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論文

Evaluation of gamma-ray strength function based on measured gamma-ray pulse-height spectra in time-of-flight neutron capture experiments

岩本 信之; 中村 詔司; 木村 敦; 片渕 竜也*; Rovira, G.*; 原 かおる*; 岩本 修

EPJ Web of Conferences, 239, p.17016_1 - 17016_4, 2020/09

https://doi.org/10.1051/epjconf/202023917016
 被引用回数：0 パーセンタイル：0.1(Nuclear Science & Technology)

Gamma-ray strength function (GSF) as well as nuclear level density is important ingredients to calculate neutron capture cross sections, since it gives energy-dependent transition strength of gamma-rays from a capture state and directly relates to spectrum of emitted gamma-rays. Therefore, the improvement of GSF is essential to enhance the reliability of neutron capture cross sections. The shape of GSF has been determined by experiments of neutron capture reactions, (p,p') reactions and nuclear resonance fluorescence. In addition, the use of the information of gamma-ray spectrum (i.e., pulse-height (PH) spectrum) measured by time-of-flight experiments is effective to evaluate the GSF. A lot of PH spectra have been measured by the Ge and NaI(Tl) detectors of the ANNRI installed at the Material and Life Science Experimental Facility in J-PARC. However, those spectra have not been actively used to extract the information of GSF so far. In the present study, we measured the PH spectrum of gold by using the NaI(Tl) detectors in ANNRI and used it for the evaluation of GSF. The gamma-ray spectrum for gold was calculated by a nuclear reaction model code CCONE. The obtained gamma-ray spectrum was applied to the Monte Carlo particle transport simulation code PHITS to derive PH spectrum comparable with the measured data. After this evaluation, we obtained GSF, reasonably explained the measured PH spectrum.

論文

Manipulation of saturation magnetization and perpendicular magnetic anisotropy in epitaxial Co$$_{x}$$Mn$$_{4-x}$$N films with ferrimagnetic compensation

伊藤 啓太*; 安富 陽子*; Zhu, S.*; Nurmamat, M.*; 田原 昌樹*; 都甲 薫*; 秋山 了太*; 竹田 幸治; 斎藤 祐児; 小口 多美夫*; et al.

Physical Review B, 101(10), p.104401_1 - 104401_8, 2020/03

https://doi.org/10.1103/PhysRevB.101.104401
 被引用回数：17 パーセンタイル：75.65(Materials Science, Multidisciplinary)

Spintronics devices utilizing a magnetic domain wall motion have attracted increasing attention, and ferrimagentic materials with almost compensated magnetic moments are highly required to realize the fast magnetic domain wall motion. Here, we report a key function for this purpose in anti-perovskite Co$$_{x}$$Mn$$_{4-x}$$N films. Perpendicular magnetization emerges for $$0.8 leq x$$, and the saturation magnetization reaches a minimum value at $$x = 0.8$$.

論文

Measurement of local temperature around the impact points of fast ions under grazing incidence

古株 弘樹*; Yoon, S.*; Lee, H.*; 中嶋 薫*; 松田 誠; 左高 正雄*; 辻本 将彦*; Toulemonde, M.*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 460, p.34 - 37, 2019/12

https://doi.org/10.1016/j.nimb.2019.01.006
 被引用回数：0 パーセンタイル：0.02(Instruments & Instrumentation)

Gold and platinum nanoparticles of few-nm size were deposited on amorphous silicon nitride (a-SiN) films. These samples were irradiated with 380 MeV Au ions at grazing incident angles ($$theta$$$$_{i}$$=2$$^{circ}$$-5$$^{circ}$$) to a fluence of ~1$$times$$10$$^{10}$$ ions/cm$$^{2}$$. The irradiated samples were observed using transmission electron microscopy (TEM). Ion tracks were clearly observed as long bright lines. Nanoparticles were found to be desorbed from long and narrow regions along the ion tracks. The surface temperature at the thermal spike produced by the ion impact was evaluated from the observed nanoparticle desorption. The observed temperature distribution is qualitatively explained by a one-dimensional two temperature model (1D-TTM) although there are some discrepancies which may be attributed to the surface effects which are not taken into account in 1D-TTM.

論文

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

https://doi.org/10.3390/qubs1030009

J-PARC物質・生命科学実験施設の中性子実験装置についてのレビューである。物質・生命科学実験施設には23の中性子ビームポートがあり21台の装置が設置されている。それらは、J-PARCの高性能な中性子源と最新の技術を組み合わせた世界屈指の実験装置群である。このレビューでは、装置性能や典型的な成果等について概観する。

論文

Temperature of thermal spikes induced by swift heavy ions

松崎 勝太*; 林 宏明*; 中嶋 薫*; 松田 誠; 左高 正雄*; 辻本 将彦*; Toulemonde, M.*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 406(Part B), p.456 - 459, 2017/09

https://doi.org/10.1016/j.nimb.2016.12.019
 被引用回数：4 パーセンタイル：36.71(Instruments & Instrumentation)

Few-nm sized gold, platinum and palladium nanoparticles were deposited on amorphous silicon nitride films. These films were irradiated with 420 MeV Au and 100 MeV Xe ions. Temperature distributions of thermal spikes produced by these ions were evaluated by observing desorption of the nanoparticles from the target surfaces upon ion impact. It was found that the temperature of the thermal spike produced by 420 MeV Au is higher than 100 MeV Xe. The observed temperature of the thermal spike at the entrance surface is slightly lower than that at the exit surface both for 420 MeV Au and 100 MeV Xe ions. These results can be well explained by the inelastic thermal spike model.

論文

Tracing temperature in a nanometer size region in a picosecond time period

中嶋 薫*; 北山 巧*; 林 宏明*; 松田 誠; 左高 正雄*; 辻本 将彦*; Toulemonde, M.*; Bouffard, S.*; 木村 健二*

Scientific Reports (Internet), 5, p.13363_1 - 13363_8, 2015/08

https://doi.org/10.1038/srep13363
 被引用回数：5 パーセンタイル：40.93(Multidisciplinary Sciences)

Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

論文

Temperature of thermal spikes in amorphous silicon nitride films produced by 1.11 MeV C$$_{60}^{3+}$$ impacts

北山 巧*; 中嶋 薫*; 鈴木 基史*; 鳴海 一雅; 齋藤 勇一; 松田 誠; 左高 正雄*; 辻本 将彦*; 磯田 正二*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 354, p.183 - 186, 2015/07

https://doi.org/10.1016/j.nimb.2014.11.002
 被引用回数：2 パーセンタイル：17.52(Instruments & Instrumentation)

According to an inelastic-thermal-spike (i-TS) model, which is regarded as the most promising among several models proposed to explain the formation of an ion track, a part of the energy deposited to electrons in a solid by a swift heavy ion is gradually transferred to target atoms via electron-phonon coupling. The temperature of target atoms rises along the ion path and consequently an ion track is formed when the temperature exceeds the melting point. Therefore, the temperature of target atoms along the ion path is regarded as a key parameter for the i-TS model; however, such a spatiotemporally-localized temperature is difficult to measure because the processes involved occur in a very short period ($$<$$ 10$$^{-10}$$ s) and in a very localized area. In this study, the temperature of target atoms along the ion path is estimated experimentally with transmission-electron-microscope (TEM) observation of desorption of Au nanoclusters (the melting point $$sim$$1300 K) on an amorphous Si$$_{3}$$N$$_{4}$$ thin film under 1.1-MeV C$$_{60}^{3+}$$-ion irradiation to the fluence of $$sim$$5$$times$$10$$^{10}$$ ions/cm$$^{2}$$. TEM images show that Au nanoclusters, deposited at the areal density of 1.16$$times$$10$$^{12}$$ particles/cm$$^{2}$$, disappear in a surface area with a diameter of $$sim$$20 nm around each ion track, whose diameter is $$sim$$4 nm, after irradiation. This indicates that the temperature at the film surface rises locally to at least 1300 K by the ion bombardment.

論文

Local electronic states of Fe$$_{4}$$N films revealed by X-ray absorption spectroscopy and X-ray magnetic circular dichroism

伊藤 啓太*; 都甲 薫*; 竹田 幸治; 斎藤 祐児; 小口 多美夫*; 末益 崇*; 木村 昭夫*

Journal of Applied Physics, 117(19), p.193906_1 - 193906_6, 2015/05

https://doi.org/10.1063/1.4921431
 被引用回数：14 パーセンタイル：52.11(Physics, Applied)

We performed XAS and XMCD measurements at Fe L$$_{2,3}$$ and N K-edges for Fe$$_{4}$$N epitaxial films grown by MBE. We compared experimental XAS and XMCD spectra with those simulated by a combination of a first-principles calculation and Fermi's golden rule. We revealed that the shoulders observed at Fe L$$_{2,3}$$-edges in the XAS and XMCD spectra were due to the electric dipole transition from the Fe 2p core-level to the hybridization state generated by $$sigma$$$$^{ast}$$ anti-bonding between the orbitals of N 2p at the body-centered site and Fe 3d on the face-centered (II) sites. Thus, the observed shoulders were attributed to the local electronic structure of Fe atoms at II sites. As to the N K-edge, the line shape of the obtained spectra was explained by the dipole transition from the N 1s core-level to the hybridization state formed by $$pi$$$$^{ast}$$ and $$sigma$$$$^{ast}$$ anti-bondings between the Fe 3d and N 2p orbitals.

論文

Misassigned neutron resonances of $$^{142}$$Nd and stellar neutron capture cross sections

片渕 竜也*; 松橋 泰平*; 寺田 和司; 井頭 政之*; 水本 元治*; 廣瀬 健太郎; 木村 敦; 岩本 信之; 原 かおる*; 原田 秀郎; et al.

Physical Review C, 91(3), p.037603_1 - 037603_5, 2015/03

https://doi.org/10.1103/PhysRevC.91.037603
 被引用回数：8 パーセンタイル：50.48(Physics, Nuclear)

Time-of-flight spectra of the neutron capture events of $$^{142}$$Nd were measured using a spallation neutron source at the Japan Proton Accelerator Research Complex. The first six resonances of $$^{142}$$Nd reported in a previous work were not observed. The experimental results and cross-search of resonance energies in nuclear data libraries suggested that resonances of impurity nuclide $$^{141}$$Pr have been mistakenly assigned as $$^{142}$$Nd in the previous experiment. To investigate the impact of non-existence of the resonances to the s-process nucleosynthesis model, the Maxwellian averaged neutron capture cross sections with and without the misassigned resonances were compared.

論文

Response function for the measurement of (n,$$gamma$$) reactions with the ANNRI-Cluster Ge detectors at J-PARC

原 かおる; 後神 進史*; 原田 秀郎; 廣瀬 健太郎; 木村 敦; 金 政浩*; 北谷 文人; 小泉 光生; 中村 詔司; 藤 暢輔; et al.

JAEA-Conf 2014-002, p.88 - 92, 2015/02

https://doi.org/10.11484/jaea-conf-2014-002

Recently, neutron shields of a large Ge detector array at the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) in the Japan Proton Accelerator Research Complex (J-PARC) were modified to suppress the background from boron rubber sheets to enriched $$^{6}$$LiF tiles. For the new experimental set-up, efficiencies and response functions of the cluster Ge detectors with the BGO anti-coincidence detectors were measured with $$gamma$$-rays from standard sources and prompt $$gamma$$-rays from the $$^{28}$$Si(n,$$gamma$$) and $$^{35}$$Cl(n,$$gamma$$) reactions. The simulation parameters were adjusted with the EGS5 code so as to reproduce the data set of efficiencies and response functions. Based on this information, a pulse height weighting function will be deduced in the energy range of 0.1-10 MeV.

論文

Synergistic effect of combining two nondestructive analytical methods for multielemental analysis

藤 暢輔; 海老原 充*; 木村 敦; 中村 詔司; 原田 秀郎; 原 かおる*; 小泉 光生; 北谷 文人; 古高 和禎

Analytical Chemistry, 86(24), p.12030 - 12036, 2014/12

https://doi.org/10.1021/ac502632w
 被引用回数：19 パーセンタイル：56.95(Chemistry, Analytical)

非破壊分析法は科学研究の多くの分野において必要不可欠のツールとして用いられてきた。即発$$gamma$$線分析は$$gamma$$線のエネルギーを解析することにより元素分析を行う手法であり、共鳴捕獲元素分析は中性子の共鳴エネルギーを使う手法である。どちらの手法も試料を中性子に照射して$$gamma$$線を検出する手法であるが、これまで同時に用いられることはなかった。我々は強力なパルス中性子ビームを用いることによって、2つの手法を組み合わせた手法を初めて開発した。開発した手法は、一度に両方の手法からの測定結果を得ることができるだけでなく、この融合による相乗効果も得られる。つまり、どちらの手法でも分析が困難である試料を分析することができる。本論文では開発した手法をCo, Au, Agなどを含む混合試料に適用し、従来法のスペクトルにある不可分のピークから信頼性の高いデータが得られることを証明している。

論文

Sputtering of SiN films by 540 keV C$$_{60}$$$$^{2+}$$ ions observed using high-resolution Rutherford backscattering spectroscopy

中嶋 薫*; 森田 陽亮*; 北山 巧*; 鈴木 基史*; 鳴海 一雅; 齋藤 勇一; 辻本 将彦*; 磯田 正二*; 藤居 義和*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 332, p.117 - 121, 2014/08

https://doi.org/10.1016/j.nimb.2014.02.042
 被引用回数：7 パーセンタイル：48.18(Instruments & Instrumentation)

Our previous observation that an impact of sub-MeV C$$_{60}$$ ion makes an ion track in a thin amorphous silicon nitride (a-SiN) film suggests emission of thousands of atoms from the cylindrical region. Sputtering yields of a-SiN films by C$$_{60}$$ ions were evaluated in order to confirm this observation. A-SiN films deposited on Si(001) were irradiated with 540-keV C$$_{60}$$$$^{2+}$$ ions at fluences from 2.5$$times$$10$$^{11}$$ to 1$$times$$10$$^{14}$$ ions/cm$$^{2}$$. The compositional depth profiles of the irradiated samples were measured with high-resolution Rutherford backscattering spectroscopy, and the sputtering yields were estimated at 3900 $$pm$$ 500 N atoms/ion and 1500 $$pm$$ 1000 Si atoms/ion. The sputtering yield of N was two orders of magnitude larger than the elastic sputtering yield by the SRIM code or than the measured electronic sputtering yield of a-SiN by 50-MeV Cu ions previously reported. Such a large sputtering yield cannot be explained either by the elastic sputtering or by the electronic sputtering. However, an estimation of the synergistic effect based on the inelastic thermal spike model roughly explains the observed large sputtering yield, indicating that the synergistic effect of the nuclear and electronic stopping powers plays an important role.

論文

X-ray magnetic circular dichroism for Co$$_{x}$$Fe$$_{4-x}$$N (x = 0, 3, 4) films grown by molecular beam epitaxy

伊藤 啓太*; 佐内 辰徳*; 安富 陽子*; Zhu, S.-Y.*; 都甲 薫*; 竹田 幸治; 斎藤 祐児; 木村 昭夫*; 末益 崇*

Journal of Applied Physics, 115(17), p.17C712_1 - 17C712_3, 2014/05

https://doi.org/10.1063/1.4862517
 被引用回数：18 パーセンタイル：60.12(Physics, Applied)

We evaluated orbital ($$m_{rm orb}$$) and spin magnetic moments ($$m_{rm spin}$$) of Co$$_{x}$$Fe$$_{4-x}$$N (x = 0, 3, 4) epitaxial thin films grown by molecular beam epitaxy using X-ray magnetic circular dichroism, and discussed the dependence of these values on x. Site-averaged $$m_{rm spin}$$ value of Fe atoms was deduced to be 1.91 $$mu$$$$_{B}$$ per atom, and that of Co atoms to be 1.47 $$mu$$$$_{B}$$ per atom in Co$$_{3}$$FeN at 300 K. These values are close to 1.87 $$mu$$$$_{B}$$ per Fe atom in Fe$$_{4}$$N and 1.43 $$mu$$$$_{B}$$ per Co atom in Co$$_{4}$$N, respectively. This result implies that the Fe and Co atoms in the Co$$_{3}$$FeN films were located both at corner and face-centered sites in the anti-perovskite lattice. Spin magnetic moments per unit cell were decreased linearly with increasing x in Co$$_{x}$$Fe$$_{4-x}$$N. This tendency is in good agreement with theory predicted by the first-principle calculation.

論文

Measurements of neutron capture cross sections of $$^{112}$$Sn and $$^{118}$$Sn with J-PARC/MLF/ANNRI

木村 敦; 廣瀬 健太郎; 中村 詔司; 原田 秀郎; 原 かおる; 堀 順一*; 井頭 政之*; 加美山 隆*; 片渕 竜也*; 木野 幸一*; et al.

Nuclear Data Sheets, 119, p.150 - 153, 2014/05

https://doi.org/10.1016/j.nds.2014.08.042
 被引用回数：5 パーセンタイル：37.93(Physics, Nuclear)

The neutron-capture cross sections of $$^{112}$$Sn and $$^{118}$$Sn were measured by the time-of-flight method in the energy range from 10 meV to 2 keV with an array of germanium detectors in ANNRI at J-PARC. The preliminary results of the neutron-capture cross sections for $$^{112}$$Sn and $$^{118}$$Sn were obtained by normalizing the relative cross sections to the thermal cross section measured by Krane and to the evaluated value of JENDL-4.0 at the 47.05-eV resonance, respectively. Twelve new resonances for $$^{112}$$Sn were observed, whereas the 21.02-, 40.38- and 166-eV resonances for $$^{112}$$Sn and the 289-eV resonance for $$^{118}$$Sn which are listed on JENDL-4.0 and/or ENDF/B VII.1 were not observed. The prompt $$gamma$$-ray distributions gated at the $$^{112}$$Sn and $$^{118}$$Sn resonances were obtained. Twenty-three new prompt $$gamma$$-ray emissions were observed in the $$^{112}$$Sn (n,$$gamma$$) reactions.

論文

Cross section measurements of the radioactive $$^{107}$$Pd and stable $$^{105,108}$$Pd nuclei at J-PARC/MLF/ANNRI

中村 詔司; 木村 敦; 北谷 文人; 太田 雅之; 古高 和禎; 後神 進史*; 原 かおる; 原田 秀郎; 廣瀬 健太郎; 金 政浩*; et al.

Nuclear Data Sheets, 119, p.143 - 146, 2014/05

https://doi.org/10.1016/j.nds.2014.08.040
 被引用回数：10 パーセンタイル：57.1(Physics, Nuclear)

長寿命放射性核種$$^{107}$$Pd、及び不純物として含まれている安定核種$$^{105,108}$$Pdの中性子捕獲断面積を測定した。J-PARCの物質・生命科学実験施設(MLF)のBL04に整備された中性子核反応実験装置(ANNRI)を用いて、飛行時間法により熱領域から300eVの中性子エネルギーに対して、中性子捕獲断面積を測定した。報告されていた幾つかの共鳴が、$$^{107}$$Pdに起因しないことなど、共鳴に関する新たな知見が得られた。

論文

Capture cross-section measurement of $$^{241}$$Am(n,$$gamma$$) at J-PARC/MLF/ANNRI

原田 秀郎; 太田 雅之; 木村 敦; 古高 和禎; 廣瀬 健太郎; 原 かおる; 金 政浩*; 北谷 文人; 小泉 光生; 中村 詔司; et al.

Nuclear Data Sheets, 119, p.61 - 64, 2014/05

https://doi.org/10.1016/j.nds.2014.08.019
 被引用回数：19 パーセンタイル：75.91(Physics, Nuclear)

Accurate determination of the neutron capture cross sections of radioactive nuclei is required in the fields of nuclear waste transmutation study and also nuclear astrophysics. The accurate neutron-nucleus reaction measurement instrument (ANNRI), which was installed in the materials and life science experimental facility (MLF) at the J-PARC, is expected to satisfy these demands. The capture cross section of $$^{241}$$Am was measured using a high efficiency Ge spectrometer installed in the ANNRI. By taking advantage of its high $$gamma$$-ray energy resolution, background components were precisely subtracted. The capture cross section of $$^{241}$$Am was deduced for a neutron energy region between 0.01 and 20 eV. The obtained cross section and the Westcott factor are compared with the preceding experiments and evaluated values.

論文

Measurements of capture $$gamma$$ rays from the neutron resonances of $$^{74}$$Se and $$^{77}$$Se at the J-PARC/MLF/ANNRI

堀 順一*; 八島 浩*; 中村 詔司; 古高 和禎; 原 かおる; 原田 秀郎; 廣瀬 健太郎; 木村 敦; 北谷 文人; 小泉 光生; et al.

Nuclear Data Sheets, 119, p.128 - 131, 2014/05

https://doi.org/10.1016/j.nds.2014.08.036
 被引用回数：4 パーセンタイル：32.87(Physics, Nuclear)

本研究では、$$^{74}$$Seと$$^{77}$$Seの中性子共鳴からの捕獲$$gamma$$線を測定した。$$^{74}$$Seは、簡単な殻模型から2p$$_{1/2}$$軌道まで中性子が占有されている偶-偶核であるので、プライマリ$$gamma$$線遷移の始状態と終状態間の強い相関が予想される。$$^{74}$$Seは、安定Se同位体の中で唯一の奇数核であるので、同じ奇数核である$$^{79}$$Seの評価に資する情報を含んでいると期待される。J-PARC、物質・生命科学実験施設(MLF)の中性子核反応実験装置(ANNRI)に整備した4$$pi$$ Geスペクトロメータを用いて、飛行時間法により測定を行った。$$^{74}$$Seの27eV共鳴、及び$$^{77}$$Seの113eV, 212eV, 291eV, 342eV, 690eV及び864eV共鳴に対応する$$gamma$$線波高スペクトルを得た。これらのプライマリ遷移$$gamma$$線の相対強度を求め、報告されている実験データと比較を行った。$$^{74}$$Seの27eV共鳴について、293keV準位への強いプライマリ遷移が観測された。$$^{77}$$Seについては、共鳴ごとに全く異なる崩壊パターンを見いだした。

論文

Cross section measurement of $$^{237}$$Np$$(n,gamma)$$ at J-PARC/MLF/ANNRI

廣瀬 健太郎; 古高 和禎; 原 かおる; 原田 秀郎; 堀 順一*; 井頭 政之*; 加美山 隆*; 片渕 竜也*; 木村 敦; 金 政浩*; et al.

Nuclear Data Sheets, 119, p.48 - 51, 2014/05

https://doi.org/10.1016/j.nds.2014.08.015
 被引用回数：1 パーセンタイル：10.19(Physics, Nuclear)

The cross section of the $$^{237}$$Np$$(n,gamma)$$ reaction has been measured in an energy range from 10 meV to 1 keV at the Japan Proton Accelerator Research Complex (J-PARC). The NaI(Tl) spectrometer installed in the accurate neutron-nucleus reaction measurement instrument (ANNRI) was used for the measurement. The relative cross section was obtained using the neutron spectrum measured by the $$^{10}$$B$$(n,alpha_1)$$ reaction. The absolute value of the cross section was deduced by normalizing the relative cross section to the evaluated value in JENDL-4.0 at the first resonance. In this presentation, the obtained results for the cross section, the Westcott factor and the resonance analysis are reported. This work was supported by JSPS KAKENHI Grant Number 22226016.

論文

Transmission secondary ion mass spectrometry using 5 MeV C$$_{60}$$$$^{+}$$ ions

中嶋 薫*; 永野 賢悟*; 鈴木 基史*; 鳴海 一雅; 齋藤 勇一; 平田 浩一*; 木村 健二*

Applied Physics Letters, 104(11), p.114103_1 - 114103_4, 2014/03

https://doi.org/10.1063/1.4868655
 被引用回数：6 パーセンタイル：26.7(Physics, Applied)

In the secondary ion mass spectrometry (SIMS), use of cluster ions has an advantage of having a high sensitivity of intact large molecular ions over monatomic ions. This paper presents further yield enhancement of the intact biomolecular ions with measuring the secondary ions emitted from a self-supporting thin film in the forward direction, which is the same direction as primary beams. Phenylalanine amino-acid films deposited on self-supporting thin Si$$_{3}$$N$$_{4}$$ films were bombarded with 5-MeV C$$_{60}$$$$^{+}$$ ions. Secondary ions emitted in the forward and backward directions were measured under the bombardments of the SiN and phenylalanine sides, respectively. The yield of intact phenylalanine molecular ions emitted in the forward direction is about one order of magnitude larger than the backward direction, while fragment ions of phenylalanine molecules are suppressed. This suggests a large potential of transmission cluster-ion SIMS for the analysis of biological materials.

論文

Energy resolution of pulsed neutron beam provided by the ANNRI beamline at the J-PARC/MLF

木野 幸一*; 古坂 道弘*; 平賀 富士夫*; 加美山 隆*; 鬼柳 善明*; 古高 和禎; 後神 進史*; 原 かおる; 原田 秀郎; 原田 正英; et al.

Nuclear Instruments and Methods in Physics Research A, 736, p.66 - 74, 2014/02

https://doi.org/10.1016/j.nima.2013.09.060
 被引用回数：31 パーセンタイル：91.7(Instruments & Instrumentation)

We studied the energy resolution of the pulsed neutron-beam of Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) at the Japan Proton Accelerator Research Complex/Materials and Life Science Experimental Facility (J-PARC/MLF). A simulation in the energy region from 0.7 meV to 1 MeV has been performed. Moreover, measurements have been done in the thermal and epithermal energies. The neutron energy resolution at ANNRI, which is determined by the time-of-flight technique, depends on the time structure of the neutron pulse. We obtained the neutron energy resolution as a function of the neutron energy by the simulation in the two operation modes of the neutron source: double and single bunch modes. In the double bunch mode, the resolution deteriorates above about 10 eV because the time structure of the neutron pulse splits into two peaks. The time structures at 13 energy points by measurements in the thermal energy region are in agreement with those of the simulation. In the epithermal energy region, the time structures at 17 energy points were obtained by measurements. The FWHM values of the time structures by the simulation and measurements are almost consistent. In the single bunch mode, the energy resolution is better than about 1% between 1 meV and 10 keV at the neutron source operation of 17.5 kW.

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