Prepared By: A.K.M. Moinul Haque Meaze * Center for High Energy Physics, Kyungpook National University Daegu , Korea Course Title : Phenomenology Honorable Professor Kihyeon Cho Practice before KPS Autumn Meeting The 14 th October

 D. Son  G.N. Kim  A.K.M. M. H. Meaze  H. Ahmed Center for High Energy Physics Kyungpook National University Daegu , Korea  W. Namkung  V. Skoy  Y.S. Lee  H.S. Kang  M.H. Cho  I.S. Ko Pohang Accelerator Laboratory Pohang University of Science and Technology Pohang ,Korea The People Involved Practice before KPS Autumn Meeting The 14 th October

6 In order to obtain neutron total cross section, a transmission experiment was carried out on the sample of Hafnium (Hf) at the Pohang Neutron Facility. A 6 Li- ZnS(Ag) scintillator detector and time of flight technique were used to measure the transmission. The PNF consists of 100 MeV electron linac, a water cooled Tantalum (Ta) target and four position automatic sample changer controlled remotely by CAMAC data acquisition system. The distances from the water cooled Ta target to the sample changer and to the scintillator are 5.4m and 10.8m respectively. Notch filter consists of Cobalt (Co) Indium (In) and Cadmium (Cd) which has a large resonance peaks in the spectrum to determine the background levels. To reduce gamma flash originated from the neutron target we have employed a neutron–gamma separation system based on their different pulse shape. For this measurement the total energy range was covered from 0.1eV to 100eV. The present result was compared with ENDF/VI. Practice before KPS Autumn Meeting The 14 th October

Cross Section Neutron Cross Section Macroscopic Cross Section Microscopic Cross Section Absorption cross sectionScattering Cross Section Capture Cross Section Fission Cross Section Elastic Scattering Cross Section Inelastic Scattering Cross Section Practice before KPS Autumn Meeting The 14 th October

Information about the relative probabilities of different reactions provides clues to the problem of nuclear structure and offers a testing ground for ideas about nuclear forces. So cross section is used to obtain information about the internal structure of atomic nuclei and their constituents. The possibility of achieving a chain reaction and to design and development of a nuclear reactor depend strongly on the values of neutron cross section Hafnium is one of the rare earth isotopes has a relatively large total cross section in the thermal energy region which is a useful absorbing material for control rods of the thermal reactor. Flight path Source Sample Detector Incident fluxTransmitted flux Fig.: Geometrical arrangement of measurement of total cross section Practice before KPS Autumn Meeting The 14 th October

Figures (Clockwise): PNF Linac, Target, Moderator and Sizes of target plates 10 Ta Plates - 3 (40 mm  x 2mm t) - 2 (40 mm  x 3mm t) - 1 (40 mm  x 4mm t) - 4 (40 mm  x 6mm t) with 2 mm t Ti cover Ta 161 ( ,n)Ta 160 Practice before KPS Autumn Meeting The 14 th October

Figures (Clockwise): Outside of TOF area, Data acquitting system and sample changer Practice before KPS Autumn Meeting The 14 th October

Name & Properties of Sample We have used following equations Name of the Sample SymbolArea (cm 2 ) Thickness (mm) Atomic weight (amu) Density (g-cm -3 ) Atomic density (cm -2 ) HafniumHf5x x10 21 Beam Condition Energy:65MeV Repetition rate:10Hz Pulse width:1microS Practice before KPS Autumn Meeting The 14 th October

Fig.1:Channel Vs Counts Fig.2:Background Fitting Practice before KPS Autumn Meeting The 14 th October

Fig.3: TOF with background level Fig.4: Resonance fitting 1 Practice before KPS Autumn Meeting The 14 th October

Fig.5: Resonance fitting 2 Fig.6: Resonance fitting 3 Practice before KPS Autumn Meeting The 14 th October

Fig.7: Resonance fitting 4 Fig.8: Fit of TOF path to resonances τ=(0.299±0.001)µS L=(10.800±0.020)m Practice before KPS Autumn Meeting The 14 th October

Fig.7: Energy Vs Cross Section *The preliminary results of the transmission analysis are fair with ENDF except resonances area *The analysis is still going on and we expect to show final results in near future Practice before KPS Autumn Meeting The 14 th October