The reactions 2H(40Ar, n)41K and 2H(40Ar, p)40Ar and electromagnetic decays of low-lying states in 41K and 41Ar

doi:10.1016/0375-9474(77)90580-2

Nuclear Physics A

Volume 279, Issue 3, 4 April 1977, Pages 463-473

https://doi.org/10.1016/0375-9474(77)90580-2 Get rights and content

Abstract

The γ-decay of states in ⁴¹K and ⁴¹Ar populated in the reactions ²H(⁴⁰Ar, n)⁴¹K and ²H(⁴⁰Ar, p)⁴¹Ar has been investigated at a bombarding energy of 56 MeV. Using the Doppler shift attenuation method and three different stopping materials, mean lifetimes were determined for the states in ⁴¹K at 980 keV (0.5±0.2 ps), 1560 keV (0.6_−0.2^+0.3ps), 1698 keV (0.1_−0.1^+0.2ps), 2144 keV (0.8_−0.2^+0.3ps) and in ⁴¹Ar at 1354 keV (0.664_−0.08^+0.09ps). Shell-model calculations have been performed for the positive parity states in ⁴¹K using a model space of a proton hole in the $1 d_{32}$ and $2 s_{12}$ orbits and two neutrons in the $1 f_{72}$ orbit. The resulting excitation energies and electromagnetic properties of the low-lying states are in good agreement with experiment. An empirical value for a [Y₂s]₁ contribution in the effective M1 operator is obtained.

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Nuclear Data Sheets for A = 41
2016, Nuclear Data Sheets
Available information pertaining to the nuclear structure of all nuclei with mass numbers A=41 ranging from Al (Z=13) to Ti (Z=22) are presented. The experimental reaction and decay data are evaluated and any inconsistencies or discrepancies are noted. The adopted values for various level properties (such as the spin, parity and and halflife) and gamma properties (energy, intensity and multipole character) are given.
Since the prior evaluation several new measurements have expanded our knowledge of A=41 nuclides. The half-life of the ground state of ⁴¹Si has been determined and a single excited state identified. Excited levels in ⁴¹P have been observed for the first time. In ⁴¹Cl, seven new excited states have been identified in deep inelastic and heavy ion transfer reactions. Half-lifes for four states in ⁴¹Ar have been updated and additional levels with gammas have been included from a new measurement using the multiple ion transfer reaction. In ⁴¹Ca via charge-exchange reaction measurements, several new excited states were observed. A number of new resonances in ⁴¹K have been identified via the (p,γ) reaction.
There remains a significant discrepancy in the half-life of the first excited state (980 keV) in ⁴¹K, with measurements differing by more than an order of magnitude. Transfer reactions suggest that this M1 transition should be l-forbidden, however, several measurements yield a lifetime which suggests a sizable M1 strength. Further measurements to resolve the current conflicts would be beneficial.
Nuclear data sheets for A = 41
2001, Nuclear Data Sheets
Nuclear spectroscopic information for the known nuclides of mass 41 (Al,Si,P,S,Cl,Ar,K,Ca,Sc,Ti) has been evaluated. The principal sources of the adopted levels presented are Endt's evaluations (1990En08, 1978En02). The data sets for reactions and decays, including all available gamma--ray data, are based mostly on the original literature. There are no data available for the excited states in 41 Al, 41 Si, 41 P, 41 Cl and 41 Ti.
Energy levels of A = 21-44 nuclei (VII)
1990, Nuclear Physics, Section A
The experimentally determined properties of A = 21–44 nuclides are complied and evaluated with special emphasis on nuclear spectroscopy.
Separate tables for each of the nuclides reviewed present the available information about the following properties (in this order):
- •
  - excitation energies E_x,
- •
  - γ-ray branching ratios b(γ),
- •
  - γ-ray mixing ratios σ,
- •
  - lifetimes γ_m or widths Λ,
- •
  - neutron, proton, or α-particle resonances,
- •
  - partial widths,
- •
  - single-nucleon transfer reactions,
- •
  - beta-decay,
- •
  - arguments for spin and parity (J^π) and isospin (T) assignments.
For each nuclide a master table summarizing the “best” or adopted values for E_x, J^π; T and τ_m or Λ precedes the auxiliary tables listed above.
The review of each A-chain concludes with a discussion of isospin multiplets.
Figures are presented of the level schemes of all nuclei and, for each A-chain, an overview of the relative energies of the ground states and lowest analogue states of all nuclei in the chain.
Spectroscopy of 41K by thermal neutron capture in 40K
1984, Nuclear Physics, Section A
The γ-ray spectrum emitted after thermal neutron capture in ⁴⁰K has been studied at the ILL high flux reactor with curved crystal Bragg, pair and Ge(Li) spectometers. 585 transitions were assigned to the reaction ⁴⁰K(n, γ)⁴¹K and 490 of them were placed into a ⁴¹K level scheme; 68 new states are proposed. On the basis of γ-ray branches to states with established spin and parity, many new spin-parity assignments were made. The level energies up to 4 MeV were measured with a precision of 8–50 eV relative to the 411.8 keV ¹⁹⁸Au standard, those above 4 MeV with a precision of 50–100 eV. The spin of the capture state was found to be $I = 72$ ; the neutron binding energy was determined to E_B = 10095.25(10) keV. The level density of $I^{π} = 52^{±}, 72^{±}, 92^{±}$ states was analyzed in terms of the constant-temperature Fermi gas model. It was shown that in this spin window the level scheme is almost complete up to an excitation energy of 5 MeV.
Electroexcitation of the first excited states in 39K and 41K
1981, Nuclear Physics, Section A
The mixed E2/M1 transitions from the $32^{+}$ ground states to the first excited $case1 2^{+}$ states in ³⁹K. and ⁴¹K were studied by low momentum transfer inelastic electron scattering. The E2 contribution dominates the cross section and B(E2)↑ values for ³⁹K of 18.9 ± 1.8 e² · fm⁴ and for ⁴¹K of 23.9 ± 4.2 e² · fm⁴ were obtained. Together with the measured lifetimes of these states B(M1)↑ values for the $l- forbidden d 32 - s 12$ transition are deduced to be 0.015 ± 0.006 μ_K² in ³⁹K. and 0.067 ± 0.006 μ_K² in ⁴¹K.
Energy levels of A = 21-44 nuclei (VI)
1978, Nuclear Physics, Section A
The experimentally determined properties of the A = 21–44 nuclei are compiled and evaluated, special emphasis being given to nuclear structure.
Separate tables for each of the nuclides reviewed give all available information about the following properties in this order: - excitation energies (E_x),
1. •
  - γ-ray branching ratios,
2. •
  - γ-ray mixing ratios (δ),
3. •
  - lifetimes (τ_m) or widths (Λ),
4. •
  - spin and parity (J^π) and isospin (T) assignments, and
5. •
  - any other data, on single-particle transfer, resonance levels, etc.
The “best” (or adopted) values for E_x, τ_m or Λ, J^π and T are summarized in a master table.
The review of each A-chain concludes with - a discussion of isospin multiplets,
1. •
  - a few remarks about the experimental situation, and
2. •
  - a compilation of references to relevant theoretical papers.

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^☆: Supported in part by Gesellschaft für Schwerionenforschung, 61 Darmstadt, Germany.

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Nuclear Physics A

Abstract

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Cited by (14)

Nuclear Data Sheets for A = 41

Nuclear data sheets for A = 41

Energy levels of A = 21-44 nuclei (VII)

Spectroscopy of <sup>41</sup>K by thermal neutron capture in <sup>40</sup>K

Electroexcitation of the first excited states in <sup>39</sup>K and <sup>41</sup>K

Energy levels of A = 21-44 nuclei (VI)

The reactions 2H(40Ar, n)41K and 2H(40Ar, p)40Ar and electromagnetic decays of low-lying states in 41K and 41Ar☆

Abstract

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Nucl. Phys.

Phys. Lett.

Nucl. Phys.

Nucl. Phys.

Phys. Lett.

Nucl. Phys.

Nucl. Data Tables

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Nucl. Phys.

The reactions ²H(⁴⁰Ar, n)⁴¹K and ²H(⁴⁰Ar, p)⁴⁰Ar and electromagnetic decays of low-lying states in ⁴¹K and ⁴¹Ar☆