https://repository.auw.edu.bd/handle/123456789/734 Wed, 10 Jun 2026 02:19:23 GMT 2026-06-10T02:19:23Z https://repository.auw.edu.bd/handle/123456789/938 Neutron induced reactions for the s process, and the case of Fe and Ni isotopes Meaze, AKM Moinul Haque Neutron capture cross sections are the key nuclear physics input to understand nucleosynthesis of the slow neutron capture process (s process). At the neutron time of flight facility n_TOF at CERN neutron capture cross sections of astrophysical interest are measured over a wide energy range. A measurement campaign to determine the stellar (n, γ) cross sections of Fe and Ni isotopes is currently being pursued. First results on the stellar cross section of 62Ni(n, γ) confirm previous experimental results. The cross section of the radioactive s-process branching 63Ni was measured for the first time at stellar energies and is about a factor of 2 higher than theoretical predictions. Future facilities and upgrades will allow to access a number of other radioactive nuclides which are crucial for understanding physical conditions of s-process environments. Sun, 01 Jan 2012 00:00:00 GMT https://repository.auw.edu.bd/handle/123456789/938 2012-01-01T00:00:00Z https://repository.auw.edu.bd/handle/123456789/937 PRESENT STATUS AND FUTURE PROGRAMS OF THE n_TOF EXPERIMENT Meaze, AKM Moinul Haque The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology. The most relevant measurements performed up to now and foreseen for the future will be presented in this contribution. The overall efficiency of the experimental program and the range of possible measurements achievable with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the n_TOF spallation target, might offer a substantial improvement in measurement sensitivities. A feasibility study of the possible realisation of the installation extension will be also presented. Sun, 01 Jan 2012 00:00:00 GMT https://repository.auw.edu.bd/handle/123456789/937 2012-01-01T00:00:00Z https://repository.auw.edu.bd/handle/123456789/936 Simultaneous measurement of neutron-induced capture and fission reactions at CERN Meaze, AKM Moinul Haque The measurement of the capture cross-section of fissile elements, of utmost importance for the design of innovative nuclear reactors and the management of nuclear waste, faces particular difficulties related to the γ-ray background generated in the competing fission reactions. At the CERN neutron time-of-flight facility n TOF we have combined the Total Absorption Calorimeter (TAC) capture detector with a set of three 235U loaded MicroMegas (MGAS) fission detectors for measuring simultaneously two reactions: capture and fission. The results presented here include the determination of the three detection efficiencies involved in the process: εTAC (n, f), εTAC (n, γ) and εMGAS(n, f). In the test measurement we have succeeded in measuring simultaneously with a high total efficiency the 235U capture and fission cross-sections, disentangling accurately the two types of reactions. The work presented here proves that accurate capture cross-section measurements of fissile isotopes are feasible at n TOF. Sun, 01 Jan 2012 00:00:00 GMT https://repository.auw.edu.bd/handle/123456789/936 2012-01-01T00:00:00Z