Levels and gamma transitions of<sup>40</sup>K studied by neutron capture

Egidy, T. von; Daniel, H.; Hungerford, P.; Schmidt, Hartwig; Lieb, Klaus; Krusche, B.; Kerr, S. A.; Barreau, G.; Börner, H. G.; Brissot, R.; Hofmeyr, C.; Rascher, R.

doi:10.1088/0305-4616/10/2/013

Cited by 22 publications

(22 citation statements)

References 18 publications

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“…Detailed measurements of the relative γ-ray intensity depopulating the capture state in 40 K were done by von Egidy et al [3] on a natural potassium target, and by Krusche et al [4,5] who measured relative γ-ray intensities depopulating the capture states in 41,42 K using enriched targets. For each isotope nearly 100% of the total γ-ray cross section feeding the ground state was observed.…”

Section: Resultsmentioning

confidence: 99%

“…Weak potassium transition cross sections were calibrated by their relative intensities with respect to the 770.3-keV γ-ray. The γ-rays were assigned to level schemes for the three potassium isotopes 40 K, 41 K, and 42 K on the basis of energy and intensity by comparison with data from the ENSDF [14] file and with the potassium neutron capture data of von Egidy et al [3] and Krusche et al [4,5]. Isotopic γ-ray cross sections were determined assuming the normal potassium isotopic abundances [15].…”

Section: Methodsmentioning

confidence: 99%

“…Isotopic γ-ray cross sections were determined assuming the normal potassium isotopic abundances [15]. The original von Egidy et al [3] and Krusche et al [4,5] data were normalized assuming the total observed intensity feeding the GS is 100. Weak transitions not observed in our work but seen in the earlier experiments were renormalized by a least-squares fit to the Budapest cross section data and used to complete the (n,γ) level schemes.…”

Section: Methodsmentioning

confidence: 99%

“…The relatively low level density for the potassium isotopes allows the observation of a significant portion of their decay schemes [3][4][5] including the ground-state transitions from levels up to near the neutron separation energy so this correction is expected to be small. We compared the intensities of individual transitions simulated by the DICEBOX code with experiment assuming that all transitions with intensities I higher than the detection threshold I thr were observed and transitions with I < I thr were not observed.…”

Section: Corrections To the Observed Cross Section σ0mentioning

confidence: 99%

“…The cross sections were internally standardized using a stoichiometric KCl target with well known 35 Cl(n,γ) γ-ray cross sections [1,2]. These data were combined with γ-ray intensities from von Egidy et al [3] and Krusche et al [4,5] to generate nearly complete capture γ-ray level schemes. Total radiative neutron cross sections were deduced from the total γ-ray cross section feeding the ground state, σ0 = Σσγ (GS) after correction for unobserved statistical γ-ray feeding from levels near the neutron capture energy.…”

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confidence: 99%

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Thermal neutron capture cross sections of the potassium isotopes

et al. 2013

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Precise thermal neutron capture γ-ray cross sections σγ for 39,40,41 K were measured on a natural potassium target with the guided neutron beam at the Budapest Reactor. The cross sections were internally standardized using a stoichiometric KCl target with well known 35 Cl(n,γ) γ-ray cross sections [1,2]. These data were combined with γ-ray intensities from von Egidy et al [3] and Krusche et al [4,5] to generate nearly complete capture γ-ray level schemes. Total radiative neutron cross sections were deduced from the total γ-ray cross section feeding the ground state, σ0 = Σσγ (GS) after correction for unobserved statistical γ-ray feeding from levels near the neutron capture energy. The corrections were performed with Monte Carlo simulations of the potassium thermal neutron capture decay schemes using the computer code DICEBOX where the simulated populations of low-lying levels are normalized to the measured cross section depopulating those levels. Comparisons of the simulated and experimental level feeding intensities have led to proposed new spins and parities for selected levels in the potassium isotopes where direct reactions are not a significant contribution. We determined the total radiative neutron cross sections σ0( 39 K)=2.28±0.04 b, σ0( 40 K)=90±7 b, and σ0( 41 K)=1.62±0.03 b from the prompt γ-ray data and the γ-ray transition probability Pγ (1524.66)=0.164(4) in the β − decay of 42 K in a low-background counting experiment.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Corrections To the Observed Cross Section σ0mentioning

confidence: 99%

mentioning

confidence: 99%

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Thermal neutron capture cross sections of the potassium isotopes

et al. 2013

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Thermal neutron capture?-ray spectroscopy of59Ni and61Ni

Harder

Michaelsen

Lieb

et al. 1993

Z. Physik A - Hadrons and Nuclei

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Abstract. The 7-radiation emitted after thermal neutron capture in isotopically enriched 58Ni and 6~ was measured at the ILL high flux reactor by means of Ge/NaI detectors operated in Compton suppression and pair spectrometer mode. The neutron binding energies were determined as B.(59Ni) = 8999.15(23) keV and Bn(61Ni) = 7820.07(20) keV; some 95% of the total y-ray fluxes through s9,61Ni were assigned. The y-ray strength functions of the primary transitions and the level densities are discussed. 21.10.Ma; 23.20.Lv; 25.40.Lw; 27.50.+e PACS: MotivationThe 7-ray decay of the capture state(s) populated in thermal neutron capture reactions is considered to be a nonselective process and thus enables one to establish "complete" level schemes up to about half the neutron binding energy B, and within the spin window bound by s-wave capture and primary dipole transitions. Previous detailed studies of light and medium nuclei [1,2] have shown that the assignment of new states is essentially limited by the increasing level density and decreasing phase space of primary transitions, for given capture crosssections and spectrometer resolution and efficiency.Previous (n, ~) studies in the even-mass nickel targets [3] have shown deviations from this behaviour insofar as the primary spectra are dominated by very few strong transitions to low-lying negative-parity states which account for some 70%-90% of the primary flux. This direct mechanism thus dominates the capture process and leaves correspondingly little flux to higher excited states; this flux was not fully resolved up to now. With the high neutron flux available at the ILL reactor and a high resolution pair spectrometer we hoped to be able to identify the missing portions of the primary spectra Supported by Deutsches BMFT of the 5s'6~ 7) reactions, to identify new excited states and make spin-parity assignments. This information, together with the results from charged-particle induced reactions then should allow us to derive level densities and ~-ray strength functions in the semi-magic Z=28 nickel isotopes, and compare them to findings for N ~_ 20, 28 and 50 neutron magic nuclei [4][5][6][7][8][9].This present work complements our previous studies of the 6~Ni(n, ~)63Ni and 6ZNi(2 n, 7)64Ni reactions [10] and the GRID lifetime measurements in 59'61Ni by U1-big et al. [11]. In this latter work, assumptions concerning the feeding mechanism of several excited states had to be inferred which now can be checked with the present data. Ulbig and co-authors [11,12] also performed extensive shell model calculations of the negative parity states in 59Ni. Experimental procedureThe experimental procedure followed the method applied in our previous neutron capture studies on 31p, s~ 86'87'aasr and 62Ni targets [5-8, 10, 13] where further details of the experimental set-up and data analysis are given. First the 58Ni target, consisting of ca. 130mg of metallic powder (isotopical enrichment 99.8%), was exposed to a thermal neutron flux of 5.5.1014 neutrons/cm 2 s near the core of the ILL h...

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Low-lying states and degree of chaoticity of40K in IBFFM

Seyfarth

Brant

Göttel

et al. 1988

Z. Physik A - Atomic Nuclei

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The results of a 7-~ angular correlation and a low energy 7-ray singles measurement using thermal neutron capture in 39K are presented. The properties of low-lying levels of 4~ are interpreted in a comparison of the experimental data with the InteractingBoson-Fermion-Fermion Model (IBFFM). The level fluctuation properties of the IBFFM spectrum are analysed and a sizeable deviation from chaoticity is found.

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Levels and gamma transitions of⁴⁰K studied by neutron capture

Cited by 22 publications

References 18 publications

Thermal neutron capture cross sections of the potassium isotopes

Thermal neutron capture cross sections of the potassium isotopes

Thermal neutron capture?-ray spectroscopy of59Ni and61Ni

Low-lying states and degree of chaoticity of40K in IBFFM

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Levels and gamma transitions of40K studied by neutron capture

Cited by 22 publications

References 18 publications

Thermal neutron capture cross sections of the potassium isotopes

Thermal neutron capture cross sections of the potassium isotopes

Thermal neutron capture?-ray spectroscopy of59Ni and61Ni

Low-lying states and degree of chaoticity of40K in IBFFM

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Levels and gamma transitions of⁴⁰K studied by neutron capture