Nucleon, Two-Nucleon Reactions Above 100 MEV

Grover, J. R.; Caretto, A.A.

doi:10.1146/annurev.ns.14.120164.000411

Cited by 69 publications

(3 citation statements)

References 97 publications

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“…Also, we have performed the calculations for the (p,pn) reactions based on the mechanism of inelastic scattering of one nucleon in the diffuse surface of the nucleus followed by the evaporation of another particle from the excited residual nucleus (3)(4)(5).…”

Section: Introductionmentioning

confidence: 99%

Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au

Dewanjee¹,

Saha²,

Yaffe³

1968

Can. J. Chem.

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Thick-target recoil experiments were performed to study (p,pn) reactions induced in 6 5 C~ and 9 7 A~ in the energy range of 2&85 MeV and the average ranges projected in the forward, backward, a n d perpendicular directions were determined. Recoil parameters have been calculated t o show approximately the amount of energy transfer and their energy dependence. The average range results have been compared with statistical theory, cascade-evaporation (85 MeV only), and inelastic scattering model calculations. The statistical calculations show reasonable agreement up to 3 0 4 0 MeV. However, the calculated projected range values, based o n the cascade-evaporation and the inelastic scattering models, are consistently lower than the measured values. The analyses of the projected range values support the prevalent view that at low energies (-3&35 MeV), the compound nucleus mechanism is predominant and at higher energies, the direct interaction mechanism makes a major contribution.Canadian Journal of Chemistry, 46, 3157 (1968) IntroductionThe study of simple nuclear reactions in the energy range of approximately 20-100 MeV is interesting because of the gradual transition in the reaction mechanism that occurs in this energy region. From the threshold to some intermediate energy range (30-40 MeV) the reactions seem to be governed by the formation and subsequent decay of a compound nucleus. At higher energies the available data are at present best explained by a direct interaction mechanism in which the reactions take place in a two-step cascade-evaporation process or in a one-step knock-out phase.Recoil measurements provide a useful tool for the determination of momentum transfer and thus yield valuable information about the reaction mechanism. When a compound ilucleus is formed, full transfer of incident momentum from the projectile to the struck nucleus occurs. With the direct interaction mechanism only partial momentum transfer takes place.In the present study, we have measured the average ranges of the products formed in the

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Section: Introductionmentioning

confidence: 99%

Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au

Dewanjee¹,

Saha²,

Yaffe³

1968

Can. J. Chem.

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“…Simple nuclear reactions of the form (a,aN), where a is the incident projectile and N is the nucleon removed from the nucleus, have been a field of extensive investigation over the years (2), mainly because this class of reactions represents the simplest form of the cascade-evaporation model and impulse approximation outlined in the previous section. In addi tion, such reactions are thought to occur mainly on the nuclear surface, damage the nucleus only slightly, and are therefore, of value in probing certain aspects of nuclear structure.…”

Section: Simple Nuclear Reactionsmentioning

confidence: 99%

Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

Jacob

1975

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The effect of free-particle collisions in simple "knockout" reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated in a two part study by using protons and pions as the In the second part of this thesis, cross section measurements for (iT.rcN) and other more complex pion-induced spallation reactions were -ixmeasured for the light target nuclei N, 0, and F from 45 to 550 incident pion energy. These measurements indicate rlearly a broad peak in the excitation functions for both (TT.TTN) and fn.X) reactions near 180MeV incident pion energy. This corresponds to the large resonances ob served in the free-particle IT p and ir~p cross sections at the same en ergy. Striking differences in (n,nN) cross section magnitudes are observed among the light nuclei targets. The experimental cross section ratio R _/ + = a(Tr",Tf"n)/a(T7*,TiN) at 180 MeV is 1.7 ± 0.2 for all three targets.The experimental results are compared to previous pion and analogous pro The second stage of this process is the subsequent de-excitation of the excited residual cascade nucleus in a manner similar to that for lew energy nuclear reactions i.e., by emission of nucleons, alpha particles, photons, or even fission fragments. This is termed the "evaporation"stage and has a time scale that is on the order of 10 to 1000 times as long as the cascade stage. Thus, the average de-excitation time for an -20 -18 excited nucleus wouli last about 10 -10 seconds.In light of this mechanism, the wide distribution of product, nu clides formed in a high energy nuclear reaction can be logically explained.Depending upon the complexity of the nucleonic cascade, high as well as low energy deposition events will occur,which in turn, create a wide range of final nuclides after completion of the second or "evaporation" stage of the reaction.-3-This model was further developed by Chew and co-workers (6 Z'j, who proposed the "impulse approximation". This particular approach postulated that the target nucleus would appear to a high energy projectile as a collection of "free" nucleons, rather than an integral cluster, and that the following assumptions should hold (1) The incident particle never in teracts with more than one nucleon at any one time.[2) The amplitude of each incident wave falling on each nucleon is the sane as if the nucleon were a free particle. (3) The binding forces between constituent nucleons in the nucleus are negligible during the strong interaction of the in cident particle with the system.Assumptions (1) and (2) are somewhat oversimplified for systems heavier than the alpha particle. The seemingly paradoxical "impulse"assumption (3) is reconciled by the fact that for very short collision times x, the energy E of the system cannot be determined to better than AE~h/x , a simple application of the uncertainty principle. In spite of these apparent shortcomings, the impulse approximation has been success fully used to correlate a broad spectrum of empirical data and still re mains the basic assumption i...

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“…Following a cascade, the nucleus is left with some residual excitation energy, which is used cARETTO (23) and by WATTENBERG. (2P) An i n the evaporation of nucleons and other particles of small mass number.…”

Section: K -+ P -+ F I -mentioning

confidence: 99%

A Study of Elementary Particle Interactions for High-energy Dosimetry

Katoh¹,

Turner²

1967

Health Physics

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Types of interactions are classified and discussed from the standpoint of their relative importance in the dosimetry of particles with energies up to several tens of GeV. The known elementary particles are treated individually; threshold energies, cross sections, and important reactions leading to their production and absorption are given. The principal reactions by means of which these particles can contribute to dose and dose equivalent are described. The data reviewed and summarized here are intended to provide a starting point for detailed calculations or analyses of dose from high-energy particles.

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Nucleon, Two-Nucleon Reactions Above 100 MEV

Cited by 69 publications

References 97 publications

Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au

Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au

Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

A Study of Elementary Particle Interactions for High-energy Dosimetry

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Nucleon, Two-Nucleon Reactions Above 100 MEV

Cited by 69 publications

References 97 publications

Average recoil ranges of 64Cu and 196Au produced by protons of 20–85 MeV energy in 65Cu and 197Au

Average recoil ranges of 64Cu and 196Au produced by protons of 20–85 MeV energy in 65Cu and 197Au

Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

A Study of Elementary Particle Interactions for High-energy Dosimetry

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Product

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Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au

Average recoil ranges of ⁶⁴Cu and ¹⁹⁶Au produced by protons of 20–85 MeV energy in ⁶⁵Cu and ¹⁹⁷Au