176 citations · 574 across the 22 of their papers we have counts for
22 papers
High-sensitivity low-noise photodetector using large-area silicon photomultiplier
Takahiko Masuda, Ayami Hiramoto, Daniel G. Ang +9
The application of silicon photomultiplier (SiPM) technology for weak-light detection at a single photon level has expanded thanks to its better photon detection efficiency in comp…
Estimation of radiative half-life of Th by half-life measurement of other nuclear excited states in Th
Y. Shigekawa, A. Yamaguchi, K. Suzuki +8
We perform coincidence measurements between particles and rays from a U source to determine the half-lives of the excited state in a Th nucleus. We first pr…
Suppression of the optical crosstalk in a multi-channel silicon photomultiplier array
Takahiko Masuda, Daniel G. Ang, Nicholas R. Hutzler +8
We propose and study a method of optical crosstalk suppression for silicon photomultipliers (SiPMs) using optical filters. We demonstrate that attaching absorptive visible bandpass…
Study of the Decay at the J-PARC KOTO Experiment
KOTO Collaboration, J. K. Ahn, B. Beckford +68
The rare decay was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of $( 7.20 \p…
Absolute X-ray energy measurement using a high-accuracy angle encoder
Takahiko Masuda, Tsukasa Watanabe, Kjeld Beeks +16
This paper presents an absolute X-ray photon energy measurement method that uses a Bond diffractometer. The proposed system enables the prompt and rapid in-situ measurement of phot…
Development of a measurement system enabling the reconstruction of gamma-ray time spectra by simultaneous recording of energy and time information
Hiroyuki Tajima, Shinji Kitao, Ryo Masuda +4
We developed a measurement system that enables the reconstruction of γ-ray time spectra in cascade decay schemes. As this system records all the time and energy information of γ-ra…
X-ray pumping of the Th-229 nuclear clock isomer
Takahiko Masuda, Akihiro Yoshimi, Akira Fujieda +27
Thorium-229 is a unique case in nuclear physics: it presents a metastable first excited state Th-229m, just a few electronvolts above the nuclear ground state. This so-called isome…
Geometry-dependent spectra and coherent-transient measurement of nearly degenerate four-wave mixing using two-photon resonance
Hideaki Hara, Yuki Miyamoto, Takahiro Hiraki +7
We study nearly degenerate four-wave mixing using a two-photon-allowed vibrational transition of parahydrogen. A signal photon is generated by a trigger photon and coherence among…
Search for and Decays at the J-PARC KOTO Experiment
KOTO Collaboration, J. K. Ahn, B. Beckford +67
A search for the rare decay was performed. With the data collected in 2015, corresponding to protons on target, a single event se…
Energy response of X-rays under high flux conditions using a thin APD for the energy range of 6-33 keV
T. Masuda, T. Hiraki, H. Kaino +10
This paper reports on the demonstration of a high-rate energy measurement technique using a thin depletion layer silicon avalanche photodiode (Si-APD). A dedicated amplitude-to-tim…
Coherent two-photon emission from hydrogen molecules excited by counter-propagating laser pulses
Takahiro Hiraki, Hideaki Hara, Yuki Miyamoto +7
We observed two-photon emission signals from the first vibrationally excited state of parahydrogen gas excited coherently by counter-propagating laser pulses. A single narrow-linew…
Nuclear resonant scattering experiment with fast time response: new scheme for observation of Th radiative decay
A. Yoshimi, H. Hara, T. Hiraki +24
Nuclear resonant excitation of the 29.19-keV level in Th with high-brilliance synchrotron- radiation and detection of its decay signal, are proposed with the aim of populat…
Fast X-ray detector system with simultaneous measurement of timing and energy for a single photon
T. Masuda, S. Okubo, H. Hara +12
We developed a fast X-ray detector system for nuclear resonant scattering (NRS) experiments. Our system employs silicon avalanche photo-diode (Si-APD) as a fast X-ray sensor. The s…
Vibrational two-photon emission from coherently excited solid parahydrogen
Yuki Miyamoto, Hideaki Hara, Takahiko Masuda +5
We report observation of two-photon emission from coherently excited vibrational state of solid parahydrogen, known as one of quantum solids. The coherent state between the ground…
A new search for the and decays
J. K. Ahn, K. Y. Baek, S. Banno +87
We searched for the -violating rare decay of neutral kaon, , in data from the first 100 hours of physics running in 2013 of the J-PARC KOTO experimen…
Development of a low-mass and high-efficiency charged particle detector
D. Naito, Y. Maeda, N. Kawasaki +8
We developed a low-mass and high-efficiency charged particle detector for an experimental study of the rare decay . The detector is important to suppres…
Injection seeded tunable mid-infrared pulses by difference frequency mixing
Yuki Miyamoto, Hideaki Hara, Takahiko Masuda +3
We report on the generation of nanosecond mid-infrared pulses having frequency tunability, a narrow linewidth, and a high pulse energy. These pulses are obtained by frequency mixin…
Long-lived neutral-kaon flux measurement for the KOTO experiment
T. Masuda, J. K. Ahn, S. Banno +54
The KOTO ( at Tokai) experiment aims to observe the CP-violating rare decay by using a long-lived neutral-kaon beam produced by the 30 GeV proton…
Externally triggered coherent two-photon emission from hydrogen molecules
Yuki Miyamoto, Hideaki Hara, Takahiko Masuda +6
We report coherent enhancement of two-photon emission from the excited vibrational state of molecular hydrogen triggered by irradiating mid-infrared pulses externally. We previousl…
An aerogel Cherenkov detector for multi-GeV photon detection with low sensitivity to neutrons
Y. Maeda, N. Kawasaki, T. Masuda +10
We describe a novel photon detector which operates under an intense flux of neutrons. It is composed of lead-aerogel sandwich counter modules. Its salient features are high photon…
Photon-Veto Counters at the Outer Edge of the Endcap Calorimeter for the KOTO Experiment
T. Matsumura, T. Shinkawa, H. Yokota +17
The Outer-Edge Veto (OEV) counter subsystem for extra-photon detection from the backgrounds for the? decay is located at the outer edge of the endcap Cs…
Observation of coherent two-photon emission from the first vibrationally-excited state of hydrogen molecules
Yuki Miyamoto, Hideaki Hara, Susumu Kuma +10
In this paper, we describe an experiment which was conducted to explore the macro-coherent amplification mechanism using a two-photon emission process from the first vibrationally-…