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Journal Articles

Neutron angular distribution in ($$gamma$$, n) reactions with linearly polarized $$gamma$$-ray beam generated by laser Compton scattering

Horikawa, Ken*; Miyamoto, Shuji*; Mochizuki, Takayasu*; Amano, So*; Li, D.*; Imasaki, Kazuo*; Izawa, Yasukazu*; Ogata, Kazuyuki*; Chiba, Satoshi*; Hayakawa, Takehito

Physics Letters B, 737, p.109 - 113, 2014/10

 Times Cited Count:11 Percentile:65.49(Astronomy & Astrophysics)

It was predicted in 1950's, the neutron angular distribution in ($$gamma$$, n) reactions with a 100% linearly polarized $$gamma$$-ray beam should be anisotropic and described by a simple function of a + b sin$$^{2}$$$${theta}$$ at 90$$^{circ}$$ on the beam axis but it has not been experimentally confirmed for middle-heavy nuclides over than half a century. We have verified experimentally this angular distribution on $$^{197}$$Au, $$^{127}$$I, and natural Cu using linearly polarized laser Compton scattering $$gamma$$-rays at NewSUBARU.

Journal Articles

Determination of the number of pulsed laser-Compton scattering photons

Kondo, Takeo*; Utsunomiya, Hiroaki*; Akimune, Hidetoshi*; Yamagata, Tamio*; Okamoto, Akiyuki*; Harada, Hideo; Kitatani, Fumito; Shima, Tatsushi*; Horikawa, Ken*; Miyamoto, Shuji*

Nuclear Instruments and Methods in Physics Research A, 659(1), p.462 - 466, 2011/12

 Times Cited Count:22 Percentile:87.25(Instruments & Instrumentation)

We measured pulse-height spectra of 16.7 MeV laser-Compton scattering photons with a 6"$$times$$5" NaI(Tl) detector for blank and three lead materials of 75.8, 50.9, and 25.9% transmissions at the NewSUBARU facility to investigate how the original Poisson distribution of the pulsed photons is modified after passing through thick-target materials. We present a well-prescribed method of determining the number of incident photons within 3.5% accuracy based on the response of the NaI(Tl) detector to the pulsed photon beams.

Journal Articles

Several-MeV $$gamma$$-ray generation at NewSUBARU by laser Compton backscattering

Amano, Sho*; Horikawa, Ken*; Ishihara, Kazuki*; Miyamoto, Shuji*; Hayakawa, Takehito; Shizuma, Toshiyuki; Mochizuki, Takayasu*

Nuclear Instruments and Methods in Physics Research A, 602(2), p.337 - 341, 2009/04

 Times Cited Count:56 Percentile:97.03(Instruments & Instrumentation)

A new laser Compton $$gamma$$ ray source in the energy range of several-MeV was developed using a CO$$_2$$ laser at the NewSUBARU electron storage ring. When the electron energies were 974, 1220 and 1460 MeV, the maximum $$gamma$$ ray energies were measured to be 1.72, 2.72, and 3.91 MeV. The luminosity of the $$gamma$$ rays was 7300 photon/mA/W/s and a flux of 5.8$$times$$10$$^6$$ photon/s was achieved. These performances agreed with calculations. This generation of $$gamma$$ rays is in a no-loss mode for the storage electrons, and the maximum flux was limited only by the power of the laser.

Journal Articles

Half-life of the $$^{164}$$Ho by the ($$gamma$$,$$n$$) reaction from Laser Compton scattering $$gamma$$ rays at the electron storage ring NewSUBARU

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, So*; Horikawa, Ken*; Ishihara, Kazuki*; Mori, Michiaki; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; et al.

Physical Review C, 77(6), p.068801_1 - 068801_4, 2008/06

 Times Cited Count:11 Percentile:60.8(Physics, Nuclear)

no abstracts in English

Journal Articles

Absolute calibration of imaging plate for GeV electrons

Nakanii, Nobuhiko*; Kondo, Kiminori; Yabuuchi, Toshinori*; Tsuji, Kazuki*; Tanaka, Kazuo*; Suzuki, Shinsuke*; Asaka, Takao*; Yanagida, Kenichi*; Hanaki, Hirofumi*; Kobayashi, Takashi*; et al.

Review of Scientific Instruments, 79(6), p.166102_1 - 066102_3, 2008/06

An imaging plate has been used as a useful detector of energetic electrons in laser electron acceleration and laser fusion studies. The absolute sensitivity of an imaging plate was calibrated at 1 GeV electron energy using the injector Linac of SPring-8. The sensitivity curve obtained up to 100 MeV in a previous study was extended successfully to GeV range.

Journal Articles

Half-life of $$^{184}$$Re populated by the $$(gamma,n)$$ reaction from laser Compton scattering $$gamma$$ rays at the electron storage ring NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

Physical Review C, 74(6), p.065802_1 - 065802_5, 2006/12

 Times Cited Count:23 Percentile:79.56(Physics, Nuclear)

We report a half-life of the ground state of $$^{184}$$Re populated by the $$^{185}$$Re$$(gamma,n)$$$$^{184}$$Re reaction with the laser Compton scattering $$gamma$$-rays generated through relativistic engineering. The $$gamma$$-rays are provided at the electron storage ring NewSUBARU. The previous experiment using deuteron-induced reactions has yielded a recommended half-life of the 3$$^-$$ ground state of $$^{184}$$Re to be 38.0 $$pm$$ 0.5 d, including a possible contribution from the 8$$^{+}$$ isomer ($$T_{1/2}$$ = 169 $$pm$$ 8 d) of $$^{184}$$Re since the presence of the isomer was not known at that time. In contrast, the $$(gamma,n)$$ reaction has an advantage to selectively populate the ground state because this reaction does not bring large angular momentum. The measured half-life of 35.4 $$pm$$ 0.7 d is shorter than the previous half-life by about 7%. This difference is crucial for applications using the activation method.

Oral presentation

Nuclear photoreaction on Re isotopes by Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

no journal, , 

no abstracts in English

Oral presentation

Half-life of $$^{184}$$Re populated by photodisintegration reaction with Laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

no journal, , 

no abstracts in English

Oral presentation

Cross section measurements of photo-nuclear reactions for light nuclei using laser Compton scattered $$gamma$$ rays

Shizuma, Toshiyuki; Kawase, Keigo; Hayakawa, Takehito; Miyamoto, Shuji*; Horikawa, Ken*; Fujiwara, Mamoru

no journal, , 

no abstracts in English

Oral presentation

Decay and population of Ho-164 using photo-induced reactions by laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, So*; Horikawa, Ken*; Ishihara, Kazuki*; Mori, Michiaki; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; et al.

no journal, , 

no abstracts in English

Oral presentation

Measurements of photo-nuclear reaction cross sections for $$^{35}$$Cl and $$^{39}$$K using laser Compton scattering photons

Shizuma, Toshiyuki; Hayakawa, Takehito; Kawase, Keigo; Fujiwara, Mamoru; Miyamoto, Shuji*; Horikawa, Ken*

no journal, , 

no abstracts in English

Oral presentation

The Tardigrade ${it Ramazzottius varieornatus}$; A Model for astrobiological studies

Horikawa, Daiki*; Kunieda, Takekazu*; Abe, Wataru*; Koshikawa, Shigeyuki*; Nakahara, Yuichi*; Watanabe, Masahiko*; Iwata, Kenichi*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Higashi, Seigo*; et al.

no journal, , 

We report the first successful rearing of the herbivorous tardigrade, ${it Ramazzottius varieornatus}$, by supplying a green alga ${it Chlorella vulgaris}$ as a food. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle, from eggs, to juveniles, and to adults. Reared adults, while in an anhydrobiotic state, were tolerant to temperatures -196$$^{circ}$$C and 100$$^{circ}$$C. Furthermore, they were shown to be tolerant to the exposure to 99.8% acetonitrile, 1 GPa of hydrostatic pressure, or 5000 Gy of He ion radiation. We will report the details of these results, along with the description of their life history. Due to the observed tolerance to such extreme environmental conditions, we propose R. varieornatus to be included as a suitable model for astrobiological studies of multicellular organisms.

Oral presentation

Half-life measurements of neutron-deficient isotopes using laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, Sho*; Horikawa, Ken*; Hayashi, Yukio; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; Chiba, Satoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Nuclear resonance fluorescence measurements on $$^{40}$$Ca using laser Compton scattering $$gamma$$ rays

Shizuma, Toshiyuki; Hayakawa, Takehito; Kawase, Keigo; Miyamoto, Shuji*; Horikawa, Ken*; Fujiwara, Mamoru

no journal, , 

no abstracts in English

Oral presentation

Angular distribution of neutron produced by a ($$gamma$$, n) reaction with linear polarized laser Compton scattering $$gamma$$-ray beam

Hayakawa, Takehito; Horikawa, Ken*; Mochizuki, Takayasu*; Miyamoto, Shuji*; Amano, So*; Izawa, Yasukazu*; Imasaki, Kazuo*; Chiba, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Nuclear resonance fluorescence experiments on doubly closed nucleus Ca-40 by using laser Compton $$gamma$$ rays

Shizuma, Toshiyuki; Hayakawa, Takehito; Utsuno, Yutaka; Miyamoto, Shuji*; Horikawa, Ken*

no journal, , 

Photon scattering experiments on the doubly closed nucleus Ca-40 were performed using a highly polarized, mono-energetic photon beam from laser Compton scattering. An excited state at an excitation energy of 10.3 MeV based on magnetic dipole excitation was observed from the measurement of scattered radiation with a high pure Ge detector. In this talk, we will report on results of the photon scattering experiment on Ca-40 and calculations of magnetic dipole strengths using large scale shell model.

Oral presentation

Neutron angular distribution for ($$gamma$$, n) reactions with linear polarized photons

Hayakawa, Takehito; Miyamoto, Shuji*; Horikawa, Ken*; Mochizuki, Takayasu*; Amano, So*; Li, D.*; Imasaki, Kazuo*; Izawa, Yasukazu*; Chiba, Satoshi*; Ogata, Kazuyuki*

no journal, , 

It was predicted in 1950's that the neutron angular distribution in ($$gamma$$,n) reactions with a 100% linearly polarized $$gamma$$-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a + b$$cdot$$cos($${2}{phi}$$) at polar angle $$theta$$ = 90$$^{circ}$$, where $$phi$$ is the azimuthal angle,but it has not been experimentally confirmed over half a century. We have verified experimentally this angular distribution on three targets using linearly polarized laser Compton scattering $$gamma$$-rays at NewSUBARU.

Oral presentation

Verification of angular distribution of ($$gamma$$, n) reaction with linear polarized $$gamma$$-rays predicted theoretically half a century ago

Hayakawa, Takehito; Horikawa, Ken*; Miyamoto, Shuji*; Mochizuki, Takayasu*; Amano, So*; Li, D.*; Imasaki, Kazuo*; Izawa, Yasukazu*; Ogata, Kazuyuki*; Chiba, Satoshi*

no journal, , 

In 1950's, Agodi predicted that the neutron angular distribution in ($$gamma$$, n) reactions with a 100% linearly polarized $$gamma$$-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a + b$$cdot$$cos($${2}{phi}$$)at polar angle $$theta$$=90$$^{circ}$$, where $$phi$$ is the azimuthal angle, but it has not been experimentally confirmed over half a century. The work by Agodi had been forgotten after 1970's. We have verified experimentally this angular distribution on three targets using linearly polarized laser Compton scattering $$gamma$$-rays at NewSUBARU for the first time.

Oral presentation

Laser Compton scattering $$gamma$$-ray experiments for supernova neutrino process

Hayakawa, Takehito; Miyamoto, Shuji*; Mochizuki, Takayasu*; Horikawa, Ken*; Amano, So*; Li, D.*; Imasaki, Kazuo*; Izawa, Yasukazu*; Ogata, Kazuyuki*; Chiba, Satoshi*

no journal, , 

The M1 strength in atomic nuclei is important for estimation of neutrino-nucleus interactions in supernovae. We have proposed a method using ($$gamma$$, n) reactions with linear polarized laser Compton scattering (LCS) $$gamma$$-rays to measure the M1 strength and verified a theoretical prediction for the first time.

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