Experimental upper limit for a γ branch from the<sup>236</sup>U shape isomer

Butler, P. A.; Daniel, Robert G.; Irving, A.D.; Morrison, T P; Nolan, P.; Metag, V.

doi:10.1088/0305-4616/6/9/012

Cited by 17 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because of the lower height of the inner barrier for low Z actinides (Nilsson, 1970), together with the augmentation of the height ,of the second barrier due to the presence of the muon in Is orbital , the back-decay gamma ray seemed to be the most feasible candidate for such a measurement. Some previous works (Russo et al 1974, Kaplan et al 1976, Fromm et al 1976, Butler et al 1980, as well as the present experiment, have concentrated on this measurement.…”

Section: Muod Induced Shape Isomersupporting

confidence: 52%

“…For 238Np shape isomer, no back-decay gamma ray was observed (Borggreen et al 1974), and in 236U contradictory results exist (Habs et al 1975;Bartsch et al 1978;Butler et al 1980).…”

Section: Ini'roducnonmentioning

confidence: 99%

“…A recent experiment (Butler et al ,1980) using 235U(d,p) 236U reaction to search for the gamma branch of such an isomer also failed to produce any positive result. In this sense our 236U experimental result is consistent with their negative finding.…”

mentioning

confidence: 95%

See 2 more Smart Citations

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Mireshghi¹

1982

View full text Add to dashboard Cite

We have searched for back-decay gainmaray~' from the shape isomeric'states in 23SU,' 236U,and 2J8U possibly excited iii muon r~diationiess tr~nsiiion. The energies ilrtd intensities of g~ rays foll~~ng muon atomi~ Ca.pt~re were measured as a function of time after muon stopping. Background was suppressed by requiring that the candidate gamma ray be followed by another gamma ray (It-capture gamma ray). The prompt gamma-ray spectra included the Umuonic x rays. The measured 23SU and 238U x-ray energies were in good agreement with previously reported results. The x-ray spectrum from 236U has not been previously reported. The '-236U spectrum is very similar to that of 238U, except that the K x-rays exhibit an isotope shift of approximately 20 kev, the 236U energies being higher.In the analysis of the delayed spectra of 236U and 238U using the GAMANL peak searching program, and with an effective lower-limit detection efficiency of .15% per stopping muon, no candidate gamma rays for the back decay transitions from the shape isomeric state were observed. However, a more sensitive hand a:nalysis of the "smoothed background-subtracted" spectra resulted in the identification of some delayed ganirriil activities close to or below the 0.15% level. Both nuclei would be produced by muon capture on ~.

show abstract

Section: Muod Induced Shape Isomersupporting

confidence: 52%

“…For 238Np shape isomer, no back-decay gamma ray was observed (Borggreen et al 1974), and in 236U contradictory results exist (Habs et al 1975;Bartsch et al 1978;Butler et al 1980).…”

Section: Ini'roducnonmentioning

confidence: 99%

See 1 more Smart Citation

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Mireshghi¹

1982

View full text Add to dashboard Cite

show abstract

“…When a secondary minimum is separated from the main minimum by a high barrier, in the extreme case a long-lived isomer, called shape isomer, can be formed [7]. Shape isomerism at spin zero, so far, has clearly been observed only in actinide nuclei -these isomers decay mainly by fission, and in two cases only, 236 U and 238 U, by very retarded γ-ray branches [8][9][10][11].The existence of shape isomers in lighter systems has been a matter of debate for a long time. Already in the 1980s, a study based on microscopic Hartree-Fock plus BCS calculations, in which a large number of nuclei was surveyed, identified ten isotopes in which a deformed 0 þ state is separated from a spherical structure by a significantly high barrier:…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Multifaceted Quadruplet of Low-Lying Spin-Zero States in Ni66 : Emergence of Shape Isomerism in Light Nuclei

Leoni¹,

Fornal²,

Mărginean³

et al. 2017

Phys. Rev. Lett.

View full text Add to dashboard Cite

þ states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 0 þ 4 to the spherical 2 þ 1 state, although overestimating its value. This result makes 66 Ni a unique nuclear system, apart from 236;238 U, in which a retarded γ transition from a 0 þ deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior. DOI: 10.1103/PhysRevLett.118.162502 The concept of potential energy surface (PES) is central in many areas of physics. Usually, the PES displays the potential energy of the system as a function of its geometry. As an example, the PES of a molecule expressed in such coordinates as bond length, valence angles, etc., can be used for finding the minimum energy shape or calculating chemical reaction rates [1]. The idea of potential energy surface in deformation space has also been widely applied to the nucleus at a given spin. For an even-even nucleus at spin 0, the lowest PES minimum corresponds to the ground state (g.s.), while there may exist additional (secondary) minima in which excited 0 þ states can reside: they can be interpreted as ground states of different shapes [2][3][4][5][6]. When a secondary minimum is separated from the main minimum by a high barrier, in the extreme case a long-lived isomer, called shape isomer, can be formed [7]. Shape isomerism at spin zero, so far, has clearly been observed only in actinide nuclei -these isomers decay mainly by fission, and in two cases only, 236 U and 238 U, by very retarded γ-ray branches [8][9][10][11].The existence of shape isomers in lighter systems has been a matter of debate for a long time. Already in the 1980s, a study based on microscopic Hartree-Fock plus BCS calculations, in which a large number of nuclei was surveyed, identified ten isotopes in which a deformed 0 þ state is separated from a spherical structure by a significantly high barrier:66 Ni and 68 Ni, 190;192 Pt, 206;208;210 Os, and 194;196;214

show abstract

The Investigation of Fission Isomers by Photonuclear Reactions

et al. 1982

View full text Add to dashboard Cite

Experimental upper limit for a γ branch from the²³⁶U shape isomer

Cited by 17 publications

References 11 publications

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Multifaceted Quadruplet of Low-Lying Spin-Zero States in Ni66 : Emergence of Shape Isomerism in Light Nuclei

The Investigation of Fission Isomers by Photonuclear Reactions

Contact Info

Product

Resources

About

Experimental upper limit for a γ branch from the236U shape isomer

Cited by 17 publications

References 11 publications

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Search for the gamma-branch of the shape isomers of separated U isotopes using muon for nuclide excitation

Multifaceted Quadruplet of Low-Lying Spin-Zero States in Ni66 : Emergence of Shape Isomerism in Light Nuclei

The Investigation of Fission Isomers by Photonuclear Reactions

Contact Info

Product

Resources

About

Experimental upper limit for a γ branch from the²³⁶U shape isomer