103 research outputs found
Particle Acceleration and Cosmic-Ray Origin in the Galaxy
In 1990's Very High Energy Gamma-ray Astrophysics has dramatically advanced
due to the Imaging Air \v{C}erenkov Telescopes(IACTs). After the first
detection of TeV gamma-ray emission from the Crab nebula in 1989, several type
of TeV gamma-ray sources, Active Galactic Nuclei(AGN), young pulsar, and
SuperNova Remnant(SNR), have been detected. In those discoveries, recent
detections of both synchrotron X-rays and TeV gamma-ray emissions from several
SNRs are very significant. SNR has been widely believed to be an unique
candidate of galactic cosmic-ray origin since the beginning of cosmic-ray
physics, whereas little observational evidences have been reported so far.
Those are expected to be a clue of not only the galactic cosmic-ray origin but
also the understanding of the particle acceleration due to a diffusive shock.
Here I present the recent results obtained by our group, CANGAROO, about the
evidences of electron and proton acceleration in SNRs.Comment: 9 pages, 9 figures, to appear in proceedings of the conference " The
International Symposium on Science of Super-Strong Field Interactions" held
in Japan Hayama, March 200
Imaging Gaseous Detector based on Micro Processing Technology
The development of gaseous detectors has been exciting again since the
appearance of a MicroStrip Gas Chamber(MSGC) in 1988, which is made using a
micro-electronics technology. These days lots of variations of the advanced
gaseous detectors are being intensively studied in the world.
We have developed the two-dimensional MSGC having a 10 cm square detection
area and the ultra fast readout system for a real time X-ray imaging. The MSGC
was made using Multi-Chip Module (MCM) technology, and has a very thin
substrate of 17 m, lots of thin anodes and back strips both with 200
m pitches. This enables us to get fast digital X-ray images with recording
both the timing and an energy of each X-ray photon. In addition, an
intermediate gas multiplier has been realized using a capillary plate having a
conductive surface of a capillary. The MSGC combined with the conductive
capillary plate can be steadily operated with a high gain under intense
irradiation. Here we also report new approaches of X-ray crystal structure
analyses using timing information obtained by the MSGC.Comment: 14 papges, 10 figures, to appear in the proceedings of Solid State
Detectors for 21st Century (Nucl. Instru. and Meth. A
Performance of large area Micro Pixel Chamber
A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber
(micro-PIC)" has been developed. This detector is based on double sided printed
circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with
65536 pixel anodes of 400um pitch on a 100um thick insulating substrate.
Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was
obtained with argon ethane (8:2) gas mixture. This gain is high enough to
detect minimum ionizing particles with such a small electrode pitch. Although
several discharges occurred during 65 hours continuous operation, the detectors
have kept stable operation with high gain. The micro-PIC is a useful detector
for many applications e.g. X-ray, gamma ray, and charged particle imaging. The
micro electrode structure allows us to measure directions of primary electrons
due to incident X-rays or gamma rays, which provide a strong method for X-ray
polarimetry and gamma-ray imaging.Comment: 4 pages, 8 figures, to appear in the proceedings of 6th International
Conference on Position Sensitive Detectors, 9-13 Sep 2002, Leicester, UK
(Nucl. Instr. and Meth. A
Performance of the TPC with Micro Pixel Chamber Readout: micro-TPC
Micro-TPC, a time projection chamber(TPC) with micro pixel chamber(-PIC)
readout was developed for the detection of the three-dimensional fine(sub-m
illimeter) tracks of charged particles. We developed a two-dimensional position
sensitive gaseous detector, or the -PIC, with the detection area of
1010 cm and 65536 anode electrodes of 400 m pitch. We
achieved the gas gain of over 10000 without any other multipliers. With the
pipe-line readout system specially developed for the -PIC, we detected
X-rays at the rate as high as 7.7 Mcps. We attached a drift cage with an 8 cm
drift length to the -PIC and developed a micro-TPC. We measured the basic
performances of the micro-TPC and took three-dimensional tracks of electrons.
We also developed a prototype of the MeV gamma-ray imaging detector which is a
hybrid of the micro-TPC and NaI(Tl) scintillators and confirmed its concept by
reconstructing the obtained data.Comment: 6 pages 16 figures, submitted for IEEE/TNS 200
Observation of MeV-Gamma-Rays from relativistic electron precipitation with Balloon Borne Experiment around the Northern Polar Cap
第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月15日(火) 国立極地研究所 2階大会議
Performance of a Time-Projection-Chamber with a Large-Area Micro-Pixel-Chamber Readout
A micro time-projection-chamber (micro-TPC) with a detection volume of
23*28*31 cm^3 was developed, and its fundamental performance was examined. The
micro-TPC consists of a micro pixel chamber with a detection area of 31*31 cm^2
as a two-dimensional imaging device and a gas electron multiplier with an
effective area of 23*28 cm^2 as a pre-gas-multiplier. The micro-TPC was
operated at a gas gain of 50,000, and energy resolutions and spatial
resolutions were measured.Comment: 4 pages, 7 figures, proceedings of IWORID
Development of a time projection chamber with micro pixel electrodes
A time projection chamber (TPC) based on a gaseous chamber with micro pixel
electrodes (micro-PIC) has been developed for measuring three-dimensional
tracks of charged particles. The micro-PIC with a detection area of 10 cm
square consists of a double-sided printing circuit board. Anode pixels are
formed with 0.4 mm pitch on strips aligned perpendicular to the cathode strips
in order to obtain a two-dimensional position. In the TPC with drift length of
8 cm, 4 mm wide field cage electrodes are aligned at 1mm spaces and a uniform
electric field of about 0.4 kV/cm is produced. For encoding of the
three-dimensional position a synchronous readout system has been developed
using Field Programmable Gate Arrays with 40 MHz clock. This system enables us
to reconstruct the three-dimensional track of the particle at successive points
like a cloud chamber even at high event rate. The drift velocity of electrons
in the TPC was measured with the tracks of cosmic muons for three days, during
which the TPC worked stably with the gas gain of 3000. With a radioisotope of
gamma-ray source the three-dimensional track of a Compton scattered electron
was taken successfully.Comment: 4 pages, 7 figures, to appear in the proceedings of 6th International
Conference on Position Sensitive Detectors, 9-13 Sep 2002, Leicester, UK
(Nucl. Instr. and Meth. A
Study of Negative-Ion TPC Using {\mu}-PIC for Directional Dark Matter Search
Negative-ion time projection chambers(TPCs) have been studied for low-rate
and high-resolution applications such as dark matter search experiments.
Recently, a full volume fiducialization in a self-triggering TPC was realized.
This innovative technology demonstrated a significant reduction in the
background with MWPC-TPCs. We studied negative-ion TPC using the {\mu}-PIC+GEM
system and obtained sufficient gas gain with CSgas and SF gas at
low pressures. We expect an improvement in detector sensitivity and angular
resolution with better electronics
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