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論文

Development of an integrated non-destructive analysis system, Active-N

土屋 晴文; 藤 暢輔; 大図 章; 古高 和禎; 北谷 文人; 前田 亮; 米田 政夫

Journal of Nuclear Science and Technology, 60(11), p.1301 - 1312, 2023/11

 被引用回数:0 パーセンタイル:75.85(Nuclear Science & Technology)

An integrated active neutron non-destructive analysis (NDA) system, Active-N, was developed to gain knowledge of active neutron NDA techniques that are applicable to measurements of nuclear materials in highly radioactive nuclear fuels. Active-N, equipped with a D-T neutron generator, combines three complementary active neutron NDA techniques: Differential Die-away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), and Neutron Resonance Transmission Analysis (NRTA). In this paper, we provide an overview of Active-N and then demonstrate that the compact NRTA system in Active-N can quantify nuclear materials. Monte Carlo simulations were conducted to determine the design of the compact NRTA system including a moderator, flight tubes, and a detector shield. To investigate how accurately the compact NRTA system determines areal densities in a sample, measurements were performed with a Pu pellet-type sample as well as metallic plate samples of In and Ag. The experimental areal densities of $$^{240}$$Pu, $$^{115}$$In and $$^{109}$$Ag were consistent with those calculated for the individual nuclei. These results show that it is feasible to develop a compact NRTA system capable of determining the contents of nuclear materials in nuclear fuels. This research was implemented under the subsidy for nuclear security promotion of MEXT.

論文

Development of a DDA+PGA-combined non-destructive active interrogation system in "Active-N"

古高 和禎; 大図 章; 藤 暢輔

Nuclear Engineering and Technology, 55(11), p.4002 - 4018, 2023/11

An integrated neutron interrogation system has been developed for non-destructive assay of highly radioactive special nuclear materials, to accumulate knowledge of the method through developing and using it. The system combines a differential die-away (DDA) measurement system for the quantification of nuclear materials and a prompt gamma-ray analysis (PGA) system for the detection of neutron poisons which disturb the DDA measurements; a common D-T neutron generator is used. A special care has been taken for the selection of materials to reduce the background gamma rays produced by the interrogation neutrons. A series of measurements were performed to test the basic performance of the system. The results show that the DDA system can quantify plutonium of as small as 20~mg and it is not affected by intense neutron background up to 4.2~TBq and gamma ray of 2.2~TBq. As a result of the designing of the combined system as a whole, the gamma-ray background counting rate at the PGA detector was reduced down to $$3.9times10^{3}$$ s$$^{-1}$$ even with the use of the D-T neutron generator. The test measurements show that the PGA system is capable of detecting less than 1~g of boron compound and about 100~g of gadolinium compound in~30 min. This research was implemented under the subsidy for nuclear security promotion of MEXT.

論文

Development of an integrated active neutron non-destructive analysis system; Active-N

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 小泉 光生

Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 8 Pages, 2021/08

Since neutrons have exceptional ability to penetrate high-density materials and can induce fission, they are used in non-destructive analysis such as, Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA) and Neutron Resonance Transmission Analysis (NRTA). The different analytical methods give us complementary information, which are particularly useful for the quantification of Special Nuclear Materials in highly radioactive nuclear materials, including spent fuel. The Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission are collaborating to develop an active neutron NDA system for nuclear non-proliferation and nuclear security. In the second phase of the project, an integrated active neutron NDA system: Active-N which enables the simultaneous measurements of DDA, PGA and NRTA has been developed. The DDA detects fission neutrons, and it can determine small amounts of the fissile mass. PGA is utilized for the quantification of neutron absorber and particularly useful for the detection of explosives. NRTA can be used to quantify almost all medium and high-Z elements and considered as one of the most accurate NDA. In this presentation, we will provide an overview of Active-N and report the recent experimental results. This research was implemented under the subsidy for nuclear security promotion of MEXT: Ministry of Education, Culture, Sports, Science and Technology.

論文

The Design and implementation of the PGA measurement system in an integrated Active Neutron non-destructive analysis system, "Active-N"

古高 和禎; 大図 章; 藤 暢輔

Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 9 Pages, 2021/08

We have been developing an integrated active neutron non-destructive analysis system for highly radioactive nuclear materials, "Active-N", using an intense D-T neutron source. The system is composed of the following mutually complementing different measurement systems: Differential Die-away Analysis (DDA), Neutron Resonance Transmission Analysis (NRTA), and Prompt Gamma-ray Analysis (PGA). The former two are for measurements of total amount of fissile material and of isotopic composition, respectively. The purpose of the last one, i.e. PGA measurement system is the detection of explosives contained in e.g., dirty bombs and of chemical warfare agents, as well as of neutron poisons which absorb neutrons and disturb DDA measurements. This report describes mainly the PGA measurement system. In the PGA measurement system, to resolve individual gamma-ray peaks, a Ge detector is utilized. It is well known that irradiation of fast neutrons ($$gesim10$$ keV) to Ge detectors cause damages to the detectors and gradually worsen their resolution, and finally make them unusable without a laborious treatment. Therefore, it is essential to shield the PGA detector against the neutrons from the D-T neutron generator. In addition, to reduce background gamma rays from the materials used for the DDA system, they should also be carefully chosen. In order to design an appropriate neutron shield for the PGA measurement system and diminish the sources of the background gamma rays, simulation study was done using a particle transport code system PHITS. Based on the results, a shielding for the PGA measurement system has been designed which reduces the number of damaging neutrons by an order of magnitude. The Active-N system which incorporates the PGA measurement system equipped with the neutron shielding, has been installed at NUCEF facility in JAEA Tokai. This research was implemented under the subsidy for nuclear security promotion from MEXT.

論文

High-spin states in $$^{35}$$S

郷 慎太郎*; 井手口 栄治*; 横山 輪*; 青井 考*; Azaiez, F.*; 古高 和禎; 初川 雄一; 木村 敦; 木佐森 慶一*; 小林 幹*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

 被引用回数:4 パーセンタイル:58.42(Physics, Nuclear)

Excited states in $$^{35}$$S were investigated by in-beam $$gamma$$-ray spectroscopy using the $$^{26}$$Mg($$^{18}$$O, 2$$alpha$$1$$n$$) fusion-evaporation reaction. The de-exciting $$gamma$$-rays were measured with germanium detector arrays along with the measurement of evaporated charged particles in a $$4pi$$ segmented Si detector array. The level scheme was extended up to 12470 keV. The obtained level structure is compared with the large-scale shell-model calculations. The possibility of isoscalar-pair excited states is discussed for $$J=(17/2)$$ states with comparison between the experimental and theoretical results.

論文

Study of shields against D-T neutrons for Prompt Gamma-ray Analysis apparatus in Active-N

古高 和禎; 藤 暢輔

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.297 - 304, 2020/10

No established method exists to non-destructively measure the amount of highly radioactive nuclear fuel materials such as spent fuels, and it is one of the urgent issues in nuclear material accountancy. Therefore, JAEA has started a research on development of innovative non-destructive analysis (NDA) system for Special Nuclear Materials and Minor Actinides, in cooperation with EC-JRC. The aim of the project is to establish an NDA method which can be applied to highly radioactive nuclear materials and develop a demonstration system, named "Active-N", by utilizing an intense D-T neutron source and by combining the following mutually complemental active-neutron NDA methods: DDA, N RTAs, and PGA (Prompt Gamma-ray Analysis). The PGA measurements play a crucial role in the system, because it can detect/quantify neutron poison elements which disturb DDA measurements, as well as explosives and chemical warfare agents, by utilizing a high-energy resolution Germanium detector. To make an NDA system to be efficient one, an intense neutron generator has to be employed. On the other hand, exposure of a Ge detector to an immense amount of fast neutron makes the detector severely damaged and inoperative. Therefore, in order for the system to be efficient, it is essential to develop effective shield of the PGA system against fast neutrons. In this work, by performing particle transport calculation using Monte Carlo method, we have investigated effective shielding methods for the PGA measurement system in the Active-N system, against fast neutrons from the D-T neutron source. Materials and their configurations which effectively reduce fast-neutron doses and at the same time emit no interfering gamma rays, were examined. Through the calculation, a shield which reduces fast neutron dose sufficiently have been developed. This research was implemented under the subsidiary for nuclear security promotion of MEXT.

論文

Simulation study on the design of nondestructive measurement system using fast neutron direct interrogation method to nuclear materials in fuel debris

前田 亮; 古高 和禎; 呉田 昌俊; 大図 章; 米田 政夫; 藤 暢輔

Journal of Nuclear Science and Technology, 56(7), p.617 - 628, 2019/07

 被引用回数:2 パーセンタイル:32.21(Nuclear Science & Technology)

In order to measure the amount of nuclear materials in the fuel debris produced in the Fukushima Daiichi Nuclear Power Plant accident, we have designed a measurement system based on a Fast Neutron Direct Interrogation (FNDI) method. In particular, we have developed a fast response detector bank for fast neutron measurements by Monte Carlo simulations. The new bank has more than an order of magnitude faster response compared to the standard ones. We have also simulated the nondestructive measurements of the nuclear materials in homogeneously mixed fuel debris with various matrices which contain Stainless Steel (JIS SUS304), concrete, and various control-rod (CR) contents in the designed system. The results show that at least some types of the fissile materials in the debris can be measured by using the designed system.

論文

Development of active neutron NDA system for radioactive nuclear materials

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 小泉 光生

Proceedings of INMM 60th Annual Meeting (Internet), 7 Pages, 2019/07

Nuclear material accountancy plays a key role in nuclear safeguards and security. The collaboration between the Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission aims to develop an active neutron NDA system for Special Nuclear Materials (SNM) and Minor Actinides (MA) in highly radioactive nuclear materials. Several active neutron NDA techniques, namely Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma-ray Analysis (DGA) have been developed. The different methods can provide complementary information. In the first phase of the project, we developed a combined NDA system, which enables the simultaneous measurements of DDA and PGA. The DDA technique can determine very small amounts of the fissile mass. PGA is valuable for the measurement of light elements. In the second phase, we will continue to conduct additional research to improve the methodology and develop a new integrated NDA system which can use for NRTA as well as DDA and PGA. In this presentation, we will provide an overview of the project and report the recent results, especially the design of new integrated NDA system. This research was implemented under the subsidiary for nuclear security promotion of MEXT.

論文

Development of active neutron NDA system for nuclear materials

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 小泉 光生; Heyse, J.*; Paradela, C.*; et al.

Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07

Nuclear material accountancy is of fundamental importance for nuclear safeguards and security. However, to the best of our knowledge, there is no established technique that enables us to accurately determine the amount of Special Nuclear Materials (SNM) and Minor Actinides (MA) in high radioactive nuclear materials. Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission Collaboration Action Sheet-7 started in 2015. The purpose of this project is to develop an innovative non-destructive analysis (NDA) system using a D-T pulsed neutron source. Active neutron NDA techniques, namely Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma-ray Analysis (DGA) have been studied and developed. The different methods can provide complementary information which is particularly useful for quantification of SNM and MA in high radioactive nuclear materials. The second phase of the project has started. In the second phase, we will continue to conduct additional research to improve the methodology and develop an integrated NDA system. This presentation gives an overview of the project and the NDA system and reports the recent results. This research was implemented under the subsidiary for nuclear security promotion of MEXT.

論文

核不拡散・核セキュリティ用アクティブ中性子NDA技術の開発,1; 次世代型DDA装置の性能評価

大図 章; 前田 亮; 米田 政夫; 古高 和禎; 藤 暢輔

日本核物質管理学会第38回年次大会論文集(インターネット), 9 Pages, 2018/04

原子力機構では、欧州委員会共同研究センターと共同で核不拡散、核セキュリティ用非破壊測定技術の開発に取り組んでおり、従来の技術では測定が難しい核変換用MA-Pu燃料等の高線量核物質や共存物質が多い難測定核物質を測定する技術の確立を目指している。その技術開発において、核分裂性核物質の定量が可能な次世代型アクティブ中性子ダイアウェイ時間差分析(DDA)部と元素分析が可能な即発$$gamma$$線分析(PGA)部を組み合わせた、小型DT中性子源を用いるアクティブ中性子統合非破壊測定試験装置"Active-N"を新たに設計、開発した。現在、製作したDDA部の基本性能を評価するために微量のPu酸化物試料を封入したバイアル瓶を用いて測定試験を実施している。本報では、その試験結果をモンテカルロシミュレーション(MCNP)結果と比較して報告する。

論文

Development of active neutron NDA techniques for nuclear nonproliferation and nuclear security

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 呉田 昌俊; 小泉 光生; 瀬谷 道夫; et al.

EUR-28795-EN (Internet), p.684 - 693, 2017/00

In 2015, Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission collaboration started to develop an active neutron non-destructive assay system for nuclear nonproliferation and nuclear security. To the best of our knowledge, no adequate technique exists that allows us to determine the amount of special nuclear materials and minor actinides in high radioactive nuclear materials, such as spent fuel, transuranic waste, etc. The collaboration aims at contributing to the establishment of an innovative NDA system using a D-T pulsed neutron source for various applications. We utilize several active neutron NDA techniques, namely Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma Spectroscopy (DGS). All of these techniques have advantages and disadvantages. The different methods can provide complementary information which is particularly useful for nuclear nonproliferation and nuclear security. In this project, we have developed a combined NDA system, which enables the measurements of DDA and PGA, at NUclear fuel Cycle safety Engineering research Facility (NUCEF) in JAEA. In this presentation, we will introduce our project and report the recent progress of developments, especially in NRTA, DDA and PGA.

論文

Applicability evaluation of candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station; Active neutron technique (Interim report)

米田 政夫; 前田 亮; 古高 和禎; 飛田 浩; 服部 健太朗; 下総 太一; 大図 章; 呉田 昌俊

Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07

FNDI法を用いた非破壊計量管理システムの開発を行っている。FNDI法はアクティブ法測定の一種であり、誘発核分裂核種(U-235, Pu-239, Pu-241)の総量を求めることができる。これまでに、TMIのキャニスタを仮定したデブリ計測システムの設計解析を実施しており、その結果はINMM-56において発表している。その後、福島第一原子力発電所燃料デブリ用キャニスタ及びデブリ組成の計算モデルの検討を行い、その結果を用いたデブリ計測システムの改良を進めてきた。本発表では、その新しいNDA計測システムを用いたデブリ測定の解析及び評価結果を示す。それに加え、多くの核物質を含むデブリが測定に与える影響について、解析による検討結果を示す。

論文

Current activities and future plans for nuclear data measurements at J-PARC

木村 敦; 原田 秀郎; 中村 詔司; 岩本 修; 藤 暢輔; 小泉 光生; 北谷 文人; 古高 和禎; 井頭 政之*; 片渕 竜也*; et al.

European Physical Journal A, 51(12), p.180_1 - 180_8, 2015/12

 被引用回数:2 パーセンタイル:30.26(Physics, Nuclear)

In order to improve the data accuracy of neutron-capture cross sections of minor actinides (MAs) and long-lived fission products (LLFPs), a new experimental instrument named "Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI)" has been constructed in the Materials and Life science experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), and measurements of neutron-capture cross sections of MAs, LLFPs and some stable isotopes with high intensity pulsed neutrons have been started. The analyses for $$^{244}$$Cm, $$^{246}$$Cm, $$^{241}$$Am and $$^{237}$$Np were finished; those for $$^{129}$$I, $$^{107}$$Pd, $$^{99}$$Tc, $$^{93}$$Zr and some stable isotopes are in progress. These results will make significant contributions in the field of developing innovative nuclear systems.

論文

高速中性子直接問いかけ法を用いた燃料デブリ内核物質非破壊測定に関する研究

前田 亮; 古高 和禎; 呉田 昌俊; 大図 章; 飛田 浩; 米田 政夫; 服部 健太朗

核物質管理学会(INMM)日本支部第36回年次大会論文集(インターネット), 9 Pages, 2015/12

2011年3月11日に発生した福島第一原子力発電所事故により、燃料デブリが発生しているとされている。燃料デブリはその組成が不明で、水,中性子吸収材,金属等が含まれていることが予想されるため、デブリ内核物質の非破壊測定には困難が伴うと考えられる。一方、廃棄物中の核物質測定のために長年研究されてきた高速中性子直接問いかけ(FNDI)法は、測定対象の組成に依存せずに核物質量の測定が可能である。この特長に着目してFNDI法を用いた燃料デブリ内核物質の非破壊測定を目的とした研究に着手した。本報では、燃料デブリ収納缶を対象とした非破壊測定システムの設計と燃料デブリの組成が変化した時のFNDI法の適用性についてモンテカルロ・シミュレーションを用いて行った検討結果を報告する。

論文

核不拡散用アクティブ中性子非破壊測定技術の開発,1; 開発計画

呉田 昌俊; 小泉 光生; 大図 章; 土屋 晴文; 古高 和禎; 瀬谷 道夫

核物質管理学会(INMM)日本支部第36回年次大会論文集(インターネット), 9 Pages, 2015/12

原子力機構は、欧州委員会共同研究センター(EC-JRC)との国際共同研究による核不拡散分野用途の「アクティブ中性子非破壊測定技術開発」に着手した。本研究課題の最終目標は、MA核変換用MA-Pu燃料など高線量核燃料の非破壊測定装置への適用を目指した核物質測定技術を確立することである。高線量核燃料の非破壊測定については、Pu-240等が放出する中性子に着目した同時計数法など従来のパッシブ測定技術の適用が困難となることが予想されている。しかし、これまで系統的に研究は成されておらず、計測技術が確立していない課題があった。本研究課題では、アクティブ中性子法であるDDA法, NRTA法, PGA/NRCA法, DGS法による核物質測定技術の研究開発を行う。本報では、開発計画と統合試験装置(Active-N)の設計研究について報告する。

論文

Development of a measurement system for the determination of ($$n,gamma$$) cross-sections using multi-nucleon transfer reactions

牧井 宏之; 太田 周也*; 石井 哲朗; 若林 泰生*; 古高 和禎; 西尾 勝久; 西中 一朗; 千葉 敏; 井頭 政之*; Czeszumska, A.*

Nuclear Instruments and Methods in Physics Research A, 797, p.83 - 93, 2015/10

 被引用回数:4 パーセンタイル:33.51(Instruments & Instrumentation)

中性子捕獲断面積を間接的に導出するための、$$gamma$$線測定用のコンプトン抑止型LaBr$$_{3}$$(Ce)検出器と荷電粒子測定用のシリコン$${Delta}E$$-$$E$$検出器から構成される、新しい測定装置の開発を行った。原子力機構タンデム加速器からのエネルギー153MeVの酸素18ビームを$$^{155}$$Gd及び、$$^{157}$$Gd標的に照射して発生する$$gamma$$線と荷電粒子の同時測定を行うことにより、開発した装置の特性試験を行った。大型(直径4インチ、長さ5インチ)のLaBr$$_{3}$$(Ce)検出器を用いることにより、$$^{155}$$Gd($$^{18}$$O, $$^{16}$$O)$$^{157}$$Gd反応及び、$$^{157}$$Gd($$^{18}$$O, $$^{16}$$O)$$^{159}$$Gd反応で生成される複合核からの$$gamma$$線の測定に成功した。得られた結果から新たに開発した測定装置が多核子移行反応を用いた中性子捕獲断面積の導出に極めて有効であることを見出した。

論文

JAEA-JRC collaboration on the development of active neutron NDA techniques

呉田 昌俊; 小泉 光生; 大図 章; 古高 和禎; 土屋 敬広*; 瀬谷 道夫; 原田 秀郎; Abousahl, S.*; Heyse, J.*; Kopecky, S.*; et al.

Proceedings of 37th ESARDA Annual Meeting (Internet), p.111 - 120, 2015/08

原子力機構は、EC-JRCとの国際共同研究による「アクティブ中性子非破壊測定技術開発」に着手した。本研究課題の最終目標は、MA核変換用MA-Pu燃料など高線量核燃料や、核セキュリティ関連装置への適用を目指した核物質測定技術を確立することである。本研究課題では、アクティブ中性子法であるDDA法, NRTA法, PGA/NRCA法, DGS法による核物質測定技術の研究開発を行う。

論文

Simulation study on non-destructive assay for fuel debris by using Fast Neutron Direct Interrogation (FNDI) method

前田 亮; 古高 和禎; 呉田 昌俊; 大図 章; 飛田 浩; 米田 政夫; 服部 健太朗

Proceedings of INMM 56th Annual Meeting (Internet), 8 Pages, 2015/07

原子力機構では、核物質の総量の非破壊測定法として有望な高速中性子直接問いかけ法の福島第一原子力発電所燃料デブリへの適用可能性の検討を開始した。本講演では、モンテカルロシミュレーションコードPHITSを用いて設計した非破壊測定装置の基本設計とモンテカルロシミュレーションコードMVPを用いて予測した燃料デブリの組成と測定値との関係及び、我々が新たに開発したツールを用いた中性子束分布の4次元可視化結果について報告する。

論文

Development of active neutron NDA techniques for nuclear non-proliferation applications

呉田 昌俊; 小泉 光生; 大図 章; 古高 和禎; 土屋 晴文; 瀬谷 道夫

Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07

原子力機構は、核不拡散分野用途の「アクティブ中性子非破壊測定技術開発」に着手した。本研究課題の最終目標は、MA核変換用MA-Pu燃料など高線量核燃料の非破壊測定装置への適用を目指した核物質測定技術を確立することである。本研究課題では、アクティブ中性子法であるDDA法, NRTA法, PGA/NRCA法, DGS法による核物質測定技術の研究開発を行う。

論文

Superdeformation in $$^{35}$$S

郷 慎太郎*; 井手口 栄治*; 横山 輪*; 小林 幹*; 木佐森 慶一*; 高木 基伸*; 宮 裕之*; 大田 晋輔*; 道正 新一郎*; 下浦 享*; et al.

JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06

The high-spin states in $$^{35}$$S were investigated at Tandem-ALTO facility in Institut de Physique Nucl$'e$aire d'Orsay The $$^{26}$$Mg($$^{18}$$O, 2$$alpha$$1n)$$^{35}$$S fusion evaporation reaction was used to populate high-spin states in $$^{35}$$S. The germanium $$gamma$$-ray detector array ORGAM was employed to measure $$gamma$$ rays from high-spin states and charged particles evaporated from the compound nuclei were detected by a segmented silicon detector, Si-Ball. A level scheme for $$^{35}$$S was deduced based on the gamma-gamma-coincidence analysis and $$gamma$$-ray angular correlation analysis. The half-life of the transition in the superdeformed band was estimated by measuring the residual Doppler shift. The deduced half-life shows the large collectivity of the band.

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