Astroparticle Physics Laboratory
Department of Physics
Electrical and Computer Engineering
Yokohama National University
|Access| Links| Contact|Site map|Japanese|
HOME

RESEARCH
About cosmic ray
Tibet ASg project
CALET project
People
Pictures
Presetations
Publications Papers
Doctoral thesis , Master's thesis, Graduation thesis
Lists
Close-up


Research of the space with cosmic-rays
Cosmic rays are energetic particles carrying various information from space. We study space phenomenon by both observing cosmic rays and numerical simulation method. In addition , we are developing radiation detectors and the electronics to observe cosmic rays.
Doctoral Program
Our laboratory participates in the TibetAS gamma experiment. The TibetAS gamma experiment allows gamma ray astronomical observation with the highest sensitivity with energy region over tens of tera eV and it is possible to research such as pulsar nebula, supernova remnant, galactic diffusion gamma ray. In addition, student can get Ph.D (Science) with a unique theme such as research on cosmic ray chemical composition, solar or galactic magnetic field, and thunder studies using cosmic ray air shower.
  Admissions Information   Contact Lab
What's new

Budget of "JSPS Bilateral Joint Research Projects, Open Partnership Joint Research Projects"
(May, 2018)
"Search for 100 TeV gamma-ray sources and measurement of cosmic ray spectra and study of the high energy astrophysical phenomena"

Pertner : Universidad Mayor de San Andres(Bolibia)
period: pril 1, 2018 - March 31, 2020

We are studying on the unresolved question about the origin of cosmic rays exceeding the peta electron volt and high energy astronomical phenomena such as "PeVatron". For this purpose, we are preparing an hyghbrid experiment("ALPACA project") using both air shower array type cosmic ray telescope with wide-field of view and large water Cherenkov type muon detector in the Bolivian Andes plateau. This detector make possible to search for gamma rays of south hemshper of galaxy with the world's highest sensitivity in the 100 Tera Electron Volt range. In addition, the hyghbrid detector with the addition of the air shower core detector can also perform precise measurement of cosmic ray chemical composition from protons to iron in the peta electron volt range. We are aiming for equipment construction and measurement start during application period.
Observation site: Cerro Estuqueria, halfway up Mt. Chacaltaya, Bolivia\ (Southern latitude; 16deg. 23min., west longitude; 68deg.08min., altitude 4740 m)


Presentation at research meeting (April, 2018)
2017 HIMAC Collaborative Researche meeting

"(17H384) Study of radio waves in transition radiation process using heavy ion beam" Y.Katayose, T.Sasaki, T.Asaba, M.Wakamatsu, S.Kodaira
(Hotel Port Chiba, April 16th, 2018)

In order to investigate the characteristics of radio waves due to the transitional radiation process, we measured radio waves with frequencies from several tens of MHz to approximately 500 MHz by irradiating a heavy ion beam on the target material.  As a result of irradiating the helium ion beam with energy of 6 MeV/u on the polypropylene film, a slight signal increase in the range of 50 MHz to 100 MHz was observed against the background noise. When the direction of the antenna was changed, there was also a change in intensity, so this signal may possibly be radio waves due to transitional radiation.


Master's thesis presentation of M1(March 7th and 8th , 2018)
T.Sasaki(M1) "Research of radio waves by transition radiation process using accelerator beam"
M.Wakamatsu(M1) "Development of Front-end electronics for ALPACA experiment"
T.Asaba(M1) "Study of performance improvement for air shower observation devices with water Cherenkov detectors"

Presentation at meeting of Japan Phyics Society (March, 2018)
T.ASABA(M1)
"Study of performance improvement for air shower observation devices with water Cherenkov detectors"
(JPS 2018 Annual meeting, Tokyo university of science Noda campus, March 22th, 2018, 22aK307-8)

Presentation at research meeting (March, 2018)
Meeging of "雷雲と宇宙線の相互作用に伴う高エネルギー現象"
M.Suzuki(M2) "Study on particle acceleration mechanism in thunder cloud electric field using cosmic ray air shower array"
(ICRR of Tokyo university, Marth 3rd, 2018)


Presentation at research meeting(Feburary, 2018)
Meeging of "第二回 空気シャワー観測による宇宙線の起源探索勉強会"

o M.Suzuki(M2)
"Study on particle acceleration mechanism in thunder cloud electric field using cosmic ray air shower array"

o T.Asaba(M1)
"MonteCalro study of performance improvement for air shower observation using water Cherenkov detectors"
For high energy gamma ray astronomy huge detectors with high direction determination accuracy is important. In this research, we are aiming at improving angular resolution by hybrid measurement that adds water Cherenkov detector (WCD) array to an air shower array using plastic scintolators. WCD is highly sensitive to secondary gamma rays in an air shower, and can increase the total area inexpensively. We expect to realize twice the angle determination accuracy than the Tibet-IV air shower array. We developed determination mehtod of arrival direction using both detectors and evaluated the angle determination accuracy by montecalro simulation.

o Y. Katayose , "Study of Transition Radiation at Radio Frequencies from Cosmic Ray Showers"

(第二回 空気シャワー観測による宇宙線の起源探索勉強会, ICRR of Tokyo university, February 26th and 27th, 2018)

Graduation research presentation(February 22, 2018)
Y.Sengoku(B4)
"Simulation study on detection of TeV gamma ray from Geminga pulsar wind nebula with Tibet AS gamma experiment"
H.Mitsui(B4)
"Monte Carlo study of cosmic gamma-ray observation performance of ALPACA experiment"
K.Yagisawa(B4)
"Improvement of a bleeder circuit of PMT for water-Cherenkov detector for high energy cosmic ray heavy particle measuerment"
R.Mori(B4)
"Study of high energy cosmic ray nuclide selection method using deep learning"

Master's thesis presentation(February 14th, 2018)
M.Suzuki(M2)
"Study on particle acceleration mechanism in thunder cloud electric field using cosmic ray air shower array"
M.Kataoka(M2)
"Measurement of cosmic-ray light nuclei in TeV region with use of the air-shower core detector array"


Publication, PRL (January, 2018)
"Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun"
Phys. Rev. Lett. 120, 031101 (2018) , Published 16 January 2018    M. Amenomori et al. (The Tibet ASγ Collaboration)
Abstract:We analyze the Sun’s shadow observed with the Tibet-III air shower array and find that the shadow’s center deviates northward (southward) from the optical solar disk center in the “away” (“toward”) interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21stat±0.20syst (1.62±0.15stat±0.22syst) times larger than the model prediction. These demonstrate that the observed Sun’s shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

Presentation at meeting of Sciety of Atmospheric Electricity of Japan (January, 2018)
"Study on particle acceleration mechanism in thunder cloud electric field using cosmic ray air shower array"
M.Suzuki(M2), M.Ohnishi, Y.Katayose, T.Sako
(Sciety of Atmospheric Electricity of Japan, The 96th meeting, Tokyo university of science, Kagurazaka campus, 9th Jan. 2016、number 51)

When a high energy cosmic rays inject into the thundercloud and generate an air shower , secondary electrons and positrons should be accelerated and decelerated by the influence of the thundercloud electric field. This effect should appear in the total number and the lateral spread distribution of the number of electrons in the air shower that reached the ground. In this presentation, we calculate the air showers in the thundercloud electric field usng an air shower simulator (COSMOS) , and investigated whether the effect of thundercloud electric field can be measured by Tibet-III air shower array.


Publication, PRL (November, 2017)
"Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station"
Phys. Rev. Lett. 119, 181101 (2017)    O. Adriani et al. (CALET Collaboration)

 Abstract: First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X0 and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of ?3.152±0.016 (stat+syst). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.


HIMAC experiment to investigate radio waves generated by the transition radiation process(November, 2017)
In order to investigate the characteristics of the radio waves that should be generated by the transition radiation mechanism, we irradiated carbon 6 MeV/u beam to silicon and polypropylene films and measured radio signal using UHF, VHF antenna.

Presentation at meeting of Japan Phyics Society (September, 2017)
"Measurement of cosmic-ray light nuclei in TeV region with use of the air-shower core detector array"x
M.Kataoka(M2), Y.Katayose, M.Shibata, N.Hotta, K.Kawata, M.Ohnishi,T.Saito, T.Sako, M.Takita (JPS 2017 autumn meeting Utsunomiya university, Mine campus, September 13th, 2017,13aU31-11)

Recently, some experiment groups that observe cosmic rays directly using balloons and satellites have reported a cosmic ray spectrum hardening that weakens the change of spectrum in the TeV region. The cause of this is the influence of nearby supernova remnants and nonlinear acceleration models. In this study, we investigated how to measure light cosmic ray component from several TeVs with high accuracy using grand based air shower experiment by Monte Carlo simulation . We proposed a method to selectively trigger a cosmic ray air shower developed deep into the atmosphere using a high density air shower array called “core detector”

Presentation at meeting of Japan Phyics Society (September, 2017)
"Study of Transition Radiation at Radio Frequencies from Cosmic Ray Showers"
Y.Katayose, K.Aso,T.Sasaki (JPS 2017 autumn meeting Utsunomiya university, Mine campus, September 13th, 2017, 13aU31-10)

In order to clarify the composition of cosmic rays in the ultra-high energy region coming from outside the galaxy, we studied cosmic ray observation methods using radio waves from air shower charged particles. High energy cosmic rays interact with the atmosphere to generate a large amount of secondary particles ("air shower") and reach the ground. When charged particles penetrate the ground from the atmosphere, transition radiation is generated due to the difference between the permittivity and permeability of the atmosphere and the ground. In this presentation, we calculated the distribution of secondary charged particles arriving at the ground using Monte Carlo simulation, and calculated the waveform and intensity of the transition radio wave generated when it collided with the ground.


Honored by the Japan Society for the Promotion of Science. (September, 2017)
Katayose was honored by JSPS that he gave a meaningful review opinion on written examination of special researchers.


Open cumpus (October 5th and 6th, 2017)
We introduced our laboratory to high school students at the university's open campus.
Graduate students and 4th grade students introduced their research contents and demonstrated "Measurement of electrons by hand made Geiger Mueller counters using PET bottle" and "Alfa ray measurement using a mist box with dry ice and alcohol".


Observation experiment of gamma rays accompanied by thundercloud at Mt. Norikura (July - September, 2017)
Aiming to study the mechanism of the gamma ray generation on thundercloud, we performed simultaneous observation experiments of thunder cloud electric field, cosmic ray air shower, MeV gamma ray at Norikura cosmic ray observatory.

Publication, Apj (March, 2017)
"Northern sky Galactic Cosmic Ray Anisotropy between 10-1000 TeV with the Tibet Air Shower Array"
The Astrophysical Journal, Volume 836, Number 2 (2017)    M. Amenomori et al.
"Abstruct" We report the analysis of the 10?1000 TeV large-scale sidereal anisotropy of Galactic cosmic rays (GCRs) with the data collected by the Tibet Air Shower Array from October, 1995 to February, 2010. In this analysis, we improve the energy estimate and extend the declination range down to ?30?. We find that the anisotropy maps above 100 TeV are distinct from that at multi-TeV band. The so-called "tail-in" and "loss-cone" features identified at low energies get less significant and a new component appears at ?100 TeV. The spatial distribution of the GCR intensity with an excess (7.2σ pre-trial, 5.2σ post-trial) and a deficit (?5.8σ pre-trial) are observed in the 300 TeV anisotropy map, in a good agreement with IceCube's results at 400 TeV. Combining the Tibet results in the northern sky with IceCube's results in the southern sky, we establish a full-sky picture of the anisotropy in hundreds of TeV band. We further find that the amplitude of the first order anisotropy increases sharply above ?100 TeV, indicating a new component of the anisotropy. All these results may shed new light on understanding the origin and propagation of GCRs.


Meeting of new joint experimental at Tibet. Nagchu (January 12th, 2017)
Prof. Chen(graduated 2007) and collaborators of Tibet University and Hebei Normal University visited Japan and we had discussion about the new cosmic ray observation plan at Tibet Nagchu.
Prof. Chen Ding (Beijing Astronomical Observatory,) is preparing a huge water Cherenkov type detector of cosmic ray in the Tibetan-Naqchu plateau over 4,800 meters. We are planning to observe high energy gamma rays, galactic electrons and cosmic rays from 100 giga electron volts using this detector. Our laboratory is developing of readout sysytem of the photomultiplier tube which is the main equipment of this observaition.


Presentation at research meeting (October 29th, 2016)
M.Kataoka(M1)"Design Study of Air Shower Core Detector for Measurement of light cosmic ray nucleus in TeV energy region"
K.ASO(B4) "Developmen of event timing module using GPS and NTP server"
  (Tibet ASg meeting、ICRR of Tokyo university)


Publication, Apj Lett. (September, 2016)
"CALET UPPER LIMITS ON X-RAY AND GAMMA-RAY COUNTERPARTS OF GW151226"
The Astrophysical Journal Letters, 829:L20 (5pp), 2016 September ,    Adriani , Y.Katayose, et al.


Presentation at research meeting (Semtember 10th, 2016)x
M. WAKAMATSU(B4)"Development of data acquisition circuit for YAC-III experiment"
(Tibet ASg meeting, ICRR of Tokyo university)


Observation experiment of gamma rays accompanied by thundercloud at Mt. Norikura (August, 2016)
Aiming of study the mechanism of generation of gamma rays by cosmic ray air shower incident on thunder cloud , we conducted simultaneous observation experiment of thundercloud electric field,, cosmic ray air shower and MeV gamma ray at Norikura Cosmic Ray Observatory This is the joint experiment with Kanagawa University, Nihon University, University of Tokyo and Yokoham National university. Unfortunately large-scale lightning did not occur during the observation period of about 2 months.

Presentation at research meeting 「Sub-PeVガンマ線による天体観測から迫るKnee領域宇宙線の起源」(August, 2016)
A research meeting was held to start a new experiment in Bolivia, South America. I reported about the results of the Tibet Asg experiment
Yusaku KATAYOSe "Tibet ASγ experiment ; Study of cosmic ray composition and energy spectrum of TeV-PeV energy egion"
Date: August 8th, (mon.) 11:00-17:45
Cite: ICRR of Tokyo university


Presentation at research meeting (April 16th, 2016)
M. KATAOKA(M1)"Calculation of cosmic-ray spectrum with numerical simulation of galactic cosmic rays transport"
  (Tibet ASg meeting, ICRR of Tokyo university)


Presentation at meeting of Japan Society of Applied Phyics (March 2016)
Kohei MATSUDA(M1) "Simulation study of Single Event Effect in Reverse-type Avalanche Photodiodes(II)", The 63nd JSAP Spring meeting, 2016, 2 Ionizing Radiation,21p-P12-8, Tokyo Institute of Technology, Ookayama campus, 21th march 2016

Graduation research(23th, Feb. 2016)
M.Kataoka(B4)
"Calculation of cosmic-ray spectrum with numerical simulation of galactic cosmic rays transport"
A numerical calculation of cosmic rays transportation was carried out using the "GALPROP"code under the assumptions of a source spectrum shape and a leaky-box model. About the spectrum of proton+helium nuclei, the calculated value was compared with the measurement of TibetASγ-experiment and power of the source spectrum was estimated from the comparison. As a result, we estimated a flux of iron component around the energy of 10^16eV, which is an observation target by the next experiment in Tibet.

T.Ishida(B4)
"Development of a time -digital convert digital convert for Air -shower core detector YAC-III"
We plan to install a new air shower core detector(YAC-Ⅲarray) in Tibet-Ⅲ air shower array to measure heavier component of cosmic rays around the“knee”energy region. For construction of data acquisition system of YAC, we are developing a new electronics circuit to read-out charge signal from PMT of YAC detector. The electronics circuit consists of a charge attenuation circuit, charge-time conversion ASIC (“WDAMP”) and a time-digital converter (TDC). TDC converts a pulse width of WDAMP to digital value. This presentation reports on improvement of TDC and a control system of TDC with VME bus.

H.Yamada(B4)
"A simulation study for measurement of primary cosmic ray spectrum of TeV energy region"

M.Komamura(B4)
"Study of a method to measure extragalactic cosmic-ray composition with air shower core particles"
To study the origin of extragalactic cosmic rays, a new measurement method of air shower particles using water was investigated for both an air shower monte-carlo simulation of cosmic rays with an energy of 10^17eV and a simulation of the passage of particles through water. The high energy secondary particles concentrated around the core area of the air shower and it was found that the energy bundle of more than 10^16eV had an area less than 100 m^2 of center of the air shower. In addition, a proton shower can be distinguished from a shower of iron by the difference in the degree of energy concentration.

M.Suzuki(B4)"Numerical simulation of gamma rays flux generated by cosmic ray incident on a thunder cloud"

Master thesis (17th Feb. 2016)
Koki KAZAMA(M2) "Observational study of gamma-ray radiation associated with a thundercloud electric field"


Presentation at meeting of Sciety of Atmospheric Electricity of Japan(Jan. 2016)
"Observation of cosmic ray and gamma-ray associated with thundercloud at the Norikura-Observatory"
We reported a simultaneous observation result of gamma-rays, cosmic rays and thundercloud electric field. This observation was carried out in Norikura observatory located on 2770m, from August 2015 to September. Unfortunately the huge thunder event did not happen in the observational period of this approximately 20 days. However, we could check detector performance and got valuable data about background event for the future observation.
K. Kazama, Y.Katayose, K.Hibino et al.
(Sciety of Atmospheric Electricity of Japan, The 94th meeting, The university of Electro-Communications, 9th Jan. 2016、number 51)


Publication, APJ(November 2015)
"SEARCH FOR GAMMA RAYS ABOVE 100 TeV FROM THE CRAB NEBULA WITH THE TIBET AIR SHOWER ARRAY AND THE 100m2 MUON DETECTOR"
M.Amenomori, Y.katayose, T.Sako 他, The Astrophysical Journal, Volume 813, Number 2 (2015) 98-102


Gamma ray observation experiment with the thundercloud at the high mountain (September 2015)
For study outbreak mechanism of the gamma ray associated with a thundercloud, we installed 3 crystal scintillation type gamma ray detectors, air shower detectors and electric field meter at NORIKURA cosmic ray observatory. We performed a simultaneous measurement experiment of a thundercloud electric field and gamma ray with the enrgy from several 10 KeV to a few MeV and the air shower for approximately one month.
Upper photographs:Gamma ray detecots(NaI,CsI(Tl),BGO crystal scintillators).The detector was covered by the lead block of the 5cm thickness not to be affected by the environmental radiation.Lower photograph: Gamma ray detecotors and air shower detectors

Presentation at 34th International cosmic ray conference(August 2015)
"Development of a Front-End Electronics for YAC-III detectors of TibetASgamma experimen",M.Amenomori, Y.katayose
We plan to carry out a new experiment(YAC-III) to clarify the flux of the heavy cosmic rays such as the iron atomic nucleuses. We reported development status of an electronics to read-out signal from YAC-III photo-multitubes.


Publication , Advances in Space Research (July 2015)
  
"A balloon experiment using CALET prototype (bCALET-2)" Advances in Space Research 55 (2015) 753-760
Tae Niita , Shoji Torii , Katsuaki Kasahara, Hiroyuki Murakami, Shunsuke Ozawa, Yoshitaka Ueyama, Yosui Akaike, Tadahisa Tamura, Kenji Yoshida, Yusaku Katayose, Yuki Shimizu, Hideyuki Fuke

Presentation at meeting of Japan Phyics Society (March 2015)
Koichi YAMAUCHI(M2) "Study of cosmic ray composition using air shower core array(YAC)",23pDD-10, 23th March , Waseda university

Presentation at meeting of Japan Society of Applied Phyics (March 2015)
Tappei OGITA(M2) "Simulation study of Single Event Effect in Reverse-type Avalanche Photodiodes", The 62nd JSAP Spring meeting, 2015, 2.2Detection systems,12a-P2-11, Tokai university, 11th march 2015

LabTalk (17th Feb. 2015) Our article was introduced at the site of Journal of Physics G: Nuclear and Particle Physics ->HP


Presentation at meeting of Society of Atmospheric Electricity of Japan (Jan. 2015)
Koki KAZAMA(M1)
"Observation of thundercloud-related gamma rays and cosmic rays"
The 92nd meeting, Session 8, ThunderII,52,Chiba university, 10th Jan. 2015


Publication, Astroparticle Physics (December 2014)   
"Performance of the Tibet hybrid experiment (YAC-II+Tibet-III+MD) to measure the energy spectra of the light primary cosmic rays at energies 50-10000 TeV", Astroparticle Physics(accepted)
Left figure:YAC-II array, Right fiure:Expected Proton and Helium spectrum measured by YAC-II experiment. Reconstructed energy spectra of primary proton and helium by ANN method compared with the inputs to the simulation. The figure shows the estimated spectrum compared with the assumed ones under different data sets (E > 1TeV and E > 50 TeV) based on the same QGSJET01c+He-poor model.

Presentation at Tibet ASg meeting (21st December 2014)
Koichi YAMAUCHI(M2)
"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"
To observe the cosmic-ray composition at the knee energy region, Yangbajing Air shower Core (YAC) III experiment is planned in Tibet, China. We developed a YAC-III data acquisition system consisting of a charge-to-time converter module, a time-to-digital converter module, and a CPU module. A wide dynamic range is required to measure the burst size of air shower core from 1 MIP to 106 MIPs (Minimum Ionization Particle) with the YAC detector. The charge-to-time converter module has a linearity from less than 1 pC to more than 1000 pC and the dynamic range of more than three orders of magnitude is achieved.
VME board, Linearity

Koki KAZAMA(M1)"Observation of thundercloud-related gamma rays and cosmic rays"
Mana UENO(B4)"Study of cosmic-gamma-ray selection method by muon lateral distribution measured with Tibet MD"

Publication (November 2014)
"Status and performance of the CALorimetric Electron Telescope (CALET) on the International Space Station",
Nuclear Physics B - Proceedings Supplements Volumes 256-257, November-December 2014, Pages 225-232, O. Adriani, Y.Katayose et al. Abstract


Presentation at Tibet ASg meeting(8th November 2014)
Koichi YAMAUCHI(M2)
"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"

Presentation at Tibet ASg meeting(7th August 2014)
Koi KAZAMA(M1)"Observation of thundercloud-related gamma rays and cosmic rays"
Koichi YAMAUCHI(M2)"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"

Interrim Presentation of master's thesis(4th, 5th August 2014)
Koichi YAMAUCHI(M2)"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"
Tappei OGITA(M2)"Simulation study of Single Event Effect in Reverse-type Avalanche Photodiodes"


Presentations at summere school of "Tenmon Tentai wakate Natsuno gakko"(29th, 30th July 2014)
Koichi YAMAUCHI(M2)"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"
Tappei OGITA(M2)"Simulation study of Single Event Effect in Reverse-type Avalanche Photodiodes"

Grant-in-Aid for Scientific Research (KAKENHI)(April 2014)
Grant-in-Aid for Exploratory Research (April 2014 - March 2016)
Title: "Study of cosmic rays observation method using acoustic wave"
It is well known that a "thermo-acoustic mechanism" is a sound wave that is generated by adiabatic expansion of water when high energy particles lose their energy in water. Some neutrino observations are being tried using such a sound detection method by some experimental groups in Russia and the US. In our study, we investigate the possibility of observation of air-shower core particles generated by high energy cosmic rays, using detection of acoustic signals in water. To inspect a thermo acoustic mechanism, we will perform both a YAG-laser irradiation experiment in water and electron beam irradiation experiment.


Presentation at Tibet ASg meeting(22nd February 2014)   
Yuki AOKI"Study for primary particle selection method using acoustic waves of air-shower particles"
Koki KAZAMA"Development of data acquisition systems for the measurement of gamma rays from thunderstorms"
Yoshiya SHIRATORI"Development of a new VME module for PMT signal read-out for YAC-III project"
Kenta Ohba "Observation level and interaction model dependence of air showers"

Presentation of graduation theses(21st February 2014)   
Yuki AOKI"Study for primary particle selection method using acoustic waves of air-shower particles"
Koki KAZAMA"Development of data acquisition systems for the measurement of gamma rays from thunderstorms"
Yoshiya SHIRATORI"Development of a new VME module for PMT signal read-out for YAC-III project"
Kenta Ohba "Observation level and interaction model dependence of air showers"
Yuki TSURUGASAKI"Study of device structure of reverse type Si-APD by numerical calculation"

Presentation at Tibet ASg meeting(12th October 2013)   
Koichi YAMAUCHI(M1)"Development of data acquisition system of YAC-III experiment to measure iron spectrum around the knee"

Construction of muon detector array in TibetASgamma experiment(September 2013)
TibetASgamma obeservation was reopened after stop of 3 years.
Ion beam experiment at JAEA(4th September 2013)
 To study single event effect in a reverse-type avalanche photodiodes, we performed an ion beam experiment with "TIARA" in Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency

Presentaion at the 33rd International Cosmic ray Conference(July 2013)
Average mass of primary cosmic rays in the knee energy region inferred from Tibet experiment”,
M.Amenomori, Y.katayose et al.
Study of the chemical composition of cosmic rays in the knee region has been made by the Tibet ASg Collaboration using the Tibet-III air shower array and an air-shower-core detector.
Based on the data of all-particle spectrum, proton, and helium spectra obtained by Tibet hybrid experiment, upper and lower limits of the average mass number of primary cosmic rays were estimated in the energy interval between 10^15eV and 10^16eV assuming unmeasured components (all - proton - helium) are any mixture of nuclei between carbon and iron.
The lower limit of with carbon model is approximately 2 and the upper limit with iron model is approximately 3.5 with weak energy dependences. The systematic errors involved in estimating hln Ai due to the primary energy determination or the interaction model dependence in deriving the flux of each nuclear element are discussed and found to be small enough to set the boundary for .
A comparison of our result with recent Icecube data suggests that the primary mass composition is dominated by carbon at 10^15 eV and it tends to be dominated by iron at 10^16 eV.
Energy dependence of primary cosmic-ray composition in terms of hln Ai. The hatched area shows the allowed range inferred from Tibet experiment. The analysis is based on QGSJET+HD model. Other experimental data: ATIC , JACEE, RUNJOB, CASA-MIA, BASJE, GRAPES, KASCADE, EAS-TOP, IceCube/IceTop, CASA-BLANCA, TUNKA, Yakutsk, HiRes.

Synopsis (July 2013)
Our paper was selected as "Synopsis(highlighted with a short summary)" web site
Publication (July 2013)
"Probe of the Solar Magnetic Field Using the “Cosmic-Ray Shadow” of the Sun", Phys. Rev. Lett. 111, 011101 (2013)
M.Amenomori, Y.Katayose et. al., Abstract