Fission of Al, Ti, Co, Zr, Nb, Ag, In, Nd, Sm and Ta nuclei induced by (0.8÷1.8) GeV photons

Lima, D. A. De; Martins, J. B.; Tavares, O. A. P.

doi:10.1007/bf02789022

Cited by 11 publications

(13 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both pion signs are used for this study, which thus allows an examination of the roles of charge, excitation energy, and fission barriers across the local area where shell-dependent effects might be strong. Similar studies of photofission at intermediate energies in this mass region provide a complementary study of these fission barriers [2]. Fission barriers computed for low nuclear excitation energy show a local increase of 10 MeV (or 40%) with a full width in A of about 20 units, centered at 208 Pb [3].…”

Section: Introductionmentioning

confidence: 96%

Barriers for pion-induced fission near A = 208

Barros¹,

Silva

Suita

et al. 1997

Z Phys A - Particles and Fields

View full text Add to dashboard Cite

Measured fission cross sections for π + and π − beams of 150 MeV on isotopically separated targets near A=208 show a smooth dependence of the fission probability on the target mass, without any indication of the increased fission barriers expected for fission at low excitation near doubly magic 208 Pb. Extraction of fission barriers from these data is attempted for a range of possible excitation energies, finding that these barriers are near 8 MeV near A=208, without much sensitivity to the assumed excitation energy.

show abstract

Section: Introductionmentioning

confidence: 96%

Barriers for pion-induced fission near A = 208

Barros¹,

Silva

Suita

et al. 1997

Z Phys A - Particles and Fields

View full text Add to dashboard Cite

show abstract

“…The final values of s are then obtained from a smooth trend of s versus Z 2 /A. We have applied the present, phenomenological, semiempirical photofission approach to analyse the photofissility data obtained at 1 GeV for a number of pre-actinide, intermediate-mass, and less massive nuclei [3,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Some data for actinide targets [3,11,14,[25][26][27][28] are also presented.…”

Section: The Very Interesting Results Reported Above Suggest Parametrmentioning

confidence: 99%

“…Some data for actinide targets [3,11,14,[25][26][27][28] are also presented. Photofissility is defined as the ratio of the photofission cross section, σ f , to the total nuclear photoabsorption cross section, from data reported in [3,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. The calculated trend from the present model (f c ) is shown by the full line.…”

Section: The Very Interesting Results Reported Above Suggest Parametrmentioning

confidence: 99%

Photofissility at 1 GeV for nuclei throughout the periodic table

Tavares¹,

Duarte²,

Morcelle³

et al. 2005

Braz. J. Phys.

Self Cite

View full text Add to dashboard Cite

A new approach to evaluate nuclear photofissilities at incident photon energies above the pion photoproduction threshold has been recently developed and proved to describe successfully the fissilities of nat Pb and 232 Th target nuclei at energies ∼ 0.2 − 4.0 GeV. The method is merely a simple, semiempirical description of the photofission reactions in which fissility, f , is governed by two basic quantities, namely, i) the first-chance fission probability,f 1 , for the average cascade residual, and ii) the slope,s, of the chance-fission probability associated with the average evaporative sequence of fissionable residuals. In the present work we have extended this approach to analyse photofissity data that have been accumulated over the past fourty years or so, measured at 1 GeV, for nearly fourty target nuclei extending from Ti up to Np. Results have shown that the variation of fissility with Z 2 /A could be described quite satisfactorily by the proposed model.Recently, a new approach to evaluate nuclear photofissilities at incident photon energies E γ 200 MeV has been developed to overcome the calculational difficulties imposed by the available Monte Carlo codes when the target nuclei are expected to exhibit low, or very low, fissility-values ( 1%), as is the case for pre-actinide, intermediate-mass, and less massive nuclei [1]. The method is a simple, semiempirical approach that has proved to work quite well in describing the fissilities of nat Pb and 232 Th target nuclei induced by ∼ 0.2 − 4.0 GeV photons, which have been measured at the Thomas Jefferson Laboratory by Cetina et al [2,3].Since photofissility values for actinide targets have been already analysed to some detail in the framework of Monte Carlo calculations [3,4] we decided, in the present work, to extend this approach [1] to analyze photofissility data that have been accumulated over the past fourty years or so, measured at 1 GeV, for nearly fourty target nuclei extending from Ti up to Np. Results have shown that the variation of fissility with Z 2 /A can be described quite satisfactorily by the proposed model. We remark that the trend of fissility is seen as an inverse reflection of the behaviour of the height of the fission barrier with Z 2 /A [5,6].Monte Carlo calculations are, at present, the main tool to describe quantitatively both the cascade and fissionevaporation competition processes, as well as to obtain the total fission probabilities (photofissility values) for a number of photofission reaction cases. However, for cases where the target nucleus is expected to have low fissility-values (pre-actinide, intermediate-mass, and less massive nuclei), the available codes may reveal themselves very time-consuming in obtaining a calculated fissility-curve of acceptable uncertainty over a large energy-interval such as ∼ 0.2 − 4.0 GeV. This fact led us to develop an alternative method to calculate nuclear photofissility-values semiempirically. This approach is based on the current, two-step model for intermediateenergy photonuclear reactions...

show abstract

“…4 for the fission probabilities of bismuth. [36,37], and for fission induced by 0.8 to 1.8 GeV photons by circles [35]. The curve is the fit to the = data in Fig.…”

Section: Comparisons and Discussionmentioning

confidence: 98%

Mass and energy dependence of pion-induced fission

Peterson

deBarros

deSouza

et al. 1995

Z. Physik A - Hadrons and Nuclei

View full text Add to dashboard Cite

Abstract. Data for fission induced by pi meson beams from 80 to 500 MeV are presented for nuclei from Fe through Pu as measured by solid state track detectors. The general trends for binary fission with ~+ are reproduced fairly well by a calculation in the 'high excitation' limit with standard level density and fission barrier parameters, but 7c-data are underpredicted. A universal dependence of the binary fission probabilities with the fissility (Z + 1)2/A is found to be valid for both pion beam charges for all beam energies below the delta resonance. Probabilities for observing three fragments with ~+ are not reproduced by a ternary fission application of the model found to work for binary fission.

show abstract

Fission of Al, Ti, Co, Zr, Nb, Ag, In, Nd, Sm and Ta nuclei induced by (0.8÷1.8) GeV photons

Cited by 11 publications

References 13 publications

Barriers for pion-induced fission near A = 208

Barriers for pion-induced fission near A = 208

Photofissility at 1 GeV for nuclei throughout the periodic table

Mass and energy dependence of pion-induced fission

Contact Info

Product

Resources

About