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Dive into the research topics where Hirofumi Fujii is active.

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Featured researches published by Hirofumi Fujii.


Nature | 2017

Discovery of a big void in Khufu’s Pyramid by observation of cosmic-ray muons

K. Morishima; Mitsuaki Kuno; Akira Nishio; N. Kitagawa; Yuta Manabe; Masaki Moto; Fumihiko Takasaki; Hirofumi Fujii; Kotaro Satoh; Hideyo Kodama; Kohei Hayashi; Shigeru Odaka; Sébastien Procureur; D. Attié; Simon Bouteille; Denis Calvet; Christopher Filosa; Patrick Magnier; Irakli Mandjavidze; Marc Riallot; Benoit Marini; Pierre Gable; Yoshikatsu Date; Makiko Sugiura; Yasser Elshayeb; Tamer Elnady; Mustapha Ezzy; Emmanuel Guerriero; Vincent Steiger; Nicolas Serikoff

The Great Pyramid, or Khufu’s Pyramid, was built on the Giza plateau in Egypt during the fourth dynasty by the pharaoh Khufu (Cheops), who reigned from 2509 bc to 2483 bc. Despite being one of the oldest and largest monuments on Earth, there is no consensus about how it was built. To understand its internal structure better, we imaged the pyramid using muons, which are by-products of cosmic rays that are only partially absorbed by stone. The resulting cosmic-ray muon radiography allows us to visualize the known and any unknown voids in the pyramid in a non-invasive way. Here we report the discovery of a large void (with a cross-section similar to that of the Grand Gallery and a minimum length of 30u2009metres) situated above the Grand Gallery. This constitutes the first major inner structure found in the Great Pyramid since the nineteenth century. The void, named ScanPyramids’ Big Void, was first observed with nuclear emulsion films installed in the Queen’s chamber, then confirmed with scintillator hodoscopes set up in the same chamber and finally re-confirmed with gas detectors outside the pyramid. This large void has therefore been detected with high confidence by three different muon detection technologies and three independent analyses. These results constitute a breakthrough for the understanding of the internal structure of Khufu’s Pyramid. Although there is currently no information about the intended purpose of this void, these findings show how modern particle physics can shed new light on the world’s archaeological heritage.


Progress of Theoretical and Experimental Physics | 2013

Performance of a remotely located muon radiography system to identify the inner structure of a nuclear plant

Hirofumi Fujii; Kazuhiko Hara; S. Hashimoto; F. Ito; H. Kakuno; Shin-Hong Kim; M. Kochiyama; K. Nagamine; A. Suzuki; Y. Takada; Y. Takahashi; Fumihiko Takasaki; Shinji Yamashita

The performance of a muon radiography system designed to image the inner structure of a nuclear plant located at a distance of 64 m was evaluated. We concluded absence of the fuel in the pressure vessel during the measurement period and succeeded in profiling the fuel material placed in the storage pool. The obtained data also demonstrated the sensitivity of the system to water level changes in the reactor well and the dryer-separator pool. It is expected that the system could reconstruct a 2 m cubic fuel object easily. By operating multiple systems, typically four identical systems, viewing the reactor from different directions simultaneously, detection of a 1 m cubic object should also be achievable within a few month period.


AIP Conference Proceedings (American Institute of Physics); (USA) | 2008

High speed data acquisition system through mainframe at KEK

Hirofumi Fujii; Kasumi Horiuchi; E. Inoue; Hideyo Kodama; M. Nomachi; Y. Yasu

The design of the data acquisition system at KEK is described. A CAMAC List driver for the micro‐VAX, VME/OS‐9 and PC/MS‐DOS operating systems, the data transfer system from front‐end computer to mainframe, and the module by module upgrade of the data transfer system are described. (AIP)


Archive | 1998

Evaluation of Gigabit Ethernet with Java/HORB

Y. Yasu; Hirofumi Fujii; Y. Igarashi; E. Inoue; Hideyo Kodama; A. Manabe; Yoshiyuki Watase; Y. Nagasaka; M. Nomachi; Shinji Hirano; Hideaki Takagi; Kazuyuki Shudo; Tatsuhiro Arai; Luis F. G. Sarmenta; Clark D. Thomborson; Ramona Nicolescu; Myron T. La Duc


Progress of Theoretical and Experimental Physics | 2017

Detection of on-surface objects with an underground radiography detector system using cosmic-ray muons

Hirofumi Fujii; Kazuhiko Hara; Kohei Hayashi; H. Kakuno; Hideyo Kodama; K. Nagamine; Kazuyuki Sato; Kotaro Sato; Shin-Hong Kim; A. Suzuki; Kazuki Takahashi; Fumihiko Takasaki


Archive | 1997

A study of network-based data acquisition system

Y. Yasu; Hirofumi Fujii; E. Inoue; Hideyo Kodama; Yasuaki Sakamoto


Archive | 1997

Event builder system with SBus G-LINK Tx/Rx modules

Y. Nagasaka; Y. Yasu; A. Manabe; O. Sasaki; Hirofumi Fujii; Yoshiyuki Watase; M. Nomachi; M Tairadate


Journal of Cardiothoracic and Vascular Anesthesia | 1996

SBus G-link transmitter and receiver modules for an event builder system

O. Sasaki; Y. Nagasaka; Y. Yasu; A. Manabe; Hirofumi Fujii; Yoshiyuko Watase; M. Nomachi; M Tairadate


Archive | 1994

VMEbus based computer and real-time UNIX as infrastructure of DAQ

Y. Yasu; Hirofumi Fujii; M. Nomachi; Hideyo Kodama; E. Inoue; Youichi Tajima; Yasunori Takeuchi; Yoji Shimizu


Progress of Theoretical and Experimental Physics | 2017

Integrated cosmic muon flux in the zenith angle range

Hirofumi Fujii; Kazuhiko Hara; Kohei Hayashi; H. Kakuno; Hideyo Kodama; K. Nagamine; Kazuyuki Sato; Kotaro Sato; Shin-Hong Kim; A. Suzuki; Kazuki Takahashi; Fumihiko Takasaki

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