Search

We have developed the FeCo nanocontact magnetoresistance (NCMR) with spin-valve structure [H. N. Fuke et al., IEEE Trans. Magn. 43, 2848 (2007)] which exhibits up to a MR ratio of 11%–12% at a resistance area (RA) of 0.3–0.55 Ω μm2. The nanocontact configurations were estimated at about 2 nm in in-plane diameter, 1.2 nm in thickness, and 0.55% in density for a RA∼0.5 Ω μm2 film based on in-plane current distribution by conductive atomic-force microscopy cross sectional transmission electron microscope images of the NCMR. The origin of the NCMR was discussed by comparing magnetic field dependence of resistance, with micromagnetics simulation based on the diffusive MR theory. It is found that our NCMR cannot be explained by diffusive domain wall theory or bulk scattering in free and pinned layers. It is likely that a theory on the basis of a ballistic MR consideration is needed to interpret our MR origin. [ABSTRACT FROM AUTHOR]

The balloon-borne experiment with a superconducting spectrometer (BESS) instrument was developed as a high-resolution, high-geometric-acceptance magnetic-rigidity spectrometer for sensitive measurements of cosmic-ray antiparticles, searches for antinuclei, and precise measurements of the absolute fluxes of light GCR elements and isotopes. The original BESS experiment flew 8 times over Lynn Lake, Canada and once from Fort Sumner, USA during the period of 1993 through 2002, with continuous improvement in the instrument. Based on the instrument concept inherited from the BESS spectrometer, a very low instrumental energy cutoff for antiprotons was achieved with a new thin-walled superconducting magnet and removal of the outer pressure vessel for BESS-Polar project. The first and second scientific flights called BESS-Polar I/II were successfully performed, over Antarctica in 2004 December and 2007 December respectively. We report the scientific results, focusing on the long-duration flights of BESS-Polar I (2004) and BESS-Polar II (2007–2008). [ABSTRACT FROM AUTHOR]

Abstract: The General Anti-Particle Spectrometer (GAPS) project is being carried out to search for primary cosmic-ray antiparticles especially for antideuterons produced by cold dark matter. GAPS plans to realize the science observation by Antarctic long duration balloon flights in the late 2010s. In preparation for the Antarctic science flights, an engineering balloon flight using a prototype of the GAPS instrument, “pGAPS”, was successfully carried out in June 2012 in Japan to verify the basic performance of each GAPS subsystem. The outline of the pGAPS flight campaign is briefly reported. [Copyright &y& Elsevier]

Abstract: The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) is configured with a solenoidal superconducting magnet and a suite of precision particle detectors, including time-of-flight hodoscopes based on plastic scintillators, a silica-aerogel Cherenkov detector, and a high resolution tracking system with a central jet-type drift chamber. The charges of incident particles are determined from energy losses in the scintillators. Their magnetic rigidities (momentum/charge) are measured by reconstructing each particle trajectory in the magnetic field, and their velocities are obtained by using the time-of-flight system. Together, these measurements can accurately identify helium isotopes among the incoming cosmic-ray helium nuclei up to energies in the GeV per nucleon region. The BESS-Polar I instrument flew for 8.5days over Antarctica from December 13th to December 21st, 2004. Its long-duration flight and large geometric acceptance allow the time variations of isotopic fluxes to be studied for the first time. The time variations of helium isotope fluxes are presented here for rigidities from 1.2 to 2.5GV and results are compared to previously reported proton data and neutron monitor data. [Copyright &y& Elsevier]

In two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium candidate was found in BESS-Polar I data among 8.4 X 106 |Z| = 2 nuclei from 1.0 to 20 GV or in BESS-Polar II data among 4.0 X 107 |Z| = 2 nuclei from 1.0 to 14 GV. Assuming antihelium to have the same spectral shape as helium, a 95% confidence upper limit to the possible abundance of antihelium relative to helium of 6.9 X 10-8 was determined combining all BESS data, including the two BESS-Polar flights. With no assumed antihelium spectrum and a weighted average of the lowest antihelium efficiencies for each flight, an upper limit of 1.0 X 10-7 from 1.6 to 14 GV was determined for the combined BESS-Polar data. Under both antihelium spectral assumptions, these are the lowest limits obtained to date. [ABSTRACT FROM AUTHOR]

The energy spectrum of cosmic-ray antiprotons (¯p's) from 0.17 to 3.5 GeV has been measured using 7886 ¯p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary ¯p calculations. Cosmologically primary ¯p's have been investigated by comparing measured and calculated p spectra. BESS-Polar II data show no evidence of primary ¯p's from the evaporation of primordial black holes. [ABSTRACT FROM AUTHOR]

Abstract: The super-pressure balloon (SPB) has been expected to be a flight vehicle that can provide a long flight duration to science. Since 1997, we have developed the SPB. Now we are at the phase of developing an SPB of a practical size. In 2009, we carried out a test flight of a pumpkin-shaped SPB with a 60,000m3 volume. The undesirable result of this flight aroused us to resolve the deployment instability of the pumpkin-shaped SPB, which has been known as one of the most challenging issues confronting SPB development. To explore this deployment issue, in 2010, we carried out a series of ground tests. From results of these tests, we found that an SPB design modified from pumpkin, named “tawara”, can be a good candidate to greatly improve the deployment stability of the lobed SPB. [Copyright &y& Elsevier]

Abstract: Since 1971, numerous balloons have been launched from the Japanese balloon base, the Sanriku Balloon Center (SBC). Through these years, balloon technologies have been developed continuously and many scientific achievements have resulted. Recently, however, because of the limited area of the launching pad of the SBC, we have been faced with the difficulty of safely launching large balloons. To solve this issue, we decided to move the balloon base from the SBC to the Taiki Aerospace Research Field (TARF) in northern Japan. The TARF had an existing huge hanger and a paved launch pad capable of being utilised for balloon operations. To evolve the TARF into a new balloon base, new balloon facilities have been constructed at the TARF and equipment was transferred from the SBC to the TARF during July 2007 and March 2008. The SBC was closed in September 2007, and the new base became operational in May 2008. The new base at the TARF is designed to launch larger balloons with greater safety and to perform balloon operations more effectively than ever before. In the summer of 2008, we carried out the first series of the balloon campaign at the TARF, and succeeded in two engineering flights of stratospheric balloons. By the success of these flights, we have verified that the whole system of the new balloon base is well established. [Copyright &y& Elsevier]

Abstract: The BESS-Polar spectrometer had its first successful balloon flight over Antarctica in December 2004. During the 8.5-day long-duration flight, almost 0.9 billion events were recorded and 1,520 antiprotons were detected in the energy range 0.1–4.2 GeV. In this Letter, we report the antiproton spectrum obtained, discuss the origin of cosmic-ray antiprotons, and use antiproton data to probe the effect of charge-sign-dependent drift in the solar modulation. [Copyright &y& Elsevier]

Abstract: We discuss current progress and future plans for the general antiparticle spectrometer experiment (GAPS). GAPS detects antideuterons through the X-rays and pions emitted during the deexcitation of exotic atoms formed when the antideuterons are slowed down and stopped in targets. GAPS provides an exceptionally sensitive means to detect cosmic-ray antideuterons. Cosmic-ray antideuterons can provide indirect evidence for the existence of dark matter in such form as neutralinos or Kaluza–Klein particles. We describe results of accelerator testing of GAPS prototypes, tentative design concepts for a flight GAPS detector, and near-term plans for flying a GAPS prototype on a balloon. [Copyright &y& Elsevier]

Abstract: Historically, there are been many searches for fractionally charged particles in the cosmic radiation. However, few searches have been performed near the top of the atmosphere. We performed a search for relativistic charged particles in cosmic rays using data collected during four BESS balloon flights from 1997 to 2000 carried out in northern Canada. The data were analyzed by examining energy deposition in the time-of-flight scintillator hodoscopes. No candidate was found. We derive an upper limit of 4.5×10−7 (cm2 ssr)−1 for the flux of charged particles, at the 90% confidence level. [Copyright &y& Elsevier]

Background Radiofrequency ablation (RFA) therapy for hepatocellular carcinoma has enabled good local control to be possible. However, after successful local control, distant recurrences frequently occur in the remnant liver. Aim To identify the predictive factors for distant recurrence after RFA. Methods A total of 117 patients with initial non-advanced hepatocellular carcinoma with HCV who underwent RFA in our hospital were selected for this study. After transcatheter chemoembolization, RFA was performed under real-time computed tomography-fluoroscopic guidance. We studied survival rates, local (adjacent to treated tumour) and distant (intrahepatic site distant from the treated tumours) recurrence rates, as well as predictive factors for distant recurrence. Results After RFA, survival rates were 98.2% and 64.7% at 1 and 5 years, respectively. Child B patients had a significantly worse survival than Child A. Recurrence rates were 2.4% at 5 years for local, and 17.1% and 76.9% at 1 and 5 years, respectively, for distant. The Kaplan–Meier method revealed significantly high recurrence rates in cases with low albumin levels (Alb < 3.5 g/dL), high aspartate aminotransferase levels (AST > 60 IU/L), high alanine aminotransferase levels (ALT > 60 IU/L), low platelet counts (Plt < 10 × 104/μL), and high alpha-fetoprotein levels (AFP > 50 ng/mL). On multivariate analysis, low Alb levels and high AST levels were independent predictive factors for distant recurrence. Conclusions Although RFA enables good local control for initial hepatocellular carcinoma, distant recurrence is observed at high rates in HCV patients. Low albumin and high AST levels are predictive factors for distant recurrence. [ABSTRACT FROM AUTHOR]

We developed a compact RF receiver front-end subsystem using a high-Tc superconducting sharp-skirt band-pass filter with a center frequency tuning function. The subsystem had two pairs of the tunable filter and an LNA on board. A 23-pole hairpin-type 2-GHz microstrip-line filter was fabricated with YBa2Cu3Oy thin films deposited on a 35-mm-wide and 70-mm-long sapphire substrate. Attenuation characteristics were more than 40 dB at 1 MHz, apart from both the lower and the higher pass-band edges. For center frequency tuning, a 1-mm-thick dielectric sapphire plate was stacked on the filter, and the filtering characteristics were tuned by moving the plate using a piezoelectric bending actuator. The range of the center frequency modulation was more than 10 MHz with no significant degradation of the low-loss and sharp-skirt characteristics. [Copyright &y& Elsevier]

Studies a two-GHz 12-pole superconducting microstrip line filter and a two-pole electrically tunable filter fabricated using interdigital electrodes and dielectric films. Changes in the dielectric constant of the films; Range of the center frequency modulation; Improvements in microwave frequency response.

This study presents a fabrication process for lithium-drifted silicon (Si(Li)) detectors that, compared to previous methods, allows for mass production at a higher yield, while providing a large sensitive area and low leakage currents at relatively high temperatures. This design, developed for the unique requirements of the General Antiparticle Spectrometer (GAPS) experiment, has an overall diameter of 10 cm, with ∼ 9 cm of active area segmented into 8 readout strips, and an overall thickness of 2.5 mm, with ≳ 2. 2 mm (≳ 90 %) sensitive thickness. An energy resolution ≲ 4 keV full-width at half-maximum (FWHM) for 20 − 100 keV X-rays is required at the operating temperature ∼ − 40 ° C , which is far above the liquid nitrogen temperatures conventionally used to achieve fine energy resolution. High-yield production is also required for GAPS, which consists of ≳ 1000 detectors. Our specially-developed Si crystal and custom methods of Li evaporation, diffusion and drifting allow for a thick, large-area and uniform sensitive layer. We find that retaining a thin undrifted layer on the p -side of the detector drastically reduces the leakage current, which is a dominant component of the energy resolution at these temperatures. A guard-ring structure and optimal etching of the detector surface are also confirmed to suppress the leakage current. We report on the mass production of these detectors that is ongoing now, and demonstrate it is capable of delivering a high yield of ∼ 90 %. [ABSTRACT FROM AUTHOR]

Investigates the microstructure effect to improve the critical-current density properties for the YBCO crystal. Clarification of the pinning mechanism; Efficacy of the a- and c-axis grain as pinning centers; Composition of the film surface microstructures.

The article presents a case study of a 32-year-old woman with focal nodular hyperplasia (FNH). Topics discussed include the magnetic resonance imaging (MRI) on FNH, the anti-mitochondrial antibody, and the levels of alpha fetoprotein. Also mentioned are the diagnosis for hepatic tumors, the liver biopsy, and the hepatitis C virus antibody.

The lithium-drifted silicon (Si(Li)) detector developed for the General Antiparticle Spectrometer (GAPS) experiment features a thick (∼ 2.2 mm) sensitive layer, large (10 cm) diameter, and excellent energy resolution (∼ 4 keV for 20–100 keV X-rays) at a relatively high operating temperature (approximately −40 °C). Mass production of GAPS Si(Li) detectors has been performed to construct a large-volume silicon tracker for GAPS. We achieved the first success of the mass production of large-area Si(Li) detectors with a high (∼ 90%) yield rate. Valuable datasets related to detector fabrication, such as detector performance and manufacturing parameters, were recorded and collected during the mass production. This study analyzes the datasets using statistical methods with the aim of comprehensively examining the mass production and to gain valuable insight into the fabrication method. Sufficient uniformities of the performance parameters (leakage current and capacitance) between detectors and strips are found, demonstrating high-quality and stable mass production. We also search for correlations between detector performance and manufacturing parameters by using data-mining techniques. Conventional multivariate analysis (multiple regression analysis) and machine-learning techniques (regression tree analysis) are complementarily used, and it is found that the Li-drift process makes a significant contribution to the performance parameters of the finished detectors. Detailed investigation of the drift process is performed using environmental data, and physical interpretations are presented. Our results provide valuable insight into the fabrication methods for this kind of large-area Si(Li) detector, and encourages future projects that require large-volume silicon trackers. [ABSTRACT FROM AUTHOR]

The CALorimetric Electron Telescope (CALET) on the International Space Station consists of a high-energy cosmic-ray CALorimeter (CAL) and a lower-energy CALET Gamma-ray Burst Monitor (CGBM). CAL is sensitive to electrons up to 20 TeV, cosmic-ray nuclei from Z = 1 through Z ∼ 40, and gamma rays over the range 1 GeVâ€"10 TeV. CGBM observes gamma rays from 7 keV to 20 MeV. The combined CAL-CGBM instrument has conducted a search for gamma-ray bursts (GRBs) since 2015 October. We report here on the results of a search for X-ray/gamma-ray counterparts to gravitational-wave events reported during the LIGO/Virgo observing run O3. No events have been detected that pass all acceptance criteria. We describe the components, performance, and triggering algorithms of the CGBMâ€"the two Hard X-ray Monitors consisting of LaBr3(Ce) scintillators sensitive to 7 keVâ€"1 MeV gamma rays and a Soft Gamma-ray Monitor BGO scintillator sensitive to 40 keVâ€"20 MeVâ€"and the high-energy CAL consisting of a charge detection module, imaging calorimeter, and the fully active total absorption calorimeter. The analysis procedure is described and upper limits to the time-averaged fluxes are presented. [ABSTRACT FROM AUTHOR]

Abstract: The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3g/cm2. Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178GeV/n to 1.334GeV/n were made during the 28.7h of flight. This paper presents the measured energy spectra and their ratio, 2H/1H. The results are also compared with previous measurements and theoretical predictions. [Copyright &y& Elsevier]

Abstract: Development of a balloon to fly at higher altitudes is one of the most attractive challenges for scientific balloon technologies. After reaching the highest balloon altitude of 53.0km using the 3.4μm film in 2002, a thinner balloon film with a thickness of 2.8μm was developed. A 5000m3 balloon made with this film was launched successfully in 2004. However, three 60,000m3 balloons with the same film launched in 2005, 2006, and 2007, failed during ascent. The mechanical properties of the 2.8μm film were investigated intensively to look for degradation of the ultimate strength and its elongation as compared to the other thicker balloon films. The requirement of the balloon film was also studied using an empirical and a physical model assuming an axis-symmetrical balloon shape and the static pressure. It was found that the film was strong enough. A stress due to the dynamic pressure by the wind shear is considered as the possible reason for the unsuccessful flights. A 80,000m3 balloon with cap films covering 9m from the balloon top will be launch in 2011 to test the appropriateness of this reinforcement. [Copyright &y& Elsevier]

Abstract: The tandem balloon system has been known as a candidate system for long duration flight balloons. In this paper, the properties of the system are analytically studied in a new way by introducing an extendable suspension wire in the Sky Anchor configuration, which consists of a zero-pressure main balloon suspending a payload and a super-pressure balloon suspended below the payload. It was found that extension of the suspension wire between the payload and the super-pressure balloon can extend the capability of the tandem system; the altitude of the zero-pressure balloon can be changed without any consumables except some energy, and the day–night oscillation of the balloon altitude can be suppressed. This property is useful as the vehicle for long duration flights. It is also pointed out that the method to control the altitude of a balloon using an additional suspended super-pressure balloon can also be applied for super-pressure balloons. [Copyright &y& Elsevier]

Abstract: The first scientific flight of the BESS-Polar balloon-borne experiment was successfully carried out in December 2004 from Antarctica with the primary scientific objectives of searching for primordial antiparticles from the universe and making precision measurements of primary cosmic-ray fluxes. During the 8.5 day flight, the newly developed BESS-Polar spectrometer worked well and gathered data from 9×108 cosmic-ray events, showing its capability for making long-duration science observations. We have already started hardware development for the second experiment, which is expected to be a flight of more than 20 days during the next solar minimum period with the upgraded spectrometer. In this manuscript, progress on and prospects for the BESS-Polar experiment are described. [Copyright &y& Elsevier]

Abstract: The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) has been carried out to search for primordial antiparticles in cosmic rays. In ten flights from 1993 to 2004, it measured the cosmic-ray antiproton spectrum in the energy range 0.1–4.2GeV at various solar activity conditions. It also searched for antideuterons and antihelium nuclei, and it made precise measurement of cosmic-ray particle spectra. The BESS program has been extended to long duration balloon (LDB) flights in Antarctica (BESS-Polar) with the goal of achieving unprecedented sensitivity in the search for primordial antiparticles. This report describes recent results from BESS and progress of the BESS-Polar program. [Copyright &y& Elsevier]

Abstract: We measured atmospheric antiproton spectra in the energy range 0.2 to 3.4 GeV, at sea level and at balloon altitude in the atmospheric depth range 4.5 to 26 g/cm2. The observed energy spectra, including our previous measurements at mountain altitude, were compared with estimated spectra calculated on various assumptions regarding the energy distribution of antiprotons that interacted with air nuclei. [Copyright &y& Elsevier]

We have investigated the microwave oscillations due to a spin transfer effect induced by direct current in ferromagnetic nanocontact magnetoresistive (NCMR) elements with a current-perpendicular-to-plane spin-valve structure consisting of an FeCo/FeCo–AlOx nano-oxide layer/FeCo multilayer for the reference/spacer/free layers, respectively. Characteristic microwave oscillations were observed in the NCMR elements at different magnetization states induced by the application of a spin-polarized current, which are considered to be related to the introduction of a ferromagnetic NC to spacer layer (large interlayer coupling) and the resonance concerning the stability of the magnetization states of the free and reference layers around the NCs. A marvelously narrow full width at half maximum (FWHM) of l0–20 MHz is observed under a high applied magnetic field where the reference layer magnetization is slightly off axis relative to the pinned direction. By contrast, a wider FWHM of 80–600 MHz is observed at the magnetization state where the magnetization of the free layer just aligned to the antiparallel configuration against the magnetization of the reference layer. These characteristic results are discussed in terms of a spin dynamics mechanism induced by spin transfer torque in the free and reference layers around NCs. [ABSTRACT FROM AUTHOR]

The General Antiparticle Spectrometer (GAPS) is an upcoming balloon mission to measure low-energy cosmic-ray antinuclei during at least three ∼ 35-day Antarctic flights. With its large geometric acceptance and novel exotic atom-based particle identification, GAPS will detect ∼ 500 cosmic antiprotons per flight and produce a precision cosmic antiproton spectrum in the kinetic energy range of ∼ 0. 07 − 0. 21 GeV/ n at the top of the atmosphere. With these high statistics extending to lower energies than any previous experiment, and with complementary sources of experimental uncertainty compared to traditional magnetic spectrometers, the GAPS antiproton measurement will be sensitive to dark matter, primordial black holes, and cosmic ray propagation. The antiproton measurement will also validate the GAPS antinucleus identification technique for the antideuteron and antihelium rare-event searches. This analysis demonstrates the GAPS sensitivity to cosmic-ray antiprotons using a full instrument simulation and event reconstruction, and including solar and atmospheric effects. [ABSTRACT FROM AUTHOR]

LiteBIRD is a proposed CMB polarization satellite project to probe the inflationary B-mode signal. The satellite is designed to measure the tensor-to-scalar ratio with a 68 % confidence level uncertainty of $$\sigma _\mathrm{r}<10^{-3}$$ , including statistical, instrumental systematic, and foreground uncertainties. LiteBIRD will observe the full sky from the second Lagrange point for 3 years. We have a focal plane layout for observing frequency coverage that spans 40-402 GHz to characterize the galactic foregrounds. We have two detector candidates, transition-edge sensor bolometers and microwave kinetic inductance detectors. In both cases, a telecentric focal plane consists of approximately $$2\times 10^3$$ superconducting detectors. We will present the mission overview of LiteBIRD, the project status, and the TES focal plane layout. [ABSTRACT FROM AUTHOR]

Recent years have seen increased theoretical and experimental effort towards the first-ever detection of cosmic-ray antideuterons, in particular as an indirect signature of dark matter annihilation or decay. In contrast to indirect dark matter searches using positrons, antiprotons, or γ -rays, which suffer from relatively high and uncertain astrophysical backgrounds, searches with antideuterons benefit from very suppressed conventional backgrounds, offering a potential breakthrough in unexplored phase space for dark matter. This article is based on the first dedicated cosmic-ray antideuteron workshop, which was held at UCLA in June 2014. It reviews broad classes of dark matter candidates that result in detectable cosmic-ray antideuteron fluxes, as well as the status and prospects of current experimental searches. The coalescence model of antideuteron production and the influence of antideuteron measurements at particle colliders are discussed. This is followed by a review of the modeling of antideuteron propagation through the magnetic fields, plasma currents, and molecular material of our Galaxy, the solar system, the Earth’s geomagnetic field, and the atmosphere. Finally, the three ongoing or planned experiments that are sensitive to cosmic-ray antideuterons, BESS, AMS-02, and GAPS, are detailed. As cosmic-ray antideuteron detection is a rare event search, multiple experiments with orthogonal techniques and backgrounds are essential. Therefore, the combination of AMS-02 and GAPS antideuteron searches is highly desirable. Many theoretical and experimental groups have contributed to these studies over the last decade, this review aims to provide the first coherent discussion of the relevant dark matter theories that antideuterons probe, the challenges to predictions and interpretations of antideuteron signals, and the experimental efforts toward cosmic antideuteron detection. [ABSTRACT FROM AUTHOR]

The General Antiparticle Spectrometer (GAPS) is a novel approach for indirect dark matter searches that exploits cosmic antiparticles, especially antideuterons. The GAPS antideuteron measurement utilizes distinctive detection methods using atomic X-rays and charged particles from the decay of exotic atoms as well as the timing and stopping range of the incoming particle, which together provide excellent antideuteron identification. Prior to the future balloon experiment, an accelerator test and a prototype flight were successfully conducted in 2005 and 2012 respectively, in order to verify the GAPS detection concept. This paper describes how the sensitivity of GAPS to antideuterons was estimated using a Monte Carlo simulation along with the atomic cascade model and the Intra-Nuclear Cascade model. The sensitivity for the GAPS antideuteron search obtained using this method is 2.0 × 10 − 6 [m − 2 s − 1 sr − 1 (GeV/ n ) − 1 ] for the proposed long duration balloon program (LDB, 35 days × 3 flights), indicating that GAPS has a strong potential to probe a wide variety of dark matter annihilation and decay models through antideuteron measurements. GAPS is proposed to fly from Antarctica in the austral summer of 2019–2020. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 50-year-old woman who was admitted to the hospital complaining abdominal pain, vomiting, and diarrhea. She was diagnosed with rupture of the pancreaticoduodenal artery aneurysms with segmental arterial mediolysis (SAM). The bleeding stopped, and the patient's symptoms disappeared when transcatheter coil embolization of the SAM was successfully performed.

LiteBIRD is a next-generation satellite mission to measure the polarization of the cosmic microwave background (CMB) radiation. On large angular scales the B-mode polarization of the CMB carries the imprint of primordial gravitational waves, and its precise measurement would provide a powerful probe of the epoch of inflation. The goal of LiteBIRD is to achieve a measurement of the characterizing tensor to scalar ratio $$r$$ to an uncertainty of $$\delta r=0.001$$ . In order to achieve this goal we will employ a kilo-pixel superconducting detector array on a cryogenically cooled sub-Kelvin focal plane with an optical system at a temperature of 4 K. We are currently considering two detector array options; transition edge sensor (TES) bolometers and microwave kinetic inductance detectors. In this paper we give an overview of LiteBIRD and describe a TES-based polarimeter designed to achieve the target sensitivity of 2 $$\upmu $$ K arcmin over the frequency range 50-320 GHz. [ABSTRACT FROM AUTHOR]

Abstract: The general antiparticle spectrometer (GAPS) experiment is a proposed indirect dark matter search focusing on antiparticles produced by WIMP (weakly interacting massive particle) annihilation and decay in the Galactic halo. In addition to the very powerful search channel provided by antideuterons (Donato et al., 2000, 2008) [1,2], (Vittino et al.) [3], (Fornengo, 2013) [4], GAPS has a strong capability to measure low-energy antiprotons ( 0.25GeV) as dark matter signatures. This is an especially effective means for probing light dark matter, whose existence has been hinted at in the direct dark matter searches, including the recent result from the CDMS-II experiment (Agnese, 2013) [5]. While severely constrained by LUX and other direct dark matter searches (Akerib et al.) [6], light dark matter candidates are still viable in an isospin-violating dark matter scenario and halo-independent analysis (Del Nobile et al.) [7,8]. Along with the excellent antideuteron sensitivity, GAPS will be able to detect an order of magnitude more low-energy antiprotons, compared to BESS (Abe et al., 2012) [9], (Orito et al., 2000) [10], PAMELA (Adriani et al., 2010) [11] and AMS-02 (Casaus, 2009) [12], providing a precision measurement of low-energy antiproton flux and a unique channel for probing light dark matter models. Additionally, dark matter signatures from gravitinos and Kaluza–Klein right-handed neutrinos as well as evidence of primordial black hole evaporation can be observed through low-energy antiproton search. [Copyright &y& Elsevier]

Abstract: The General AntiParticle Spectrometer experiment (GAPS) is foreseen to carry out a dark matter search using low-energy cosmic ray antideuterons at stratospheric altitudes with a novel detection approach. A prototype flight from Taiki, Japan was carried out in June 2012 to prove the performance of the GAPS instrument subsystems (Lithium-drifted Silicon tracker and time-of-flight) and the thermal cooling concept as well as to measure background levels. The flight was a success and the stable flight operation of the GAPS detector concept was proven. During the flight about charged particle triggers were recorded, extensive X-ray calibrations of the individual tracker modules were performed by using an onboard X-ray tube, and the background level of atmospheric and cosmic X-rays was measured. The behavior of the tracker performance as a function of temperature was investigated. The tracks of charged particle events were reconstructed and used to study the tracking resolution, the detection efficiency of the tracker, and coherent X-ray backgrounds. A timing calibration of the time-of-flight subsystem was performed to measure the particle velocity. The flux as a function of flight altitude and as a function of velocity was extracted taking into account systematic instrumental effects. The developed analysis techniques will form the basis for future flights. [Copyright &y& Elsevier]

Abstract: The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6h, with over 3h at float altitude . Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded. [Copyright &y& Elsevier]

Abstract: The General Antiparticle Spectrometer (GAPS) is a new approach to the indirect detection of dark matter. It relies on searching for primary antideuterons produced in the annihilation of dark matter in the galactic halo. Low energy antideuterons produced through Standard Model processes, such as collisions of cosmic-rays with interstellar baryons, are greatly suppressed compared to primary antideuterons. Thus a low energy antideuteron search provides a clean signature of dark matter. In GAPS antiparticles are slowed down and captured in target atoms. The resultant exotic atom deexcites with the emission of X-rays and annihilation pions, protons and other particles. A tracking geometry allows for the detection of the X-rays and particles, providing a unique signature to identify the mass of the antiparticle. A prototype detector was successfully tested at the KEK accelerator in 2005, and a prototype GAPS balloon flight is scheduled for 2011. This will be followed by a full scale experiment on a long duration balloon from Antarctica in 2014. We discuss the status and future plans for GAPS. [Copyright &y& Elsevier]

Abstract: The balloon-borne experiment with a superconducting spectrometer (BESS) has performed cosmic-ray observations as a US–Japan cooperative space science program, and has provided fundamental data on cosmic rays to study elementary particle phenomena in the early Universe. The BESS experiment has measured the energy spectra of cosmic-ray antiprotons to investigate signatures of possible exotic origins such as dark matter candidates or primordial black holes, and searched for heavier antinuclei that might reach Earth from antimatter domains formed in the early Universe. The apex of the BESS program was reached with the Antarctic flight of BESS-Polar II, during the 2007–2008 Austral Summer, that obtained over 4.7billion cosmic-ray events from 24.5days of observation. The flight took place at the expected solar minimum, when the sensitivity of the low-energy antiproton measurements to a primary source is greatest. Here, we report the scientific results, focusing on the long-duration flights of BESS-Polar I (2004) and BESS-Polar II (2007–2008). [Copyright &y& Elsevier]

Abstract: The General AntiParticle Spectrometer (GAPS) is a novel approach for indirect dark matter searches that exploits cosmic antideuterons. GAPS complements existing and planned direct dark matter searches as well as other indirect techniques, probing a different and unique region of parameter space in a variety of proposed dark matter models. The GAPS method involves capturing antiparticles into a target material with the subsequent formation of an excited exotic atom. The exotic atom decays with the emission of atomic X-rays and pions from the nuclear annihilation, which uniquely identifies the captured antiparticle. This technique has been verified through the accelerator testing at KEK in 2004 and 2005. The prototype flight is scheduled from Hokkaido, Japan in 2011, preparatory for a long duration balloon flight from the Antarctic in 2014. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report searches for antihelium in cosmic rays using two recently flown magnetic rigidity spectrometers. BESS-TeV had extended rigidity with an MDR of 1.4TV and had a flight duration of one day. BESS-Polar was optimized for collecting power. It was flown for 8.5 days and had an MDR of 240GV. The former flight allows us to explore a previously unexplored rigidity band and the latter flight yields a factor of three improvement in the overall BESS limit. No antihelium candidate was found in the rigidity ranges of 1–500GV, and 0.6–20GV, among 7×104 events taken with BESS-TeV, and 8×106 events taken with BESS-Polar, respectively. [Copyright &y& Elsevier]

Abstract: We measured low energy cosmic-ray proton and helium spectra in the kinetic energy range 0.215–21.5GeV/n at different solar activities during a period from 1997 to 2002. The observations were carried out with the BESS spectrometer launched on a balloon at Lynn Lake, Canada. A calculation for the correction of secondary particle backgrounds from the overlying atmosphere was improved by using the measured spectra at small atmospheric depths ranging from 5 through 37g/cm2. The uncertainties including statistical and systematic errors of the obtained spectra at the top of atmosphere are 5–7% for protons and 6–9% for helium nuclei in the energy range 0.5–5GeV/n. [Copyright &y& Elsevier]

Abstract: The Balloon Borne Experiment with a Superconducting Spectrometer (BESS) has measured the energy spectrum of cosmic-ray antiprotons between 0.18 and 4.20 GeV in eight flights between 1993 and 2002. Above about 1 GeV, models in which antiprotons are secondary products of the interactions of primary cosmic rays with the interstellar gas agree with the BESS antiproton spectrum. Below 1 GeV, the data show a possible excess antiproton flux compared to secondary model predictions, suggesting the presence of an additional source of antiprotons. The antiproton/proton ratios measured between 1993 and 1999, during the Sun’s positive-polarity phase, are consistent with simple models of solar modulation. However, results from the 2000 flight, following the solar magnetic field reversal, show a sudden increase in the antiproton/proton ratio and tend to favor a charge-sign-dependent drift model. To extend BESS measurements to lower energies, an evolutionary instrument, BESS-Polar, is under construction for polar flight in 2004. [Copyright &y& Elsevier]

Primary and atmospheric cosmic-ray spectra were precisely measured with the BESS-TeV spectrometer. The spectrometer was upgraded from BESS-98 to achieve seven times higher resolution in momentum measurement. We report absolute fluxes of primary protons and helium nuclei in the energy ranges, 1–540 GeV and 1–250 GeV/n, respectively, and absolute flux of atmospheric muons in the momentum range 0.6–400 GeV/c. [Copyright &y& Elsevier]

In order to investigate elementary particle phenomena in the early Universe, the BESS-polar experiment is proposed. It will study low-energy antiprotons and search for antinuclei in the galactic cosmic rays at the constant altitude maintained by a scientific balloon. A new superconducting spectrometer is being developed for long-duration balloon flights. In order to extend the detectable energy range of antiprotons down to 100 MeV, the thickness of materials along the trajectory of the incident particle is minimized. The spectrometer will be completed in 2003, and the first long-duration flight is planned in 2004. [Copyright &y& Elsevier]

Balloon-borne Experiment with a Superconducting Spectrometer (BESS) is a balloon-borne spectrometer to study elementary particle phenomena in the early Universe as well as the origin and the propagation of cosmic radiation. The instrument has a unique feature of a thin superconducting solenoid which enables a large acceptance with a cylindrical configuration. Nine balloon flights have been successfully carried out since 1993. In 2002, the detector was upgraded as the BESS-TeV spectrometer to extend primary cosmic-ray spectra up to 1 TeV. For further studies of low-energy antiprotons, a new spectrometer, BESS-Polar, with a ultra-thin superconducting solenoid is being developed for long duration balloon flights in Antarctica. [Copyright &y& Elsevier]