Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 27

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring

Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.

Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01

 Times Cited Count:5 Percentile:64.12(Instruments & Instrumentation)

Journal Articles

First direct mass measurements of nuclides around $$Z$$ = 100 with a multireflection time-of-flight mass spectrograph

Ito, Yuta*; Schury, P.*; Wada, Michiharu*; Arai, Fumiya*; Haba, Hiromitsu*; Hirayama, Yoshikazu*; Ishizawa, Satoshi*; Kaji, Daiya*; Kimura, Sota*; Koura, Hiroyuki; et al.

Physical Review Letters, 120(15), p.152501_1 - 152501_6, 2018/04

 Times Cited Count:60 Percentile:93.54(Physics, Multidisciplinary)

Masses of $$^{246}$$Es, $$^{251}$$Fm and the transfermium nuclei $$^{249-252}$$Md, and $$^{254}$$No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed $$N=152$$ neutron shell closure, have been directly measured using a multi-reflection time-of-flight mass spectrograph. The masses of $$^{246}$$Es and $$^{249,250,252}$$Md were measured for the first time. Using the masses of $$^{249,250}$$Md as anchor points for $$alpha$$ decay chains, the masses of heavier nuclei, up to $$^{261}$$Bh and $$^{266}$$Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter $$delta_{2n}$$ derived from three isotopic masses was updated with the new masses and corroborate the existence of the deformed $$N=152$$ neutron shell closure for Md and Lr.

JAEA Reports

Pretreatment works for disposal of radioactive wastes produced by research activities, 1

Ishihara, Keisuke; Yokota, Akira; Kanazawa, Shingo; Iketani, Shotaro; Sudo, Tomoyuki; Myodo, Masato; Irie, Hirobumi; Kato, Mitsugu; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.

JAEA-Technology 2016-024, 108 Pages, 2016/12

JAEA-Technology-2016-024.pdf:29.74MB

Radioactive isotope, nuclear fuel material and radiation generators are utilized in research institutes, universities, hospitals, private enterprises, etc. As a result, various low-level radioactive wastes (hereinafter referred to as non-nuclear radioactive wastes) are produced. Disposal site for non-nuclear radioactive wastes have not been settled yet and those wastes are stored in storage facilities of each operator for a long period. The Advanced Volume Reduction Facilities (AVRF) are built to produce waste packages so that they satisfy requirements for shallow underground disposal. In the AVRF, low-level beta-gamma solid radioactive wastes produced in the Nuclear Science Research Institute are mainly treated. To produce waste packages meeting requirements for disposal safely and efficiently, it is necessary to cut large radioactive wastes into pieces of suitable size and segregate those depending on their types of material. This report summarizes activities of pretreatment to dispose of non-nuclear radioactive wastes in the AVRF.

Journal Articles

A Multi-reflection time-of-flight mass spectrograph for short-lived and super-heavy nuclei

Schury, P. H.*; Wada, Michiharu*; Ito, Yuta*; Naimi, S.*; Sonoda, Tetsu*; Mita, Koki*; Takamine, Aiko*; Okada, Kunihiro*; Wollnik, H.*; Chon, S.*; et al.

Nuclear Instruments and Methods in Physics Research B, 317(Part B), p.537 - 543, 2013/12

 Times Cited Count:28 Percentile:89.64(Instruments & Instrumentation)

A multi-reflection time-of-flight (MRTOF) mass spectrograph has been implemented at RIKEN to provide high-precision mass measurements of very short-lived nuclei. Of particular interest are mass measurements of r-process nuclei and trans-uranium nuclei. In such nuclei, the MRTOF can perform on par with or better than traditional Penning trap systems. We demonstrate that the MRTOF-MS is capable of accurately attaining relative mass precision of $$delta$$m/m $$<$$ 10$$^{-7}$$ and describe it's utility with heavy, short-lived nuclei.

Journal Articles

New result in the production and decay of an isotope, $$^{278}$$113 of the 113th element

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.

Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10

 Times Cited Count:167 Percentile:97.31(Physics, Multidisciplinary)

An isotope of the 113th element, $$^{278}$$113, was produced in a nuclear reaction with a $$^{70}$$Zn beam on a $$^{209}$$Bi target. We observed six consecutive $$alpha$$ decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of $$^{262}$$Db and $$^{258}$$Lr both in decay energies and decay times. This indicates that the present decay chain consisted of $$^{278}$$113, $$^{274}$$Rg (Z = 111), $$^{270}$$Mt (Z = 109), $$^{266}$$Bh (Z = 107), $$^{262}$$Db (Z = 105), and $$^{258}$$Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope $$^{278}$$113, of the 113th element.

Journal Articles

Production and decay properties of $$^{264}$$Hs and $$^{265}$$Hs

Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Kaji, Daiya*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sumita, Takayuki*; Yoneda, Akira*; et al.

Journal of the Physical Society of Japan, 80(9), p.094201_1 - 094201_7, 2011/09

 Times Cited Count:15 Percentile:65.21(Physics, Multidisciplinary)

Decay properties of $$^{264}$$Hs and $$^{265}$$Hs produced in the $$^{207,208}$$Pb($$^{58}$$Fe, $$xn$$) [$$x$$=1, 2] reactions were studied using a gas-filled recoil ion separator at the linear accelerator facility of RIKEN. A total of 6 decay chains were assigned to $$^{264}$$Hs. Cross sections for the $$^{264}$$Hs production in the $$^{208}$$Pb($$^{58}$$Fe,$$2n$$) and $$^{207}$$Pb($$^{58}$$Fe,$$n$$) reactions were measured to be $$2.8^{+6.5}_{-2.3}$$pb and $$6.9^{+4.4}_{-3.1}$$pb, respectively. The isotope $$^{264}$$Hs decayed with a half-life of $$0.751^{+0.518}_{-0.218}$$ms by $$alpha$$-particle emission and spontaneous fission. The $$alpha$$-particle energy of $$^{264}$$Hs was observed at 10.61$$pm$$0.04 and 10.80$$pm$$0.08 MeV. The spontaneous fission branch of $$^{264}$$Hs was found to be $$17^{+38}_{-14}%$$.

Journal Articles

Spins and parities of astrophysically important $$^{30}$$S states from $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S

Setoodehnia, K.*; Chen, A. A.*; Komatsubara, Tetsuro*; Kubono, Shigeru*; Binh, D. N.*; Carpino, J. F.*; Chen, J.*; Hashimoto, Takashi*; Hayakawa, Takehito; Ishibashi, Yoko*; et al.

Physical Review C, 83(1), p.018803_1 - 018803_4, 2011/01

 Times Cited Count:12 Percentile:60.62(Physics, Nuclear)

The structure of proton-unbound $$^{30}$$S states strongly determines the thermonuclear $$^{29}$$P($$p$$, $$gamma$$)$$^{30}$$S reaction rate at temperatures characteristic of explosive hydrogen burning in classical novae and type I X-ray bursts. Specifically, the rate had been previously predicted to be dominated by two low-lying, unobserved, levels in the $$E$$$$_{x}$$=4.7-4.8 MeV region, with spin and parity assignments of 3$$^{+}$$ and 2$$^{+}$$. In recent experimental work, two candidate levels were observed with energies of 4.699 MeV and 4.814 MeV, but no experimental information on their spins and parities was obtained. We have performed an in-beam $$gamma$$-ray spectroscopy study of $$^{30}$$S with the $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S reaction. The spin and parities were inferred from a comparison to the known decay schemes of the corresponding mirror states.

Journal Articles

Decay properties of $$^{266}$$Bh and $$^{262}$$Db produced in the $$^{248}$$Cm + $$^{23}$$Na reaction

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi*; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

Journal of the Physical Society of Japan, 78(6), p.064201_1 - 064201_6, 2009/06

 Times Cited Count:30 Percentile:78.29(Physics, Multidisciplinary)

Decay properties of an isotope $$^{266}$$Bh and its daughter nucleus $$^{262}$$Db produced by the $$^{248}$$Cm($$^{23}$$Na,5$$n$$) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. $$^{266}$$Bh was clearly identified from the correlation of the known nuclide, $$^{262}$$Db. The obtained decay properties of $$^{266}$$Bh and $$^{262}$$Db are consistent with those observed in the $$^{278}$$113 chain, which provided further confirmation of the discovery of $$^{278}$$113.

Journal Articles

Production of a new hassium isotope $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.

Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03

A new hassium isotopes $$^{263}$$Hs is directly produced for the first time. The experiment was performed at the linear accelerator (RILAC) facility in RIKEN (the Institute of Physical and Chemical Research) from Jun. 19 to 25. In the 25-h irradiation of $$^{58}$$Fe on $$^{206}$$Pb and 46-h irradiation of $$^{56}$$Fe on $$^{208}$$Pb, 8 decay chains and 1 decay chain, respectively, were observed. All decay chains were assigned to subsequent decays from $$^{263}$$Hs. The half-life of $$^{263}$$Hs is 0.60$$^{+0.30}_{-0.15}$$ ms. In this experiment, the total beam dose was $$4.1times10^{17}$$ ions for $$^{58}$$Fe and $$6.2times10^{17}$$ ions for $$^{56}$$Fe. The production cross section corresponding to 8 decay events and 1 decay chain was deduced to be 21$$^{+10}_{-8}$$ pb and 1.6$$^{+3.7}_{-1.3}$$ pb by assuming that the transmission of the system is 80%.

Journal Articles

Production and decay properties of $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.

Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03

 Times Cited Count:3 Percentile:26.24(Physics, Multidisciplinary)

A new neutron deficient hassium ($$Z$$=108) isotope of $$^{263}$$Hs was identified via two different reactions of $$^{206}$$Pb($$^{58}$$Fe,n) and $$^{208}$$Pb($$^{56}$$Fe,n) by using a gas-filled recoil separator GARIS at June 2008. During the 25-h irradiation of $$^{206}$$Pb with the $$^{58}$$Fe beam and 46-h irradiation of $$^{208}$$Pb with the $$^{56}$$Fe beam, 8 decay chains and 1 decay chain, respectively, have been observed. The half-life of $$^{263}$$Hs is 0.60$$^{+0.30}_{0.15}$$ ms. In this experiment, the total beam doses of the Fe and $$^{56}$$Fe was 4.1$$times$$10$$^{17}$$ ions and 6.2$$times$$10$$^{17}$$ ions, respectively. The production cross sections corresponding to the 8 decay chains and 1 decay chain have been deduced to be 21$$^{+10}_{-8}$$ pb and 1.6$$^{+3.7}_{-1.3}$$ pb by assuming the transmission of the system to be 80%.

Journal Articles

New decay properties of $$^{264}$$Hs, $$^{260}$$Sg, and $$^{256}$$Rf

Sato, Nozomi*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Kaji, Daiya*; Koura, Hiroyuki; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozawa, Akira*; et al.

RIKEN Accelerator Progress Report, Vol.42, P. 16, 2009/00

New Decay Properties of $$^{264}$$Hs and its $$alpha$$-decay daughter nuclei were studied by using reactions of $$^{208}$$Pb($$^{58}$$Fe,2n) and $$^{207}$$Pb($$^{58}$$Fe,n) by using a gas-filled recoil ion separator, GARIS at RIKEN. We observed three correlated events in irradiation of $$^{58}$$Fe on $$^{208}$$Pb, and eight events in irradiation of $$^{58}$$Fe on $$^{207}$$Pb. A half-life was deduced to be 0.90$$^{+0.40}_{-0.20}$$. We assigned these eleven events to be the decays of $$^{264}$$Hs. We found different decay-chain events of $$^{264}$$Hs from a previous report. One is a long-lived $$alpha$$-decay of $$^{260}$$Sg with 180$$^{150}_{-60}$$ms of half-life. Another is a long-lived $$alpha$$-decay of $$^{256}$$Rf with 10.4$$^{8.4}_{-3.2}$$s of half-life. For $$^{260}$$Sg and $$^{256}$$Rf, the decay of such a long-lived state have not been reported. These are the first observations of isomerism in $$^{260}$$Sg and $$^{256}$$Rf.

Journal Articles

Attempt to produce the 3rd chain of $$^{278}$$113

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.

RIKEN Accelerator Progress Report, Vol.42, P. 15, 2009/00

In 2003-2007, we had performed an experiment to synthesize an element 113 by a $$^{209}$$Bi$$+$$ $$^{70}$$Zn reaction using a gas-filled recoil ion separator (GARIS) at RIKEN Nishina-Center. In a total of 241 days of net irradiation time experiment, two decay chains were observed and assigned from an isotope $$^{278}$$113. The cross section of the $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113 reaction was determined to be 31$$^{+40}_{-20}$$ fb at that time. In order to increase the statistics of the decay property, we continued to produce more decay chains. The experiment was carried out from January 7 to March 31, 2008. The experimental conditions were identical to those used in the previous experiment. $$^{70}$$Zn ion beam of 353 MeV was extracted from RILAC. The net irradiation time was 83 days and the total dose of $$^{70}$$Zn was 2.28$$times10^{19}$$. In the present expriment any candidate of $$^{278}$$113 was not observed. Then combining the results of the present and previous experiments, the production cross section of $$^{278}$$113 was determined to be 22$$^{+29}_{-19}$$ fb.

JAEA Reports

Construction, management and operation on advanced volume reduction facilities

Higuchi, Hidekazu; Osugi, Takeshi; Nakashio, Nobuyuki; Momma, Toshiyuki; Tohei, Toshio; Ishikawa, Joji; Iseda, Hirokatsu; Mitsuda, Motoyuki; Ishihara, Keisuke; Sudo, Tomoyuki; et al.

JAEA-Technology 2007-038, 189 Pages, 2007/07

JAEA-Technology-2007-038-01.pdf:15.13MB
JAEA-Technology-2007-038-02.pdf:38.95MB
JAEA-Technology-2007-038-03.pdf:48.42MB
JAEA-Technology-2007-038-04.pdf:20.53MB
JAEA-Technology-2007-038-05.pdf:10.44MB

The Advanced Volume Reduction Facilities (AVRF) is constructed to manufacture the waste packages of radioactive waste for disposal in the Nuclear Science Research Institute of the Japan Atomic Energy Agency. The AVRF is constituted from two facilities. The one is the Waste Size Reduction and Storage Facility (WSRSF) which is for reducing waste size, sorting into each material and storing the waste package. The other is the Waste Volume Reduction Facility (WVRF) which is for manufacturing the waste package by volume reducing treatment and stabilizing treatment. WVRF has an induction melting furnace, a plasma melting furnace, an incinerator, and a super compactor for treatment. In this report, we summarized about the basic concept of constructing AVRF, the constitution of facilities, the specifications of machineries and the state of trial operation until March of 2006.

Journal Articles

Experiment on synthesis of an isotope $$^{277}$$112 by $$^{208}$$Pb + $$^{70}$$Zn reaction

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.

Journal of the Physical Society of Japan, 76(4), p.043201_1 - 043201_5, 2007/04

 Times Cited Count:151 Percentile:95.96(Physics, Multidisciplinary)

The production and decay of $$^{277}$$112 has been investigated using a gas-filled recoil ion separator in irradiations of $$^{208}$$Pb targets with $$^{70}$$Zn beam at 349.5 MeV. We have observed two $$alpha$$-decay chains that can be assigned to subsequent decays from $$^{277}$$112 produced in the 208 Pb($$^{70}$$Zn,n) reaction. After emitting four consecutive $$alpha$$-particles, the both chains ended by spontaneous fission decays of $$^{261}$$Rf and decay energies and decay times of the both chains obtained in the present work agree well with those reported by a group at Gesellschaft f$"u$r Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of $$^{277}$$112 and its $$alpha$$-decay products $$^{273}$$Ds reported previously.

Journal Articles

Observation of second decay chain from $$^{278}$$113

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kikunaga, Hidetoshi*; et al.

Journal of the Physical Society of Japan, 76(4), p.045001_1 - 045001_2, 2007/04

 Times Cited Count:199 Percentile:97.42(Physics, Multidisciplinary)

The production and decay of $$^{278}$$113 has been investigated using a gas-filled recoil ion separator in irradiations of $$^{209}$$Bi targets with $$^{70}$$Zn beam at 353 MeV. We have observed one $$alpha$$-decay chain that can be assigned to subsequent decays from $$^{278}$$113 produced in the $$^{209}$$Bi($$^{70}$$Zn,n) reaction. After emitting four consecutive $$alpha$$-particles, the both chains ended by spontaneous fission decays of $$^{262}$$Db and decay energies and decay times of the both chains obtained in the present work agree well with those reported by our group in 2004. The present result gives the first clear confirmation of the discovery of $$^{278}$$113 and its $$alpha$$-decay products $$^{274}$$Rg reported previously.

Journal Articles

Experiments on synthesis of the heaviest element at RIKEN

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Kikunaga, Hidetoshi*; et al.

AIP Conference Proceedings 891, p.3 - 9, 2007/03

A series of experiments studying the productions and their decays of the heaviest elements have been performed by using a gas-filled recoil separator GARIS at RIKEN. Results on the isotope of the 112th element, $$^{277}$$112, and on that of the 113th element, $$^{278}$$113, are reviewed. Two decay chains which are assigned to be ones originating from the isotope $$^{277}$$112 were observed in the $$^{208}$$Pb($$^{70}$$Zn, n) reaction. The results provide a confirmation of the production and decay of the isotope $$^{277}$$112 reported by a research group at GSI, Germany, produced via the same reaction by using a velocity filter. Two decay chains, both consisted of four consecutive alpha decays followed by a spontaneous fission, were observed also in the reaction $$^{209}$$Bi($$^{70}$$Zn, n). Those are assigned to be the convincing candidate events of the isotope of the 113th element, $$^{278}$$113, and its daughter nuclei. $$^{274}$$Rg, $$^{270}$$Mt, $$^{266}$$Bh, and $$^{262}$$Db.

Journal Articles

Measurement of the spin and magnetic moment of $$^{23}$$Al

Ozawa, Akira*; Matsuta, Kensaku*; Nagatomo, Takashi*; Mihara, Mototsugu*; Yamada, Kazunari*; Yamaguchi, Takayuki*; Otsubo, Takashi*; Momota, Sadao*; Izumikawa, Takuji*; Sumikama, Toshiyuki*; et al.

Physical Review C, 74(2), p.021301_1 - 021301_4, 2006/08

 Times Cited Count:43 Percentile:89.18(Physics, Nuclear)

no abstracts in English

Journal Articles

Experiment on the synthesis of element 113 in the reaction $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Koura, Hiroyuki; et al.

Journal of the Physical Society of Japan, 73(10), p.2593 - 2596, 2004/10

 Times Cited Count:487 Percentile:99.22(Physics, Multidisciplinary)

The isotope of the 113th element, $$^{278}$$113, and its daughter nuclei, $$^{274}$$111 and $$^{270}$$Mt, were obserbed, for the first time, in the $$^{209}$$Bi + $$^{70}$$Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.6$$times$$10$$^{19}$$. The production cross section of $$^{278}$$113 is deduced to be $$57^{+154}_{-47}$$ fb ($$10^{-39}$$ cm$$^2$$).

Oral presentation

Development of the high time resolution TOF detector for proton

Sato, Hiroki; Imai, Nobuaki*; Ishiyama, Hironobu*; Ozawa, Akira*; Jeong, S.-C.*; Nishio, Katsuhisa; Hashimoto, Takashi*; Hirayama, Yoshikazu*; Makii, Hiroyuki*; Mitsuoka, Shinichi; et al.

no journal, , 

no abstracts in English

Oral presentation

Productions and decay properties of $$^{264,265}$$Hs

Sato, Nozomi; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

In this work, the production and decay properties of $$^{264,265}$$Hs produced in the $$^{208}$$Pb($$^{58}$$Fe, $$xn$$) [$$x = 1,2$$] and $$^{207}$$Pb($$^{58}$$Fe, $$n$$) reactions were investigated. The experiment was performed at the RILAC facility in RIKEN. The evaporation residues (ERs) were separated from the primary beam with the gas-filled recoil ion separator, GARIS. In the focal plane of GARIS the products were implanted into a position-sensitive Si detector for measuring the arrival of ERs and subsequent $$alpha$$-decays or spontaneous fission from ERs. We have measured production cross-sections of $$^{264,265}$$Hs in the $$^{58}$$Fe + $$^{208}$$Pb reaction at several bombarding energies. For the $$^{208}$$Pb($$^{58}$$Fe, $$n$$)$$^{265}$$Hs reaction, the cross-section maximum of ($$51^{+46}_{-29}$$) pb was obtained at the bombarding energy of 220.5 MeV at the middle of the target. For even-even nucleus $$^{264}$$Hs, we have also observed accurate decay data with good statistics.

27 (Records 1-20 displayed on this page)