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T. Aramaki,
S. K. Chan,
W. W. Craig,
L. Fabris,
F. Gahbauer, C. J. Hailey,
J. E. Koglin,
N. Madden,
K. Mori,
H. T. Yu,
K. P. Ziock
[show abstract]
[hide abstract]
ABSTRACT: The General AntiParticle Spectrometer (GAPS) is a novel approach for indirect
dark matter searches that exploits cosmic antideuterons. GAPS utilizes a
distinctive detection method using atomic X-rays and charged particles from the
exotic atom as well as the timing, stopping range and dE/dX energy deposit of
the incoming particle, which provides excellent antideuteron identification.
Prior to the future balloon experiment, an accelerator test was conducted in
2004 and 2005 at KEK, Japan, in order to precisely measure the X-ray yields of
antiprotonic exotic atoms formed with different target materials. The X-ray
yields of the exotic atoms with Al and S targets were obtained as $\sim$ 75%,
which are higher than were previously assumed in. A simple, but comprehensive
cascade model has been developed not only to evaluate the measurement results
but also to predict the X-ray yields of the exotic atoms formed with any
materials in the GAPS instrument. The cascade model is extendable to any kind
of exotic atom (any negatively charged cascading particles with any target
materials), and it was compared and validated with other experimental data and
other cascade models for muonic and antiprotonic exotic atoms. The X-ray yields
of the antideuteronic exotic atoms are predicted with a simple cascade model
and the sensitivity for the GAPS antideuteron search is estimated as 1.3
$\times 10^{-6}$ [m$^{-2}$s$^{-1}$sr$^{-1}$(GeV/n)$^{-1}$] for the proposed
long duration balloon program, which suggests that GAPS has a strong potential
to detect antideuterons as a dark matter signature. A GAPS prototype flight
(pGAPS) was launched successfully from the JAXA/ISAS balloon facility in
Hokkaido, Japan in summer 2012 and a proposed GAPS science flight is to fly
from Antarctica in the austral summer of 2017-2018.
03/2013;
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S. A. I. Mognet,
T. Aramaki,
N. Bando,
S. E. Boggs,
P. von Doetinchem,
H. Fuke,
F. H. Gahbauer, C. J. Hailey,
J. E. Koglin,
N. Madden,
K. Mori,
S. Okazaki,
R. A. Ong,
K. M. Perez,
G. Tajiri,
T. Yoshida,
J. Zweerink
[show abstract]
[hide abstract]
ABSTRACT: The General Antiparticle Spectrometer (GAPS) experiment is a novel approach
for the detection of cosmic ray antiparticles. A prototype GAPS experiment
(pGAPS) 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 6 hours, with over 3
hours at float altitude (~33 km). Over one million cosmic ray triggers were
recorded and all flight goals were met or exceeded.
03/2013;
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[show abstract]
[hide abstract]
ABSTRACT: We report on recent accelerator testing of a prototype general antiparticle spectrometer (GAPS). GAPS is a novel approach for indirect dark matter searches that exploits the antideuterons produced in neutralino-neutralino annihilations. GAPS captures these antideuterons into a target with the subsequent formation of exotic atoms. These exotic atoms decay with the emission of X-rays of precisely defined energy and a correlated pion signature from nuclear annihilation. This signature uniquely characterizes the antideuterons. Preliminary analysis of data from a prototype GAPS in an antiproton beam at the KEK accelerator in Japan has confirmed the multi-X-ray/pion star topology and indicated X-ray yields consistent with prior expectations. Moreover our success in utilizing solid rather than gas targets represents a significant simplification over our original approach and offers potential gains in sensitivity through reduced dead mass in the target area. Comment: 18 pages, 9 figures, submitted to JCAP
09/2005;
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[show abstract]
[hide abstract]
ABSTRACT: Numerous reports have been made of features, either in emission or absorption, in the 10 - 1000 keV spectra of some gamma-ray bursts. Originally interpreted in the context of Galactic neutron star models as cyclotron line emission and $e^+ - e^-$ annihilation features, the recent demonstration that the majority of GRBs lie at cosmological distances make these explanations unlikely. In this letter, we adopt a relativistic fireball model for cosmological GRBs in which dense, metal rich blobs or filaments of plasma are entrained in the relativistic outflow. In the context of this model, we investigate the conditions under which broadband features, similar to those detected, can be observed. We find a limited region of parameter space capable of reproducing the observed GRB spectra. Finally, we discuss possible constraints further high-energy spectral observations could place on fireball model parameters. Comment: Accepted for publication in Astrophysical Journal Letters Four pages, 2 figures
05/1999;
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[show abstract]
[hide abstract]
ABSTRACT: The 2P3/2-2P1/2 fine-structure interval in hydrogenic iron and zinc has been determined in a beam-foil spectroscopy experiment. A novel technique utilising a dual-arm Johann spectrometer was used which allowed the measurements to be performed with high precision and high efficiency. The fine-structure splitting was determined to be 21.5+or-0.4 eV in hydrogenic iron and 38.2+or-0.8 eV in hydrogenic zinc compared with theoretical values of 21.2 and 37.9 eV, respectively, given by Mohr (1983). The result obtained for iron is in better agreement with theory than the previously reported measurements of Briand et al (1983-4).
Journal of Physics B Atomic and Molecular Physics 12/1998; 18(7):1443.
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[show abstract]
[hide abstract]
ABSTRACT: The hard x-ray (10-600 keV) sky is inherently time variable and yet has neither been surveyed nor monitored with a sensitive imaging telescope. The Energetic X-ray Imaging Survey Telescope (EXIST) is a mission concept, proposed for MIDEX, which would conduct the first imaging all-sky hard x-ray survey as well as provide a sensitive all sky monitor. With $\sim 60%$ sky coverage each orbit, and full sky coverage each 50 days, hard x-ray studies of gamma-ray bursts, AGN, galactic transients, x-ray binaries and accretion-powered pulsars can be conducted over a wide range of timescales. We summarize the scientific objectives of EXIST for both the survey and monitoring objectives. We describe the mission concept and the instrumentation approach, which would incorporate a large area array of Cd-Zn-Te (CZT) detectors, as well as some of our ongoing development of CZT array detectors.
01/1998;
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03/1997;
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[show abstract]
[hide abstract]
ABSTRACT: Wehave begun to study a mission to carry out the #rst high sensitivity imaging survey of the entire sky at hard x-ray energies #5-600 keV#. The Energetic X-ray Imaging Survey Telescope #EXIST# would include 2-4 large area coded aperture telescopes with o#set #elds of view allowing total exposures of # # 500 ksec and #ux sensitivities below 1 mCrab over the full sky in a year with time resolution from msec to months for each source as well as high spatial and spectral resolution for sources, transients and gamma-ray bursts. A pointed Observatory phase, with the telescopes co-aligned, would follow and achieve still greater sensitivities and temporal coverage, allowing the detailed study of virtually all classes of accretion sources #cataclysmic variables to quasars# as well as di#use galactic emission. The baseline concept originally proposed for the detector is a modularized array#4#4# of Cd-Zn-Te crystals #6.25 cm 2 each, or 100 cm 2 #module#. An arrayof5#5 modules, or 2500 cm 2 ...
03/1997;
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[show abstract]
[hide abstract]
ABSTRACT: Andromeda is a wide-#eld, imaging, hard X-ray#soft gamma-ray instrument capable of detecting gamma-ray bursts #GRBs# a factor #20 times fainter than GRO#BATSE. During 1-year of a two-year mission, it could determine whether GRBs are Galactic or cosmological in origin by searching for an excess of bursts towards the nearby Andromeda galaxy #M31#. As a pointed, imaging instrument with sensitivity in the 10---200 keV band signi#cantly better than previous coded-aperture instruments, Andromeda is capable of carrying out important secondary science objectives: for example, studying the soft-gamma-repeater and X-ray transient populations of M31 and the Galactic bulge. Andromeda is a coded aperture gamma-ray telescope consisting of a hexagonal coded mask coupled to an alkalihalide imaging scintillation detector, a #ight-proven technology adapted from the balloon-borne Caltech Gamma-Ray Imaging Payload #GRIP#. The new instrument is optimized for the 10#200 keV band and has 1:5 # angular resolution overa17 # FWHM #eld of view. Andromeda is designed to be a small, lowcost mission, and draws its design largely from existing instrumentation. Andromeda was submitted to the STEDI program, and will also be proposed as a NASA Small Explorer.
03/1997;
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W. W. Craig, C. J. Hailey,
J. Hong,
S. M. Kahn,
J. W. Keck,
R. McLean,
M. J. Pivovaroff,
G. Sprehn,
R. E. Wurtz,
K. P. Ziock,
F. A. Harrison,
J. G. Jernigan,
P. M. Lubin,
M. Seiffert
[show abstract]
[hide abstract]
ABSTRACT: We present the first arcminute images of the gamma-ray sky. These images
were taken with the Gamma Ray Arcminute Telescope and Imaging System
(GRATIS). Using a combination of rotated one-dimensional coded aperture
masks and a novel state of the art aspect reconstruction system we
imaged a number of gamma ray sources, including CenA and GRS 1915 during
the Fall 1995 Alice Springs, Australia balloon campaign. We discuss the
specifics of the observations and preliminary results. The performance
of the aspect system provides a straightforward development path to the
production of a system capable of the 1-3 arcsecond localizations
required for potential gamma-ray burst detection from either small
satellite or long duration balloon platforms.
11/1996; 28:1396.
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[show abstract]
[hide abstract]
ABSTRACT: GRABIT is the gamma-ray bar imaging telescope, a low-energy
gamma-ray (60-600 keV) imaging spectrometer that can be extended to a
large area at low cost. GRABIT has a gamma-ray position-resolution of 2
mm with an energy resolution typical of alkali-halide detectors (18% at
60 keV). The complete coded-aperture telescope will have arc-minute
angular resolution over a large field of view. In addition, the good
energy and angular resolutions are obtained over the full bandwidth of
the instrument
IEEE Transactions on Nuclear Science 03/1996; · 1.45 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The Gamma-Ray Arcminute Telescope Imaging System (GRATIS) is a
balloon-borne coded aperture experiment sensitive in the energy range 20
- 200 keV. This is the first experiment in this energy band capable of
resolving sources on arcminute scales. The design incorporates an array
of thirty-six imaging scintillation detectors coupled to one-dimensional
coded masks which collectively yield a two-dimensional map over a field
of view of 0.75 degrees. The payload is fully constructed and calibrated
and will be launched for the first time this coming Spring. In this
poster we present an overview of the conceptual design of the instrument
optics and detector system as well as laboratory data demonstrating the
imaging performance of the telescope. We also discuss our proposed
observing plan and present calculations of our expected sensitivity. A
companion paper will discuss the telesope guidance and pointing system.
11/1992; 24:1195.
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[show abstract]
[hide abstract]
ABSTRACT: The authors have developed a gamma-ray imaging system (GRIS) to
inspect for nuclear warheads by imaging the highly penetrating
gamma-radiation emitted by radioactive materials integral to warheads.
Such an image may be used to obtain the compliment of warheads aboard
the missile. The authors describe the GRIS operating principles and
capabilities, present data, and discuss the advantages and disadvantages
of such a system for arms control. Field results are presented from a
use of GRIS on an emplaced Peacekeeper missile. Improvements to GRIS in
light of the field trial results are presented
IEEE Transactions on Nuclear Science 09/1992; · 1.45 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Ascertaining the number of warheads on a missile-delivery systems by a remote, nonvisual inspection may be desirable in some arms-control verification scenarios. A gamma-ray imaging system (GRIS) has been developed to inspect for nuclear warheads by imaging the highly penetrating gamma-radiation emitted by radioactive materials integral to warheads. Such an image may be used to obtain the missile loadout. The authors describe the GRIS's operating principles and capabilities, present data, and discuss the advantages and disadvantages of such a system for arms control. They also present field results where GRIS was used on an emplaced Peacekeeper missile. Improvements to GRIS in light of the field trial results are presented.< >
Nuclear Science Symposium and Medical Imaging Conference, 1991., Conference Record of the 1991 IEEE; 12/1991
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[show abstract]
[hide abstract]
ABSTRACT: We have constructed a high‐resolution x‐ray image intensifier (XRII) for use in atomic physics. The XRII consists of an alkali halide scintillator crystal coupled by a fiber optic to a proximity focused microchannel plate stack with a bialkali photocathode and wedge and strip readout. The useful area of the detector is 12 cm<sup>2</sup>. We have measured full width half maximum spatial resolutions at 22 keV of 300 μm and at 122 keV of 600 μm with 0.5‐mm‐thick and 1.6‐mm‐thick CsI(Na) crystals, respectively. With NaI(Tl) crystals, x‐ray arrival times can be determined with sub‐100 ns resolution. In this paper we present the detailed performance of the XRII as well as a brief discussion of the theory of photoelectron limited fast timing.
Review of Scientific Instruments 09/1990; · 1.37 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We report a novel, imaging, low-energy (.1-10 MeV) gamma-ray spectrometer. This device has excellent position resolution ({approximately}2 mm {at} 350 keV), near unity quantum efficiency, and alkali halide-type energy resolution at an extremely low cost per unit area. This is possible through the separation of the energy and position sensing functions in an alkali halide-based gamma-ray detector. 5 refs., 6 figs.
08/1989
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T. Aramaki,
S.E. Boggs,
W.W. Craig,
H. Fuke,
F. Gahbauer, C.J. Hailey,
J.E. Koglin,
N. Madden,
K. Mori,
R.A. Ong,
T. Yoshida
[show abstract]
[hide abstract]
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.
Advances in Space Research.
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[show abstract]
[hide abstract]
ABSTRACT: Shields capable of suppressing neutron-induced background in new classes of γ-ray detectors such as CdZnTe are becoming important for a variety of reasons. These include a high cross section for neutron interactions in new classes of detector materials as well as the inefficient vetoing of neutron-induced background in conventional active shields. We have previously demonstrated through Monte-Carlo simulations how our new approach, supershields, is superior to the monolithic, bi-atomic neutron shields which have been developed in the past. We report here on the first prototype models for supershields based on boron and hydrogen. We verify the performance of these supershields through laboratory experiments. These experimental results, as well as measurements of conventional monolithic neutron shields, are shown to be consistent with Monte-Carlo simulations. We discuss the implications of this experiment for designs of supershields in general and their application to future hard X-ray/γ-ray experiments.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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J.E. Koglin,
T. Aramaki,
W.W. Craig,
L. Fabris,
F. Gahbauer, C.J. Hailey,
F.J. Jou,
N. Madden,
K. Mori,
H.T. Yu,
K.P. Ziock
[show abstract]
[hide abstract]
ABSTRACT: We report on recent accelerator testing of a prototype general antiparticle spectrometer (GAPS). GAPS is a novel approach for indirect dark matter searches that exploits the antideuterons produced in neutralino-neutralino annihilations. Many supersymmetry models, as well as other models based on extra dimensions, predict a primary antideuteron flux from dark matter annihilation that is much greater than the secondary and tertiary background sources at low energies. The GAPS method involves capturing antiparticles in a target material into excited energy states. The X-rays that are emitted as the antiparticle cascades to lower energy states before the exotic atom decays serve as a fingerprint that uniquely identifies the mass of the captured antiparticle. This approach provides large area and field of view in addition to excellent background rejection capability. Analysis of the performance of a prototype GAPS tested in an antiproton beam at the KEK accelerator in Japan in 2004 and 2005 are presented.
Nuclear Physics B - Proceedings Supplements.
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H. Fuke,
J.E. Koglin,
T. Yoshida,
T. Aramaki,
W.W. Craig,
L. Fabris,
F. Gahbauer, C.J. Hailey,
F.J. Jou,
N. Madden,
K. Mori,
H.T. Yu,
K.P. Ziock
[show abstract]
[hide abstract]
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.
Advances in Space Research.
