclusion of the Sternheimer correction for the density effect, but the discrepancy decreases as the thickness of the gas layer increases. Furthermore, both sets of data obtained from the two counters lie almost on the curve of the most probable energy loss plotted against the thickness of the counter gas. The Garibyan and Ispiryan interpretation (1972) seems to provide the best explanation as it takes into account the transition radiation effect.

Scintillation counters and gray wedge pulse height analyzer were used to measure gamma -ray spectra from ground surfaces, and It was certified that there was a considerable amount of gamma -ray contributions from fall-out to background radiations in the field. Out-door radiation dosages were measured, distinguishing fall-out radiations from natural background gamma rays (as a dosage to human body at the height of 1 m). Experiments to estimate radiation dosages from natural background gamma rays were also tried. In Kanto loam area, the radiation dosage from natural background gamma rays is small, about one third of the world average. In Kansai district, the dosage is about equivalent or a little larger than the world average radiation dosage. (auth)

A cylindrical gridded ionization chamber with a source area of 5000 cm2, has been constructed as a low background alpha-ray spectrometer. By making use of cathode pulses in the chamber, it is tried to eliminate the background counts caused by alpha-particles emitted from electrodes other than the background surface. The operation condition for reduction of the background counts in this method is shown analytically. Under the condition, very low background of 0.17 counts per hour over spectral line width of 45 keV (fwhm) at 5 MeV is achieved for Mylar sheet backing. Spectra of weak alpha-activities measured by this chamber are also shown.

A proposal is made on the origin of the high energy limit for the Owen-Batchelor method of pulse shape discrimination in a photomultiplier between recoil protons and energetic electrons or muons. According to the proposed mechanism, the initial negative swing of a voltage pulse on the last dynode becomes so large for a high energy electron or a muon, that the space charge effect between the last dynode and the anode would be appreciably reduced as a result of temporary enhancement in the potential difference across the space. This would give rise to a “saturation” of the negative amplitude of the last-dynode voltage pulse against the linear pulse-height, and would result in a rapid increase in the “Owen pulse-height” Vp (the positive amplitude of a last-dynode pulse), as well as in a rapid decrease in the zero-crossover time t0 of the last-dynode pulse, with increasing linear pulse-height. In consequence, the discriminating power would be progressively deteriorated as the linear pulse-height (or the energy deposit Ee in the scintillator) for an electron or a muon exceeds a certain upper limit. Approximate expressions for Vp and t0 are derived as a function of Ee, together with a relation between Vp and t0. Several experimental evidences are presented for the proposed mechanism, including the improving effect of added capacity in the last-dynode circuit as observed recently by Hiramoto et al. It is remarked that the breakdown of discrimination using Vp is necessarily associated with the failure of another method using t0, owing to the presence of a definite relation between Vp and t0.

From the view-point of application to gradient magnets for a strong focusing proton synchrotron, the magnetic and mechanical properties of oriented low carbon steels as well as typical non-oriented low carbon steels are investigated in detail. One gradient magnet of non-oriented steel and two of oriented steel, were constructed and the distributions of field gradient for these magnets were measured at various excitations. As a result of the measurements, it is shown that in the gradient magnet made of oriented steel the use of the field up to 17 kG is possible. Furthermore, the computer calculations of the field gradient distribution for gradient magnets of oriented steel were made by using the magnetic property in the direction perpendicular to the median plane of the magnet gap. The results are in fairly good agreement with those of the field measurements.

An improved method of measuring the alpha-gamma angular correlation is proposed. The apparatus consists of a gridded ionization chamber and a NaI scintillation counter. In a gridded chamber, generally, the cathode pulse yields information on the emission angle of an alpha-particle, while the collector pulse gives information on its energy. Accordingly, the alpha-gamma angular correlation of mixed alpha-sources, in which some isotopes emitting alpha-particles of different energies and subsequent gamma-rays of almost the same energy are included, can be easily measured from the pulse height distribution of the cathode pulses coincident with the scintillation pulses and the collector pulses in the desired energy intervals, respectively. As examples, the angular correlation for two decay series in the daughter products of ThB, which are 1. ThC′ ∗ (γ)ThC′(α)ThD and 2. ThC(α)ThC″ ∗ (4+)(γ) ThC″(5+), were measured. The results are in good agreement with theoretical prediction and those obtained by other workers.

The possibility of improving the high field quality of a strong focusing synchrotron magnet by suitable choice of the pole shape is investigated by computer calculation. It is shown that there is an optimum pole shape on the high field side for a given pole width. With the optimum pole shape the sextupole and octupole components of the field strength can be made appreciably small. Also, by using the results of the calculation, the approximate design of the synchrotron magnet is described.

GEOTAIL spacecraft, a part of ISTP program, is scheduled to be launched in 1992. It includes a package of High Energy Particle instruments (HEP). Two instruments called MI (Medium energy Isotope telescope) and HI (High energy Isotope telescope) among HEP instruments will dedicate to measure elemental and isotropic compositions in SEPs and GCRs. These two instruments have following key features; exceptionally high sensitivity, excellent isotope resolution and wide dynamic ranges of energy and species. These distinguished features can be realized by the Si detector telescopes by the use of newly developed position‐sensitive detectors with a good position response and of very large Si wafers.

The criticisons of Ascarelli1,2 regarding Shibamura et al5’s measurements of electron drift velocity in liquid Ar, Kr and Xe are answered. (AIP)

The scintillation of helium is explained by de-excitation of the excited molecule formed by a three body collision of a metastable atom with ground state atoms.

A stack of CR-39 sheets has been exposed to 96 MeV/n and 2.1 GeV/n Ar beams in order to study uniformity of response and the response curve. Variation in response of the area of about 50 cm × 50 cm for one sheet was within 1.5 %. Roughness of the surface after 27 hr etching and the charge resolution were improved by changing temperature-time curing cycles. Steeper response curve at high REL region was observed and it was confirmed that our CR-39 has higher sensitivity in the recording of nuclear tracks down to Z/β ≃ 6 for vertical incidence.

The fallout rates of radionuclides, /sup 7/Be and /sup 22/Na, in rain water collected at Tokyo were measured monthly during the period from February 1975 to February 1977, using a low-background dual Nal(Tl) coincidence gamma ray spectrometer. It is found that the contribution from nuclear weapon tests to these nuclides is negligibly small. Therefore these activities (/sup 7/Be and /sup 22/Na) are attributed to the cosmic ray produced nuclides in the atmosphere. The average fallout rates of /sup 7/Be and /sup 22/Na measured at ground level of Tokyo are 118 +- 13 and (1.66 +- 0.24) x 10/sup -2/pCi/m/sup 2//d, respectively. These values are in agreement with values estimated by Lal and Peters, within the experimental error. Using the observed fallout rate of /sup 22/Na, the global average fallout rate of /sup 26/Al produced in the atmosphere is estimated to be 5.4 x 10/sup -8/pCi/m/sup 2//d, which is higher by about a factor of ten than the influx rate of cosmic dust bearing /sup 26/Al estimated by Reyss et al. Therefore most of the /sup 26/Al activity contained in the terrestrial sample seems to be originated from the /sup 26/Al produced by cosmic rays in the atmosphere.