Measurement of the total cross section for 235U and 238U photofission in the δ-resonance region

Ahrens, J.; Arends, J.; Bourgeois, P.; Carlos, P.; Fallou, J.L.; Floss, N.; Garganne, P.; Huthmacher, S.; Kneißl, U.; Mank, G.; Mecking, B. A.; Ries, Harald; Stenz, R.; Veyssière, A.

doi:10.1016/0370-2693(84)91701-5

Cited by 63 publications

(23 citation statements)

References 14 publications

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“…8 c); the full line is the result of the Monte Carlo calculation by Lepr~tre et al [5]. Experimental data are as follows: EJ, Bellini et al [23]; o, Bellini et al [4]; o, Lepr~tre et al [5]; o, Moretto et al [24]; o, Ivanov et al [7]; v, Ahrens et al [3]; a, Minarik and Novikov [20]; o, Bernabei et al [6]; m, Martins et al [8]; A, Tavares et al [9]; ..... , Arruda-Neto et al [25] 415 mean value of 16 • 2 rob, in good agreement with Monte Carlo calculations at energies up to 75 MeV (solid curve from [5]). For photon energies beyond ,-,60MeV, the result of the present calculation (dashed curve) agrees quite well with that reported in [5], although marked differences there exist at the lower energies.…”

Section: Results and Comparison With Experimental Datamentioning

confidence: 99%

“…Since a considerable number of measured photofission cross section data has been accumulated from bremsstrahlung- [18][19][20][21][22][23], electron- [24][25][26][27], and monochromatic photon-induced [3][4][5][6][7][8][9][10][11][12][13] fission experiments, we thought it worthwhile to perform a detailed analysis of these data by evaluating the fission cross section, ~r s, as a function of energy from the referred current photofission model, and to compare it with the experimental results. Two representative target nuclei have been thus selected for the purposes of the present analysis, namely 2~ and 238U.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of209Bi and238U photofission cross section in the quasi-deuteron region of photonuclear absorption

Tavares

Terranova

1992

Z. Physik A - Hadrons and Nuclei

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Abstract. An analysis of the photofission reactions in the quasi-deuteron energy range of photonuclear absorption (~30-140 MeV) has been performed for 2~ and 238U nuclei. Experimental cross section data available in the literature have been compared with calculated values obtained from a model in which the incoming photon is assumed to be absorbed by a neutron-proton pair (Levinger's quasi-deuteron photoabsorption), followed by a mechanism of evaporation-fission competition for the excited residual nuclei. The model has been shown to reproduce the main experimental features of 2~ and ~38U photofission cross section, although unexplained differences still remain in the case of 238U-fission by 30-50 MeV incident photons. 25.85.Jg PACS:

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Section: Results and Comparison With Experimental Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of209Bi and238U photofission cross section in the quasi-deuteron region of photonuclear absorption

Tavares

Terranova

1992

Z. Physik A - Hadrons and Nuclei

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“…3 we show the calculated results, solid, dashed and dot-dash lines, compared to experimental points from Ref. [19] for uranium and lead nuclei. The dash-dot line is obtained using a free pion propagator, in which case we observe that the isobar becomes too narrow to describe the width of the measured data, even with included smearing due to Fermi motion of the nucleons.…”

Section: Nuclear Photoabsorption In the Isobar Regionmentioning

confidence: 94%

Covariant propagator of the Rarita-Schwinger field in the nuclear medium

Korpa

Dieperink

2004

Phys. Rev. C

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A formalism for representing the fully relativistic propagator of the Rarita-Schwinger field in the nuclear medium is developed. Using a convenient basis for expanding the propagator it is shown that it can be represented by 40 energy and momentum dependent quantities which can be decomposed into an 2×2 and an 6×6 matrix. In this way calculations reduce to matrix multiplication. Using the presented formalism the full relativistically covariant contribution of the pion-nucleon loop to the isobar self energy and propagator in isospin-symmetric spin-saturated nuclear medium is computed. Utilizing this propagator the photoabsorption cross-section on in-medium nucleons in the isobar region is calculated and the result compared with experimental data.

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“…For all complex nuclei A > 6 a resonance-like cross section has been observed. The surprising result, however, is the scaling of the cross section with the atomic number A; the quantity (or-r, T / A) being described by a "Universal Curve" (equal shapes, mean energies and magnitude) [6,7,12]. The observed widths are larger than in the case of the proton as expected due to the Fermi motion and AN ~ NN coupling.…”

Section: Introductionmentioning

confidence: 61%

“…can be investigated by measuring fission fragment mass distributions, since the fragment mass split (symmetric versus asymmetric fission) is highly sensitive to the excitation energy of the residual fissioning system. quanta, tagged photons) [10,11,12]. For all complex nuclei A > 6 a resonance-like cross section has been observed.…”

Section: Introductionmentioning

confidence: 89%

Photofission of235U and238U at intermediate energies: absolute cross sections and fragment mass distributions

Frommhold

Steiper

Henkel

et al. 1994

Z. Physik A - Hadrons and Nuclei

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Abstract. The total photofission cross section c%,F for Z35U and 238U has been measured in the energy range 50< E.y < 800 MeV at the 855 MeV Mainz Microtron MAMI using energy and time tagged photons (Glasgow Tagger) and a 47r arrangement of position sensitive fragment detectors. Besides the absolute photofission cross section c%,F, which almost completely exhausts the total photon absorption cross section for these nuclei, fragment mass distributions in this energy domain were determined via time of flight techniques (TOF). The results for the total photofission cross sections c%,F normalized to the atomic number A for both isotopes coincide, and agree in the A-resonance region, within the systematic errors, with the socalled "Universal Curve" C%,T/A of the total photon absorption cross section crT,T. At higher energies the cross sections exhibit a smooth behaviour. In particular, it is shown for the first time that there is n__0o resonancelike shape near the D13 resonance (at ~ 710 MeV) as observed for the free proton. This complete suppression of the DI3 resonance in complex nuclei is not yet understood on a microscopic level. The fragment mass distributions show a predominantly mass symmetric fission. However, contributions from mass asymmetric fission at some photon energies may give a hint of an increased mass asymmetric fission after the onset of the pion and two pion channels.

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Measurement of the total cross section for 235U and 238U photofission in the δ-resonance region

Cited by 63 publications

References 14 publications

Analysis of209Bi and238U photofission cross section in the quasi-deuteron region of photonuclear absorption

Analysis of209Bi and238U photofission cross section in the quasi-deuteron region of photonuclear absorption

Covariant propagator of the Rarita-Schwinger field in the nuclear medium

Photofission of235U and238U at intermediate energies: absolute cross sections and fragment mass distributions

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