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IAEA1332 SPEC.

SPEC, Neutron and Charged-Particle Reactions by Optical Model, Evaporation Model

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1. NAME OR DESIGNATION OF PROGRAM:  SPEC.
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2. COMPUTERS
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Program name Package id Status Status date
SPEC IAEA1332/01 Arrived 08-MAR-2001

Machines used:

Package ID Orig. computer Test computer
IAEA1332/01 Many Computers
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3. DESCRIPTION OF PROGRAM OR FUNCTION

SPEC is a program for calculating the neutron or charged particles (p, d, t, He3, alpha) induced reactions of medium-heavy nuclei in the incident energy range up to 60 MeV including 6 emission processes. For those reaction channels contributed only by 1-5 emission processes the incident energy can go up to 100 MeV. SPEC is constructed within the framework of optical model, master equation of the exciton model, and the evaporation model. In the first and second particle emission processes, we consider preequilibrium emission and evaporation; in 3-6 particle emission processes, we only consider evaporation. The preequilibrium and direct reaction mechanisms of gamma emission are also included in this program. The  effect of recoil nucleus is considered for calculating spectra. Program SPEC includes the first to the sixth particle emission processes.



a+A -> b+B*, a=n, p, alpha, d, t, He3, b=n, p, alpha, d, t, He3,gam   B* -> c+C*,   c=n, p, alpha, d, t, He3, gamma

C* -> d+D*,   d=n, p, alpha, d, t, He3, gamma

D* -> e+E*,   e=n, p, alpha, d, gamma

E* -> f+F*,   f=n, p, gamma

F* -> g+G*,   g=n, p, gamma



When a particle is emitted, the residual nucleus may emit another particle or gamma ray continuously if the excited energy is large enough to overcome the binding energy. Generally speaking, the gamma emission cross section is much less than neutron emission cross section when neutron emission channel is open, we assume that  after gamma ray is emitted the residual nucleus do not emit any particle except after the first gamma ray emission process the particle or gamma are allowed to be emitted. Thus, 7 channels can be opened for the first emission process, 49 channels for the second emission process, 252 channels for third emission process, 1080 channels for forth emission process, 2592 channels for fifth emission process, and 5184 channels for sixth emission process.

The Gilbert-Cameron level density formula was applied in program SPEC. The inverse cross sections of the emitted particles used in statistical theory are calculated from the optical model. The partial widths for gamma-ray emission are calculated based on the giant dipole resonance model with two resonance peaks in both the evaporation model and exciton model.

In the optical model calculation, we usually adopt the Becchetti and Greenlees's phenomenological optical potential, which parameters are usually given by a program for automatically searching the optimum optical model parameters. We use Neumanove methods to solve  the radial equation in optical model. Coulomb wave functions used in optical model are calculated by the continued fraction method.

SPEC does not calculate the direct inelastic scattering and compound nucleus elastic scattering cross sections, but the calculated direct inelastic scattering cross sections by the collective excitation distorted-wave Born approximation and compound nucleus elastic scattering results by Hauser-Feshbach model can be added by the input data of the program SPEC.

The following nuclear data can be calculated with the program SPEC: total emission cross sections and spectra of all emitted particles; for first to sixth particle emission processes and different pick-up configurations (l,m); the various yield cross sections; total and elastic scattering cross sections (only for neutron as projectile); total reaction cross section; nonelastic scattering cross sections; radiative capture cross section; (x,np),  (x,n alpha), (x,2n), (x,3n), (x,4n), (x,5n), (x,6n) cross sections and so on.
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4. METHOD OF SOLUTION

The radial wave function in optical model is solved by the Neumanove method and the double precision arithmetic is used. The step length is 0.1 fm and the step number is 150 in solving radial equation. The Gaussian ten point numerical integration method is used.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

1) The calculations are restricted to the medium-heavy nuclei,
   for which the fission reactions are absent.
2) The incident particle is restricted to n(neutron), p(proton),
   d(deuteron), alpha(helium-4), t(triton), and He3(helium-3).
   The outgoing particles only include n(neutron) and the above 5
   charged particles as well as gamma photon.
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6. TYPICAL RUNNING TIME

The running time depends on the values of the incident energies and the kind of the target for calculation of various cross sections and energy spectra. For example, calculation  of all reaction cross sections at incident energy 50 MeV for target  nucleus Fe56 with neutron as incoming particle takes 48 minutes CPU  time in microscopic computer 486 and 4.7 minutes CPU time in SUN work station.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:  CMUP2 and UNF.
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9. STATUS
Package ID Status date Status
IAEA1332/01 08-MAR-2001 Masterfiled Arrived
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10. REFERENCES

- M. Blann, Ann. Rev. Nucl. Sci., 25, 123(1975).
- J. M. Akkermans and H. Gruppelaar, Phys. Let., 157B, 95(1985).
- A. Iwamoto and K. Harada, Phys. Rev., C26, 1821(1982).
- K. Sato, A. Iwamoto, and K. Harada, Phys. Rev. C28, 1527(1983).
- Zhang Jing-shang, Wen Yuan-qi, Wang Shu-nuan, Shi Xiang-jun,
  Commun. in Theor. Phys., ( Beijing, China ), 10, 33(1988).
- Zhang Jing-shang, Yan Shi-wei, Wang Cui-lan, Z. Phys., A344,
  251(1992).
- Zhang Jing-shang and Shi Xiang-jun, INDC(CRP)-014/L.$
- A. Gilbert, C. G. W. Cameron, Can. J. Phys., 43, 1446(1965).
- F. D. Becchetti and G. W. Greenlees, #FK Phys. Rev., 182,
  1190(1969).
  C. M. Perey et al., Atomic Data and Nuclear Data Tables, 17,
  3(1976).
- A. R. Barnett et al., Computer Phys. Commun., 8, 377(1974).
- P. D. Kunz, 'Distorted Wave Code DWUCK4", University of Colorado,
  USA.
IAEA1332/01, included references:
- Shen Qingbiao and Zhang Jingshang:
  The User's Manual for Program SPEC
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11. MACHINE REQUIREMENTS:
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
IAEA1332/01 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

NDP system in microscopic computer 486. OS system in SUN work station.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

1) The double precision arithmetic is necessary.
2) The unit number is 4 for input and 7 for output.
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15. NAME AND ESTABLISHMENT OF AUTHORS

    Shen Qing-biao and Zhang Jing-shang
    China Institute of Atomic Energy, Beijing, P. R. China
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16. MATERIAL AVAILABLE
IAEA1332/01
test-case data   mag tapeSPECI.DAT Input data set of the example    DATTP
test-case output mag tapeSPECO.DAT Output data set of the example   OUTTP
source program   mag tapeSPEC.FOR Source code                       SRCTP
miscellaneous    mag tapeSPEC.ABS SPEC abstract                     MISTP
report                   User's manual for program SPEC             REPPT
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17. CATEGORIES
  • A. Cross Section and Resonance Integral Calculations

Keywords: alpha particles, charged particles, deuterons, direct interactions, evaporation model, gamma radiation, helium-3, neutron reactions, neutron recoil, optical models, precompound-nucleus emission, protons, tritons.