CHIPS_HP physics list

1. CHIPS_HP physics list M. Kosov (ITEP/VNIIA)

2. Intro: Recent bug fixes in CHIPS • Reproducibility bug fix (QuasiElastic, Alberto, Witold) • Bug fixes in anti-proton capture (GrLn=GreenLine, Head) • Bug fix in interface to CHIPS XS for G4XSDataTables • An extensive weekend test results: • Check for DE2+Dpx2+Dpy2+Dpz2 > 0.5 MeV2 events • Not found for anti-proton captures on: • Carbon 15 500 000 events • Nitrohen 16 500 000 events • Oxigen 17 500 000 events • The heavier nuclei the faster calculations (for multi-quasmons) • The bug fixes are committed together with the new G4QNGamma process split out of G4QInelastic (GrLn) M.Kosov, CHIPS_HP Phys List

3. Main reasons for the CHIPS_HP • The (n,g) and inelastic G4 CHIPS processes were joined together in one Element-wise “inelastic” process, whilst such a joined process is known as non-elastic. To be consistent at low energies the processes are split in two. • The processes are Element-wise, whilst at low energies they must be Isotope-wise as in HP or in TPT processes. • To combine CHIPS with HP one more process is needed: a fission process, the old version of which is planned to be implemented in G4 CHIPS from TPT. • TPT (Toolkit for Particle Transport, VNIIA) is not an open code project above Geant4, where the algorithms and data bases with nonproliferation restrictions are used. M.Kosov, CHIPS_HP Phys List

4. 20 MeV 20 MeV M.Kosov, CHIPS_HP Phys List

5. M.Kosov, CHIPS_HP Phys List

6. Fission! M.Kosov, CHIPS_HP Phys List

7. Lessons from the pictures • For heavy nuclei the Fission process should be split out of the Inelastic process. • The Isotope-wise cross-sections for the same Element can be very different • It is worth to fit Tot-El-NGamma-Fission, NGamma & Fission separately • In TPT there is additional (n,n/g) process M.Kosov, CHIPS_HP Phys List

8. Mixing of CHIPS & HP processes • In the CHIPS physics lists it is possible to combine processes by the G4QDiscreteProcessMixer class. • In CHIPS there is no transition regions – only energy boundaries (in decreasing order). • In the new CHIPS_HP physics list for neutrons: • G4QInelastic is mixed with HPInelastic (E<19.9 MeV) • G4QNGamma is mixed with HPCapture (E<19.9 MeV) • HPFission is used so far without CHIPS (no E>20 MeV) • G4QElastic process is used without HPElastic M.Kosov, CHIPS_HP Phys List

9. Comparison of CHIPS_HP with other PL’s A bug was found in the HP_Elastic: the time was not continued for the recoil nuclei, so an “early signals” were found in the low energy neutron simulation (Ilya Kudinov). The HP_Elastic was substituted by the CHIPS Elastic. It accelerated the LE neutron simulation (see the table) with a factor of two and no “time bugs” were found. The Response & Resolution differences should be compared with measurements. In future the TPT_CHIPS or improved Geant4 CHIPS physics lists can be compared with the Geant4 CHIPS_HP physics list (& other _HP). M.Kosov, CHIPS_HP Phys List

10. Conclusion • At low energies the new CHIPS_HP physics list is faster than other Geant4 _HP physics lists, because it uses a fast CHIPS Elastic process, but the QElastic can be too big at low energies. • A bug in HPElastic (zero start time for recoilnuclei, found by Ilya Kudinov) should be fixed. • A new CHIPS Fission Isotope-wise process should be created (valid above 20 MeV). • The CHIPS (n,g) & Inelastic processes should be upgraded to the Isotope-wise level. M.Kosov, CHIPS_HP Phys List