Bulletin of the American Physical Society
3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009; Waikoloa, Hawaii
Session LC: Applications of Nuclear Physics II |
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Chair: Anna Hayes, Los Alamos National Laboratory Room: Kohala 1 |
Saturday, October 17, 2009 2:00PM - 2:15PM |
LC.00001: A New Method for Identifying Nuclear Isotopes Based Upon Polarized ($\gamma,n$) Asymmetries S. Stave, M.W. Ahmed, N. Brown, S.S. Henshaw, B.A. Perdue, P.-N. Seo, H.R. Weller, P.P. Martel, A. Teymurazyan, G. Warren Linearly polarized gamma rays between neutron threshold and 20 MeV can be a powerful tool for the interrogation of materials. In addition to their ability to penetrate shielding, they also induce the emission of several MeV neutrons. The ratio of neutron yields parallel and perpendicular to the plane of polarization as a function of outgoing neutron energy can provide a unique signature of isotopes. The photo-neutron yield asymmetries on $^{238}{\rm U}$ using linearly polarized photons have been measured at gamma-ray energies of 10 and 15 MeV using the High Intensity Gamma-ray Source (HI$\gamma$S). Additional targets included Pb, Bi and Fe. The results from these different targets will be compared to one another and to a calculated energy averaged result based upon previous unpolarized measurements and the assumption of pure E1 absorption. [Preview Abstract] |
Saturday, October 17, 2009 2:15PM - 2:30PM |
LC.00002: Experimental study of cross-sections for some medical radioisotopes production via proton induced nuclear reactions on natMo up to 40 MeV A.A. Alharbi, M. McCleskey, G. Tabacaru, B. Roeder, A. Banu, A. Spiridon, E. Simmons, L. Trache, R.E. Tribble, V. Goldberg The activation technique has been used to measure the excitation functions of the $^{nat}$Mo(p,xn), $^{nat}$Mo(p,pxn) and $^{nat}$Mo(p,$\alpha $xn) nuclear reactions up to 40 MeV using the proton beam from the K500 superconducting cyclotron of the Texas A{\&}M Cyclotron Institute. A stack was made from several groups of targets: $^{nat}$Mo,$^{nat}$Al and $^{nat}$Cu, with the Al and Cu as monitor foils to measure the excitation functions of the well known cross-sections monitor reactions $^{27}$Al(p,x)$^{24}$Na and $^{nat}$Cu(p,x)$^{62}$Zn simultaneously with the reactions induced on the targets. The determined excitation functions were compared with the available previous published research and with the ALICE-IPPE pre-compound hybrid model simulated calculations. The integral yield (MBq.$\mu $A$^{-1}$.h$^{-1})$ of the $^{nat}$Mo(p,X) nuclear reactions deduced using the excitation functions and the stopping power of $^{nat}$Mo. [Preview Abstract] |
Saturday, October 17, 2009 2:30PM - 2:45PM |
LC.00003: Precision photo-induced cross-section measurements using the monoenergetic and polarized photon beams at HI$\gamma$S A.P. Tonchev, C.R. Howell, E. Kwan, G. Rusev, W. Tornow, J.H. Kelley, C. Huibregtse, S.L. Hammond, D. Vieira, J.B. Wilhelmy A research program has been initiated at TUNL to perform precision ($\gamma$,$\gamma'$) and ($\gamma$,$xn$) cross-section measurements on actinide nuclei using the novel source of radiation at the High Intensity Gamma-ray Source (HI$\gamma$S) facility. This facility provides nearly mono-energetic ($\triangle$E/E $\pm$ 2\%) and intense (10$^8$ s$^{-1}$) photon beams after the recent upgrade. A precision knowledge of photoinduced processes is of practical importance for new reactor technologies, nuclear transmutation, and nuclear forensics. Our recent photodisintegration cross section measurements on radioactive $^{241}$Am targets in the energy range from 9 $<$ E$_\gamma$ $<$ 16 MeV will be presented. The experimental data for the $^{241}$Am($\gamma$,$n$) reaction in the giant dipole resonance energy region will be compared with statistical nuclear-model calculations. [Preview Abstract] |
Saturday, October 17, 2009 2:45PM - 3:00PM |
LC.00004: New measurements of (n,$\gamma$) and (n,fission) cross sections and capture-to-fission ratios for $^{233,235}$U and $^{239}$Pu using the DANCE $4\pi$ BaF$_2$ array T.A. Bredeweg, M. Jandel, M.M. Fowler, E.M. Bond, R.C. Haight, A.L. Keksis, J.M. O'Donnell, R. Reifarth, R.S. Rundberg, J.L. Ullmann, D.J. Vieira, J.B. Wilhelmy, J.M. Wouters, J.A. Becker, W.E. Parker, C.Y. Wu, J.D. Baker, C.A. McGrath Accurate neutron nuclear data are important to many issues in stockpile stewardship, nuclear reactor design and re-certification, nuclear non-proliferation and nuclear forensics. Of particular interest are the production and destruction reactions for all of the major and most of the minor actinides. The competition between capture and fission in many of the actinides presents both an obstacle and an opportunity for large $\gamma$ detector arrays such as DANCE. Additional instrumentation is required to deconvolve the two contributions to the total observed $\gamma$-ray spectrum. However, conducting a simultaneous measurement can simplify background treatment and other sources of systematic uncertainty. An outline of the current experimental program will be presented along with results from neutron capture measurements on $^{233,235}$U and $^{239}$Pu. [Preview Abstract] |
Saturday, October 17, 2009 3:00PM - 3:15PM |
LC.00005: Neutron capture cross section of $^{243}$Am M. Jandel The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for neutron capture cross section measurement on $^{243}$Am. The high granularity of DANCE (160 BaF$_{2}$ detectors in a 4$\pi $ geometry) enables the efficient detection of prompt gamma-rays following neutron capture. DANCE is located on the 20.26 m neutron flight path 14 (FP14) at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The methods and techniques established in [1] were used for the determination of the $^{243}$Am neutron capture cross section. The cross sections were obtained in the range of neutron energies from 0.02 eV to 400 keV. The resonance region was analyzed using SAMMY7 and resonance parameters were extracted. The results will be compared to existing evaluations and calculations. Work was performed under the auspices of the U.S. Department of Energy at Los Alamos National Laboratory by the Los Alamos National Security, LLC under Contract No. DE-AC52-06NA25396 and at Lawrence Livermore National Laboratory by the Lawrence Livermore National Security, LLC under Contract No. DE-AC52-07NA27344. \\[4pt] [1] M. Jandel et al., Phys. Rev. C\textbf{78}, 034609 (2008) [Preview Abstract] |
Saturday, October 17, 2009 3:15PM - 3:30PM |
LC.00006: Neutron beam provided by the neutron nucleus reaction instrument at the J-PARC MLF Koichi Kino, Michihiro Furusaka, Fujio Hiraga, Takashi Kamiyama, Yoshiaki Kiyanagi, Kazuyoshi Furutaka, Shinji Goko, Hideo Harada, Atsushi Kimura, Tadahiro Kin, Fumito Kitatani, Mitsuo Koizumi, Shoji Nakamura, Masayuki Ohta, Masumi Oshima, Yosuke Toh, Masayuki Igashira, Tatsuya Katabuchi, Motoharu Mizumoto We constructed a neutron beam line at the J-PARC materials and life science facility. This is called the neutron nucleus reaction instrument (NNRI) and measurements of the neutron capture cross sections for minor actinides and long-lived fission products have just begun. Prior to them we measured properties, which are spatial and energy distributions, and pulse shape, of the neutron beam provided by the NNRI. In this talk, we introduce the concept and structure of the NNRI at first. Then we report the properties of the neutron beam, which are experimentally obtained, and discuss their validity comparing to the prediction by simulation. [Preview Abstract] |
Saturday, October 17, 2009 3:30PM - 3:45PM |
LC.00007: Measurements of neutron capture cross sections using a 4$\pi $Ge spectrometer at the J-PARC/MLF/NNRI Hideo Harada, Kazuyoshi Furutaka, Shinji Goko, Atsushi Kimura, Tadahiro Kin, Fumito Kitatani, Mitsuo Koizumi, Shoji Nakamura, Masayuki Ohta, Masumi Oshima, Yosuke Toh, Masayuki Igashira, Tatsuya Katabuchi, Motoharu Mizumoto, Michihiro Furusaka, Fujio Hiraga, Takashi Kamiyama, Koichi Kino, Yoshiaki Kiyanagi, Toshiyuki Fujii, Junichi Hori, Koichi Takamiya The measurements of neutron capture cross sections have been started using a 4$\pi $Ge spectrometer at the neutron nucleus reaction instrument (NNRI) in the J-PARC/MLF. First test measurements using the spectrometer have been performed for radioactive samples such as Cm-244, etc. The test experiments have demonstrated the capability of measuring the neutron capture cross section of Cm-244 with a sample mass of less than 1mg. We will report preliminary results of the initial experiments, and discuss the new capability. [Preview Abstract] |
Saturday, October 17, 2009 3:45PM - 4:00PM |
LC.00008: Measurements of neutron capture cross sections using a NaI(Tl) spectrometer at the J-PARC MLF neutron nucleus reaction instrument Tatsuya Katabuchi, Masayuki Igashira, Motoharu Mizumoto, Kazuyoshi Furutaka, Shinji Goko, Hideo Harada, Atsushi Kimura, Tadahiro Kin, Fumito Kitatani, Mitsuo Koizumi, Shoji Nakamura, Masayuki Ohta, Masumi Oshima, Yosuke Toh, Michihiro Furusaka, Fujio Hiraga, Takashi Kamiyama, Koich Kino, Yoshiaki Kiyanagi, Toshiyuki Fujii, Jun-ichi Hori, Koichi Takamiya A project to measure neutron capture cross sections of minor actinides and long-lived fission fragments have been started at the neutron nucleus reaction instrument (NNRI) in the Materials and Life science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). We have installed a NaI(Tl) spectrometer in NNRI to detect neutron capture gamma-rays from a sample. Preliminary experimental results will be described. [Preview Abstract] |
Saturday, October 17, 2009 4:00PM - 4:15PM |
LC.00009: Photonuclear Physics at Lawrence Livermore National Lab M.S. Johnson, C.A. Hagmann, J.M. Hall, D.P. McNabb, J.H. Kelley, E. Kwan, G. Rusev, A.P. Tonchev, H.R. Weller, S.L. Hammond National security and international safeguards programs have expressed interest in developing photon sources and detection systems to detect and/or isotopically map shipping containers, fuel assemblies, and waste barrels for special nuclear material (SNM). Current detection systems include basic radiography that gives a density silhouette of a container's contents. Other detection systems include passive arrays that are susceptible to background contamination. Current assay systems use destructive methods to determine isotopic content in fuel rods. This presentation will highlight some of the ambitious efforts at LLNL to exploit processes such as nuclear resonance fluorescence and other photonuclear processes to detect SNM, directly assay fuel rods and waste barrels, and isotopically map configurations of containers. This presentation will include benchmarking measurements at the HIGS facility to characterize detection systems and developing photon sources and recent and ongoing scientific measurements. [Preview Abstract] |
Saturday, October 17, 2009 4:15PM - 4:30PM |
LC.00010: Simulation of a gamma reaction history (GRH) detector for use at the National Ignition Facility (NIF) Elliot Grafil, Jonathan Toebbe Reaction history measurements are critical to diagnosing inertial confinement fusion (ICF) implosions. As such they will be essential components of the National Ignition Facility (NIF) diagnostics. One proposed method to record the reaction history is the construction of a gamma-sensitive gas Cerenkov detector. An array of these Cerenkov detectors can be used to discriminate between the different gamma ray energies produced during the ICF implosion. These fusion gammas are converted to optical photons for collection by fast recording systems. We have simulated the gamma reaction history (GRH) detector under development at NIF and LANL using Geant4. Our simulations have been used to determine energy cut-off ranges for photon production in various gases, optimizing converter material and thickness, and discriminating between proposed detector geometries in order to minimize the temporal spread of the signal. [Preview Abstract] |
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