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New CHIPS elastic cross-sections

Mikhail Kosov , Hadronic meeting,26/02/10. New CHIPS elastic cross-sections. Introduction. Inelastic pA cross-sections have been tuned by s in (“ex”)= s tot (ex)- s el (CHIPS).

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New CHIPS elastic cross-sections

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  1. Mikhail Kosov, Hadronic meeting,26/02/10 New CHIPS elastic cross-sections

  2. Introduction Inelastic pA cross-sections have been tuned by sin(“ex”)=stot(ex)-sel(CHIPS). At some energies sin(“ex”) differs from direct sin(ex). The CHIPS sel(NA) approximation must be improved there. The next step is to improve the CHIPS sel(hA) CHIPS approximation, using sel(“ex”)=stot(ex)-sin(CHIPS) “data” Use CHIPS Glauber calculations of sel

  3. n n n It means that the elastic nPb CHIPS cross-sections must be improved

  4. How to use the stot=sin+sel CHIPS test tool • Ideally sin(CHIPS) must coincide with stot-sel(CHIPS), as this is shown for the neutron-aluminium interactions. • This is not true for neutron-lead interactions for p<0.3. • In this presentation cleaning up of sel of pA interaction is presented: a new analytics 2D-functionsel(p,A) for pA. • As a next step, CHIPS 2D-functions sel(p,A) for hA are implemented in Geant4 and compared with other G4 sel. • An upgrade for neutron-nuclear elastic is started. At low energies it demands individual fit for 388 target-isotope. • New CHIPS sel(nA) improves both HP & LHEP (2 in 1). • A G4Had wrapper for the CHIPS elastic cross-sections is implemented to be used by other G4 hadronic processes.

  5. A bug?

  6. CHIPS parameterization of sel for hA • CHIPS calculation: sel=∫(1-e-sT(b)/2)2d2b (---------) • Fortunately, at low energies there are pA data. • The CHIPS sel(pA) function is good in D-region • The Barashenkov’s sel(pA) fit does not look much better than the LHEP (GEISHA) fit (all energies) • The threshold of the Glauber-Gribov and LHEP fits is too low and BGG has too high thresholds • In the GeV region all G4 fits (other than CHIPS) have strange position of the cross-section maxima • The CHIPS pA fit is significantly below other G4 fits, what can a bit accelerate CHIPS calculations

  7. New CHIPS nA elastic for light nuclei • New CHIPS nA Elastic is based on • Interaction length fit (1/v part) • Interaction radius fit (constant part) • Absorptive band (below 20 MeV=200 MeV/c) • Coincidence with new high enrgy pA CHIPS elastic • It is not that detailed as the tabulated HP fit, but it covers more isotopes and fits updated ENDF • Big discrepancy with LHEP at high energies • New CHIPS nA elastic cross-sections are covering both low and high energies, do not have any tables and works faster than the HP+LHEP

  8. 53 days

  9. Conclusion • New CHIPS elastic pA fit is better than old one • At low energies there are big uncertainties in sel • The best existing (not CHIPS) approximation is the Barashenkov fit (only pA & pA) • The Glauber-Gribov fit is not reliable at low E • BGG has too high threshold and, probably, bugs. • The pA ENDF/B VII is too low, but the maxima positions coincide with the integrated CHIPS fit • CHIPS hA fit is usually below other G4 fits, but at low E CHIPS electromagnetic must be added • New low energy nA is competitive with HP and more detailed, and at high E is better than LHEP

  10. Thank you Backup slides following

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