86 research outputs found
Challenges for the directional dark matter direct detection
Directional methods have been considered to provide a solid proof for the
direct detection of the dark matter. Gaseous time-projection-chambers (TPCs)
are the most mature devices for directional dark matter searches although there
still exist several challenges to overcome. This paper reviews the history,
current challenges and future prospects of the gaseous TPCs for directional
dark matter searches.Comment: 12 pages, 7figures, prepared for the submission to Journal of
Advanced Instrumentation in Scienc
Probing GHz Gravitational Waves with Graviton-magnon Resonance
A novel method for extending frequency frontier in gravitational wave
observations is proposed. It is shown that gravitational waves can excite a
magnon. Thus, gravitational waves can be probed by a graviton-magnon detector
which measures resonance fluorescence of magnons. Searching for gravitational
waves with a wave length by using a ferromagnetic sample with a
dimension , the sensitivity of the graviton-magnon detector reaches spectral
densities, around $5.4 \times 10^{-22} \times (\frac{l}{\lambda /2\pi})^{-2} \
[{\rm Hz}^{-1/2}]8.6 \times 10^{-21} \times (\frac{l}{\lambda
/2\pi})^{-2} \ [{\rm Hz}^{-1/2}]$ at 8.2 GHz, respectively.Comment: 5 pages, 1 figure, minor change
Directional direct detection of light dark matter up-scattered by cosmic-rays from direction of the Galactic center
Dark matters with MeV- or keV-scale mass are difficult to detect with
standard direct search detectors. However, they can be searched for by
considering the up-scattering of kinetic energies by cosmic-rays. Since dark
matter density is higher in the central region of the Galaxy, the up-scattered
dark matter will arrive at Earth from the direction of the Galactic center.
Once the dark matter is detected, we can expect to recognize this feature by
directional direct detection experiments. In this study, we simulate the
nuclear recoils of the up-scattered dark matter and quantitatively reveal that
a large amount of this type of dark matter is arriving from the direction of
the Galactic center. Also, we have shown that the characteristic signatures of
the up-scattered dark matter can be verified with more than 5
confidence levels in the case of all assumed target atoms in the scope of the
future upgrade of the directional detectors.Comment: 16 pages, 64 figure
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
Performance of a micro-TPC for a time-resolved neutron PSD
We report on the performance of a micro-TPC with a micro pixel
chamber(-PIC) readout for a time-resolved neutron position-sensitive
detector(PSD). Three-dimensional tracks and the Bragg curves of protons with
energies of around 1 MeV were clearly detected by the micro-TPC. More than 95%
of gamma-rays of 511 keV were found to be discriminated by simple analysis.
Simulation studies showed that the total track length of proton and triton
emitted from the (n,p(573 keV)) reaction is
about 1.2 cm, and that both particles have large energy losses () in 1 atm Ar++He(). These values
suit the current performance of the micro-TPC, and we conclude that a
time-resolved neutron PSD with spatial resolution of sub-millimeters shall be
developed as an application of the micro-TPC.Comment: 13 pages, 10 figures, to appear in NIM
Development of a low-alpha-emitting {\mu}-PIC for NEWAGE direction-sensitive dark-matter search
NEWAGE is a direction-sensitive dark-matter-search experiment that uses a
micro-patterned gaseous detector, or {\mu}-PIC, as the readout. The main
background sources are {\alpha}-rays from radioactive contaminants in the
{\mu}-PIC. We have therefore developed a low-alpha-emitting {\mu}-PICs and
measured its performances. We measured the surface {\alpha}-ray emission rate
of the {\mu}-PIC in the Kamioka mine using a surface {\alpha}-ray counter based
on a micro TPC.Comment: 6 pages, 4 figure
Simulation study of electron drift and gas multiplication in Micro Pixel Chamber
The physical processes of charge collection and gas multiplication of a Micro
Pixel Chamber (mu-PIC) were studied in detail using a three-dimensional
simulation. The collection efficiencies of primary electrons and gas
multiplication factors were calculated for several electrode structures. Based
on those studies, we analyzed the optimization of the electrode structure of
the mu-PIC, in order to obtain a high gas gain of more than 10^4 and a
simultaneous suppression of discharges. Consequently, we found that these
characteristics strongly depend on the substrate thickness and the anode
diameter of the mu-PIC. In addition, a gas gain of 10^5 would be expected for a
mu-PIC having a thick substrate of > 150um.Comment: 16 pages, 14 figures, Submitted to Nucl. Instr. Methods
Measurement of radon emanation and impurity adsorption from argon gas using ultralow radioactive zeolite
The amount of radioactive impurities contaminated in the detector gases is
required to be kept at a very low level for rare event particle physics such as
dark matter and neutrino observation experiments. Zeolite is a well-known
adsorbent material and is one of the possible candidates for removing
impurities from these gases. At the same time, the amount of radioactive
impurities released from the adsorbent material needs to be sufficiently small.
In this paper, a development of a new ultralow radioactive zeolite as a product
of the selection of ultralow radioactive materials is reported. Results on the
radon emanation and impurity adsorption from argon gas measurements are also
described.Comment: 8 pages, 7 figure
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