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Dive into the research topics where H. Kankaanpää is active.

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Featured researches published by H. Kankaanpää.


Nuclear Physics | 2001

Identification of excited states in 167Os and 168Os: shape coexistence at extreme neutron deficiency

D. T. Joss; S. L. King; R. D. Page; J. Simpson; A. Keenan; N. Amzal; T. Bäck; M. A. Bentley; B. Cederwall; J. F. C. Cocks; D. M. Cullen; P. T. Greenlees; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; H. Kettunen; P. Kuusiniemi; M. Leino; M. Muikku; A. Savelius; J. Uusitalo; S. J. Williams

Excited states in the very neutron-deficient isotopes Os-167 and Os-168 have been observed using the reaction Sn-112(Ni-58, 2pxn). The JUROSPHERE gamma -ray spectrometer array was used in conjuncti ...


Nuclear Physics | 1998

High-spin study of 119Xe

H. C. Scraggs; E. S. Paul; A. J. Boston; J. F. C. Cocks; D. M. Cullen; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; M. Muikku; P. J. Nolan; C. M. Parry; A. Savelius; R. Wadsworth; A.V. Afanasjev; I. Ragnarsson

Abstract High-spin states have been populated in 54 119 Xe via the 96 Mo( 27 Al,p3n) reaction at 133 MeV, using the Jurosphere γ-ray spectrometer to record triple γ-ray coincidences. The known level scheme has been significantly extended and several band crossings identified. In particular, the νh 11 2 yrast band has been extended to I π = ( 83 2 − ) and shows features which are consistent with those of smooth band termination at high spin. Theoretical results for 119 Xe at high spin are discussed within the framework of cranked Nilsson-Strutinsky calculations, together with results for 117 Xe.


Nuclear Physics | 1999

Coexistence of triaxial and prolate shapes in 171Ir

R A Bark; S. Törmänen; T. Bäck; B. Cederwall; S.W. Ødegård; J. F. C. Cocks; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; H. Kettunen; P. Kuusiniemi; M. Leino; M. Muikku; P. Rahkila; A. Savelius; M. Bergström; F. Ingebretsen; A. Maj; M Mattiuzzi; W. F. Mueller; L. L. Riedinger; T.R. Saitoh; P.O. Tjøm

Abstract Excited states in 171Ir have been observed for the first time. Gamma-rays were assigned to the nucleus by the recoil-decay tagging method. The ground-state band has a structure consistent with an h 11 2 proton coupled to a core of large triaxial deformation. At high spins, a bandcrossing occurs which is interpreted as a change in shape to a prolate deformation. Band-mixing calculations are performed for 171–175Ir. These show that shape-coexistence between triaxial and prolate states in these nuclei follows the same systematics found in their Pt and Os neighbours. The systematics are also compared with deformations calculated for 171–179Ir using the code “Ultimate Cranker”. Dipole bands were also observed, but tilted axis cranking calculations suggest that they are associated with a collective rotation.


AIP Conference Proceedings | 2005

Heavy Element Spectroscopy At JYFL

P. T. Greenlees; N. Amzal; J. E. Bastin; E. Bouchez; P. A. Butler; A. Chatillon; O. Dorvaux; S. Eeckhaudt; Kari J. Eskola; B. J. P. Gall; J. Gerl; T. Grahn; A. Görgen; N. J. Hammond; K. Hauschild; R.-D. Herzberg; F.‐P. Heßberger; R. D. Humphreys; A. Hürstel; D. Jenkins; G. D. Jones; Peter J. H. Jones; R. Julin; S. Juutinen; H. Kankaanpää; A. Keenan; H. Kettunen; F. Khalfallah; W. Korten; P. Kuusiniemi

A series of experiments to study the properties of transfermium nuclei have been performed at the Department of Physics of the University of Jyvaskyla. The experiments are carried out by a large group of collaborating institutes. These studies have been rendered possible by the coupling of various state‐of‐the‐art detector systems to the RITU gas‐filled recoil separator. In‐beam conversion‐electron and gamma‐ray measurements have been made using the SACRED silicon and JuroGam germanium‐detector arrays, respectively. The introduction of the GREAT spectrometer and TDR data acquisition system have greatly improved the quality of the data obtained at RITU. A brief overview of the instrumentation used and highlights from recent experiments are presented.


Nuclear Physics | 2000

High-spin study of neutron-deficient 114Xe

E. S. Paul; H. C. Scraggs; A. J. Boston; O. Dorvaux; P. T. Greenlees; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; H. Kettunen; M. Muikku; P. Nieminen; P. Rahkila; O. Stezowski

Abstract High-spin states have been populated in 114 54 Xe via the 58 Ni( 58 Ni, 2p) reaction at 210 MeV, using the Jurosphere γ -ray spectrometer to record γ -ray coincidences. The known level scheme has been significantly extended and includes two positive-parity and three negative-parity structures. At the highest spins, one of the negative-parity bands becomes yrast and shows the characteristics of a smoothly terminating band. Quadrupole moments for two of the bands at high spin have been estimated through a Doppler-broadened lineshape analysis; the terminating band has a reduced quadrupole moment implying that it is not far from full termination into a noncollective oblate state. Extracted B( E 1) strengths are discussed in terms of possible octupole collectivity.


Journal of Physics G | 2000

Isomeric state in the doubly odd 196At nucleus

M.B. Smith; R. Chapman; J.F.C. Cocks; K.M. Spohr; O. Dorvaux; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; H. Kettunen; P. Kuusiniemi; Y. Le Coz; M. Leino; D.J. Middleton; M. Muikku; P. Nieminen; P. Rahkila; A. Savelius

An excited isomeric state has been identified in the 196At nucleus using the recoil decay tagging technique. This is the first identification of an excited state in this neutron-deficient odd-odd nucleus. Several tentative prompt γ-rays have also been correlated with 196At α-decay, although it has not been possible to assign them to specific energy levels in 196At. The mean lifetime of the isomeric state has been measured as τ = 11±2 µs. The new level is compared with similar low-lying states in neighbouring nuclei and is de-excited by an E2 γ-ray transition, the large hindrance of which is not expected.


Nuclear Physics | 1999

Bandcrossings in 171Os

R A Bark; S Tormanen; T. Bäck; B. Cederwall; S.W. Ødegård; J. F. C. Cocks; K. Helariutta; P. M. Jones; R. Julin; S. Juutinen; H. Kankaanpää; H. Kettunen; P. Kuusiniemi; M. Leino; M. Muikku; P. Rahkila; A. Savelius

The nucleus Os-171 has been populated using the reaction Sn-116(Ni-58,2pn). Four new bands are identified, and the previously known bands are extended in spin, to a maximum of 53/2 (h) over bar. On ...


Frontiers of Nuclear Structure , AIP Conference Proceedings 656 | 2003

Gamma‐ray Spectroscopy Of Very Neutron‐Deficient Bi Isotopes

P. Nieminen; S. Juutinen; J. F. C. Cocks; O. Dorvaux; T. Enqvist; T. Grahn; P. T. Greenlees; K. Helariutta; P. M. Jones; R. Julin; H. Kankaanpää; A. Keenan; H. Kettunen; P. Kuusiniemi; M. E. Leino; A.-P. Leppänen; M. Muikku; J. Pakarinen; P. Rahkila; A. Savelius; J. Uusitalo; E. Bouchez; A. Hürstel; K. Hauschild; W. Korten; Y. Le Coz; M. Rejmund; Ch. Theisen; N. Amzal; A. N. Andreyev

Prompt and delayed γ rays from in 191,193Bi have been identified using the recoil‐decay tagging (RDT), isomer tagging, and recoil gating techniques, resulting in extensive level schemes for both nuclei. Excitation energies of the isomeric 13/2+ states have been established and rotational bands based on them have been observed. The nearly spherical 9/2− ground‐state bands appear to be crossed by more deformed low‐lying structures. TRS calculations have been performed and B(M1)/B(E2) ratios have been extracted for the observed strongly‐coupled bands. In 193Bi, a 3 μs isomer has been interpreted as a h9/2 proton coupled to the 12+ state of the 192Pb core.


NUCLEAR PHYSICS IN THE 21st CENTURY:International Nuclear Physics Conference INPC 2001 | 2002

Nuclear structure and formation mechanism of heavy shell-stabilized nuclei

P. Reiter; T. L. Khoo; A. Heinz; T. Lauritsen; C. J. Lister; D. Seweryniak; A. A. Sonzogni; I. Ahmad; P. Bhattacharyya; P. A. Butler; M. P. Carpenter; A. J. Chewter; J. A. Cizewski; C. N. Davids; J. P. Greene; P. T. Greenlees; K. Helariuta; R.-D. Herzberg; R. V. F. Janssens; G. D. Jones; R. Julin; H. Kankaanpää; H. Kettunen; H. Kuusiniemi; F. G. Kondev; M. Leino; S. Siem; J. Uusitalo; K. Vetter; I. Wiedenhöver

In a series of experiments, 48Ca induced cold fusion reactions on Pb targets were employed to populate states in 253,254No isotopes. The groundstate band of 254No is identified up to spin 20+. The deduced quadrupole deformation is β=0.27(2). Evidence for decays from a rotational band built on a 7/2[624] configuration was obtained in 253No. The initial angular momentum and excitation energy of 253,254No residues, after neutron emission, was determined. States up to spin 22 ℏ and excitation energy of E*=8.5 MeV were observed. The data provide direct information on the fission barrier at high spins Bf≥5 MeV, and on the shell-correction energy Eshellexp≥4.1 MeV.


Experimental nuclear physics in europe: Facing the next millennium | 2008

Excited states in the heavy nuclide 254No

H. Kankaanpää; M. E. Leino; R.-D. Herzberg; A. Chewter; F. P. Heßberger; Y. Le Coz; F. Becker; P. A. Butler; J. F. C. Cocks; O. Dorvaux; Kari J. Eskola; J. Gerl; P. T. Greenlees; K. Helariutta; M. Houry; G. D. Jones; Peter J. H. Jones; R. Julin; S. Juutinen; H. Kettunen; T. L. Khoo; A. Kleinböhl; W. Korten; P. Kuusiniemi; R. Lucas; M. Muikku; P. Nieminen; R. D. Page; P. Rahkila; P. Reiter

In-beam γ-ray spectroscopy of the excited states in the heavy nuclide 254No have been studied in the reaction 208Pb(48Ca,2n)254No. The techniques of recoil-gating and recoil-decay-tagging were needed due to the dominant fission background. Prompt γ-rays were detected with a Ge detector array, consisting of four clover detectors in close geometry, and a gas-filled recoil separator (RITU) was used for detecting recoils and their α-decays. The observed six γ-rays were associated with E2-transitions in the ground state rotational band of 254No. The value β2=0.27±0.03 was extracted for the quadrupole deformation from the extrapolated 2+ excitation energy.

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R. Julin

University of Jyväskylä

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K. Helariutta

University of Jyväskylä

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P. T. Greenlees

University of Jyväskylä

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M. Muikku

University of Jyväskylä

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P. Kuusiniemi

University of Jyväskylä

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M. Leino

University of Jyväskylä

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H. Kettunen

University of Jyväskylä

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P. M. Jones

University of Jyväskylä

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P. Rahkila

University of Jyväskylä

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S. Juutinen

University of Jyväskylä

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