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Mach, Henryk
Alternative names
Publications (10 of 44) Show all publications
Mach, H., Korgul, A., Gorska, M., Grawe, H., Matea, I., Stanoiu, M., . . . Tarasov, O. (2017). Ultrafast-timing lifetime measurements in Ru-94 and Pd-96: Breakdown of the seniority scheme in N=50 isotones. PHYSICAL REVIEW C, 95(1), Article ID 014313.
Open this publication in new window or tab >>Ultrafast-timing lifetime measurements in Ru-94 and Pd-96: Breakdown of the seniority scheme in N=50 isotones
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2017 (English)In: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 95, no 1, article id 014313Article in journal (Refereed) Published
Abstract [en]

The advanced time-delayed gamma gamma(t) method has been applied to determine half-lives of low-lying states in the N = 50 isotones Ru-94 and Pd-96. The inferred experimental E2 strengths for the 4(+) -> 2(+) transitions in the two nuclei show a dramatic deviation with respect to the shell model predictions in the (f(5/2), p, g(9/2)) proton hole space in Sn-100. The anomalous behavior can be ascribed to a breakdown of the seniority quantum number in the pi g(9/2)(n) configuration due to particle-hole excitations across the N = Z = 50 shell as confirmed by large-scale shell model calculations.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-315813 (URN)10.1103/PhysRevC.95.014313 (DOI)000391860300002 ()
Funder
Swedish Research CouncilEU, European Research Council, HPRI-CT 1999-00019
Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2017-02-22Bibliographically approved
Isakov, V., Erokhina, K., Mach, H., Fogelberg, B., Korgul, A., Mezilev, K. & Ramström, E. (2007). Isomeric and two-quasiparticle states in the neutron-excess odd-odd nucleus 134Sb. Physics of Atomic Nuclei, 70(5), 818-826
Open this publication in new window or tab >>Isomeric and two-quasiparticle states in the neutron-excess odd-odd nucleus 134Sb
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2007 (English)In: Physics of Atomic Nuclei, ISSN 1063-7788, E-ISSN 1562-692X, Vol. 70, no 5, p. 818-826Article in journal (Refereed) Published
Abstract [en]

Detailed theoretical calculations of the properties of the neutron-excess odd–odd nucleus134    Sb are performed by using different theoretical approaches. A comprehensive comparison with the recentexperimental data is performed; this comparison suggests the presence of isomeric states among the low-lying levels of this nucleus. These states are the twins of the corresponding levels of the odd–odd nucleus210    Bi that is situated near the stability line. The obtained results manifest the similarity of nuclear structurein the region of the “remote” doubly magic nucleus 132 Sn and in the region of the classical stable doublymagic nucleus 208 Pb.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16942 (URN)10.1134/S1063778807050031 (DOI)000247212100003 ()
Available from: 2008-06-13 Created: 2008-06-13 Last updated: 2017-12-08Bibliographically approved
Fogelberg, B., Mezilev, K., Isakov, V., Erokhina, K., Mach, H., Ramström, E. & Gausemel, H. (2007). Neutron separation energies at N=83 and the isomer position in 136I. Physical Review C. Nuclear Physics, 75(5), 054308
Open this publication in new window or tab >>Neutron separation energies at N=83 and the isomer position in 136I
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2007 (English)In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 75, no 5, p. 054308-Article in journal (Refereed) Published
Abstract [en]

New experimental total β-decay energies of 135,136Te and of the two isomers of 136I have been obtained, giving much improved accuracy for the nuclear masses of these nuclides. The neutron separation energies at N=83 were deduced and are compared to recent theoretical and systematic predictions. The new results resolve the problem with the excitation energy of the isomeric state of 136I. Theoretical calculations of the isomer splitting of 136I are in good agreement with the new data.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16943 (URN)10.1103/PhysRevC.75.054308 (DOI)000246891100018 ()
Available from: 2008-06-13 Created: 2008-06-13 Last updated: 2017-12-08Bibliographically approved
Korgul, A., Mach, H., Birger, F. & Sawicka, M. (2007). On the unusual properties of the 282 keV state in 135Sb. European Physical Journal A, 32(1), 25-29
Open this publication in new window or tab >>On the unusual properties of the 282 keV state in 135Sb
2007 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 32, no 1, p. 25-29Article in journal (Refereed) Published
Abstract [en]

Recently the first excited state in 135Sb has been observed at the unexpectedly low excitation energy of only 282keV and interpreted as mainly d 5/2 proton coupled to the 134Sn core. Based on theoretical considerations it was suggested that its low excitation energy is related to a relative shift of the proton d 5/2 and g 7/2 orbits induced by the neutron excess. We have measured the lifetime of the 282keV state by the advanced time-delayed βγγ(t) method. The measured half-life, T 1/2 = 6.1(4)ns, yields exceptionally low limits of B(M1;5/21 +→7/21 +)≤3.0×10-4 μ 2 N and B(E2;5/21 +→7/21 +)≤54e 2 fm 4. These strongly hindered M1 and slow E2 transition rates are similar to those for the transition de-populating the first excited state at 405keV in 211Bi. Results of shell model calculations with realistic interactions are presented. The M1 decay rate was found to be extremely sensistive both to the wave function and to the M1 effective operator.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16994 (URN)10.1140/epja/i2007-10363-0 (DOI)000246738700005 ()
Available from: 2008-06-12 Created: 2008-06-12 Last updated: 2017-12-08Bibliographically approved
Boutami, R., Mach, H. & Tengblad, O. (2007). Structure of Ac-231: Measurements of level half-lives. European Physical Journal - Special Topics, 150(1), 87-88
Open this publication in new window or tab >>Structure of Ac-231: Measurements of level half-lives
2007 (English)In: European Physical Journal - Special Topics, ISSN 1951-6355, Vol. 150, no 1, p. 87-88Article in journal (Refereed) Published
Abstract [en]

There is lack of knowledge of the structure of the Ac-231 nucleus located in the upper border of the island of octupole deformation centered around A = 225. We have populated the excited states in Ac-231 by beta-decay from the parent Ra-231 produced at ISOLDE, CERN. The low-energy structure of Ac-231 has been investigated by means of gamma, conversion electrons, gamma-gamma and gamma-e(-) spectroscopy. We report here in the precise determination in Ac-231 of the half-life of the most intensively populated states by the Advanced Time Delayed beta beta gamma(t) technique.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-17012 (URN)10.1140/epjst/e2007-00273-9 (DOI)000251601600025 ()
Available from: 2008-06-13 Created: 2008-06-13 Last updated: 2011-04-08Bibliographically approved
Mach, H., Fraile, L., Arndt, O., Blazhev, A., Boelaert, N., Borge, M., . . . Walters, W. (2007). The single-particle and collective features in the nuclei just above Sn-132. Acta Physica Polonica B, 38(4), 1213-1218
Open this publication in new window or tab >>The single-particle and collective features in the nuclei just above Sn-132
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2007 (English)In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 38, no 4, p. 1213-1218Article in journal (Refereed) Published
Abstract [en]

The Advanced Time Delayed method has been used to measure the lifetimes of excited states in the exotic nuclei Sb-134, Sb-135 and Te-136 populated in the beta decay of Sn-134, Sn-135 and Sn-136, respectively. High purity Sn beams were extracted at the ISOLDE separator using a novel production technique utilizing the molecular SnS+ beams to isolate Sn from contaminating other fission products. Among the new results we have identified the 1/2(+) state in Sb-135 and its E2 transition to the lower-lying 5/2(+) state was found to be surprisingly collective. This measurement represents also one of the first applications of the LaBr3 scintillator to ultra fast timing.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-16945 (URN)000246400400013 ()
Available from: 2008-06-13 Created: 2008-06-13 Last updated: 2017-12-08
Mach, H. (2006). Beta decay half-life of 231Ra. Physica Scripta, 2006(T125), 180-1
Open this publication in new window or tab >>Beta decay half-life of 231Ra
2006 (English)In: Physica Scripta, Vol. 2006, no T125, p. 180-1Article in journal (Refereed) Published
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-23360 (URN)
Available from: 2007-01-28 Created: 2007-01-28 Last updated: 2011-01-11
Mach, H. & Fogelberg, B. (2006). Nuclear structure of 229Th. Physical Review C: Nuclear Physics, 73(4), 44326-1
Open this publication in new window or tab >>Nuclear structure of 229Th
2006 (English)In: Physical Review C: Nuclear Physics, Vol. 73, no 4, p. 44326-1Article in journal (Refereed) Published
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-82994 (URN)
Available from: 2007-01-29 Created: 2007-01-29 Last updated: 2011-01-11
Mach, H. & Fogelberg, B. (2005). Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei. Journal of Physics G: Nuclear and Particle Physics, 31(10), S1421-6
Open this publication in new window or tab >>Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei
2005 (English)In: Journal of Physics G: Nuclear and Particle Physics, Vol. 31, no 10, p. S1421-6Article in journal (Refereed) Published
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-82988 (URN)
Available from: 2007-01-29 Created: 2007-01-29 Last updated: 2011-01-12
Mach, H. & Fogelberg, B. (2005). ISOLDE beams of neutron-rich zinc isotopes: yields, release, decay spectroscopy. In: AIP Conference Proceedings (pp. 315-23).
Open this publication in new window or tab >>ISOLDE beams of neutron-rich zinc isotopes: yields, release, decay spectroscopy
2005 (English)In: AIP Conference Proceedings, 2005, p. 315-23Conference paper, Published paper (Other scientific)
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-82995 (URN)
Available from: 2007-01-29 Created: 2007-01-29
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