1 / 28

Robert Haight Los Alamos National Laboratory IAEA Technical Meeting on IFMIF FZK Karlsruhe

LANSCE Nuclear Data Measurement Capabilities. Robert Haight Los Alamos National Laboratory IAEA Technical Meeting on IFMIF FZK Karlsruhe October 4-6, 2005. Ref: LA-UR-05-5228. Outline. LANSCE Capabilities Source characteristics Instruments People

paniz
Download Presentation

Robert Haight Los Alamos National Laboratory IAEA Technical Meeting on IFMIF FZK Karlsruhe

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LANSCE Nuclear Data Measurement Capabilities Robert Haight Los Alamos National Laboratory IAEA Technical Meeting on IFMIF FZK Karlsruhe October 4-6, 2005 Ref: LA-UR-05-5228

  2. Outline • LANSCE Capabilities • Source characteristics • Instruments • People • Missions (funding sources for LANSCE) • Improvements planned

  3. Isotope Production Facility H+ Source Drift Tube Linear Accelerator H- Source Line D 9 10 11A/B ER-1 7 12 8 6 13 Target 1 14 15 4 3 16 1 2 ER-2 5 Nuclear physics experiments at LANSCE use neutrons at four locations: Line B, Lujan Center, Target 2 and Target 4. Proton Radiography Line B NRAD, Ultra-Cold Neutrons Area A (future MTS) Side-Coupled Linear Accelerator Proton LSDS Lujan Center En < 500 keV PSR Weapons Neutron Research Facility 0.1 MeV < En < 600 MeV Target 2 GEANIE 120L 90R DANCE 60R FIGARO 90L 30R 15R Fission 30L 15L N,Z

  4. Proton beam WNR -- Target Specifications • Target-2 (Blue Room) • Up to ~ 1 µA proton beam • Proton induced reactions • 6 flight paths • Proton irradiations • Lead slowing-down • spectrometer (LSDS) • Target-4 • 4 µA proton beam for high-energy neutron spallation source. Typical operation is 35,000 pulses/sec with 1.8 µsec spacing. • 6 neutron flight paths • Neutron induced reactions • Energy spectrum depends on flight-path angle • Determine energy of neutron by time-of-flight • Neutron irradiations

  5. Lujan Center -- Moderated spallation source 800 MeV protons + tungsten -> fast neutrons (0.1 to 800 MeV) … then fast neutrons + H2O - > slower neutrons (subthermal to 1 MeV) DANCE

  6. LANSCE neutron spectra cover energies from cold to several hundred MeV Moderated source (Lujan) Unmoderated source (WNR)

  7. 10 eV +9 10 10 10 10 -8 -4 0 +4 ultracold cold thermal epithermal fast Lujan (3) Target 2 (1 to 6) WNR(6) Area B(1) Neutrons at LANSCE span 16 orders of magnitude in energy Area & (number of flight paths) LSDS

  8. Comparison of Lujan and WNR with ORELA • Neutrons on sample From: Michaudon and Wender (1990)

  9. Comparison with e.g. ORELA shows complementarity

  10. Resolution comparisons for epithermal neutrons From Koehler: NIM A460, 352 (2001)

  11. LANSCE Nuclear Physics Instruments • Fast neutrons (En > 0.1 MeV) • GEANIE – gamma-ray detector array of 26 HPGe detectors • FIGARO – neutron detector array • Frisch-grid fission ion chamber to measure cross sections, fission product yields, total energy released • (n,z) instrument – silicon + CsI(Tl) for H and He measurements • Total cross sections – (presently not active) • Epithermal • DANCE – 4-pi calorimeter for neutron capture- 160 BaF2 detectors • Frisch-grid fission ion chamber • LSDS: fission chambers to measure fission cross sections on ultra-small samples

  12. FIGARO (n,xn+g) Nuclear data measurements at LANSCE are made with several instruments DANCE (n,g) GEANIE (n,xg) Fission N,Z (n,charged particle) LSDS Double Frisch-gridded fission chamber; also standard fission ion chamber Total cross sections

  13. collimation shutter tungsten slower faster gamma target pulsed neutrons neutrons rays 800 MeV proton neutrons beam 15 meters Most measurements use the time-of-flight technique Time of flight over the flight path identifies the energy of the neutron that induces the reaction WNR Reaction and detector area En ~ v2~ 1/t2 (nonrelativistic) • Repetition rate • “Gamma” flash • Available flight paths • Backgrounds • Important characteristics: • Neutron flux at sample • Flux spectrum • Time resolution

  14. WNR neutron total cross sections were measured with ~ 1% absolute uncertainty in the 5 – 560 MeV range From: Finlay et al. (1993) and Abfalterer et al. (2001)

  15. GEANIE: New data significantly improve the 193Ir(n,n’)193mIr cross section database GEANIE LLNL/LANL

  16. FIGARO (n,f+xn) FIGARO: Measurements quantify how the fission neutron spectrum varies with incident neutron energy 238U(n,f) average neutron energy Agreement with Los Alamos Model is good below 20 MeV Los Alamos Model * Fission chamber From: Ethvignot et al., Phys. Lett. B575, 221 (2003).

  17. FIGARO: Neutron emission spectra are measured by triggering on gamma rays FIGARO (n,xn+g) * BaF2 HPGe From: Rochman et al. (2004)

  18. (n,z) ( = hydrogen and helium production): LANSCE data differentiate among different evaluations From: Haight, ANS meeting (2004)

  19. DANCE: 237Np(n,) data are part of our AFCI program on actinides – sample is 0.44 mg Target: 0.44 mg 237Np in 6.4 mm diameter (1.4 mg/cm2) Technological development: 334 channels of waveform digitizers – process in < 50 ms  ~ 1GB/sec

  20. The Lead Slowing-Down Spectrometer is driven by 800 MeV protons from the PSR Neutron trajectories following the interaction of 1 proton with the tungsten target in the lead cube

  21. LSDS: We can now measure fission cross sections for samples smaller than 10 ng • Ran 1 mA of PSR beam to LSDS – radiation levels < 2 mR/hr outside of Blue Room • Ran PSR at 30 Hz successfully • Measured neutron-induced fission cross section of 239Pu with a sample of 9.87 ng. Results agree with broadened ENDF/B-VI.  New shielding in BR hall  First 30 Hz PSR beam  This meets our goal for measuring the fission cross section of the 235U isomer with a 10 ng sample. • Measured (n,a) cross section with small 6Li sample • DAQ works well in present configuration. Digital filtering under development.  Good prospects for other (n,a) measurements.

  22. Fission cross section measurements are underway for the AFCI program • Extend program of Lisowski and that of Staples & Morley • Measurements both at WNR and at Lujan  data from • thermal to ~ 200 MeV • Double Frisch-gridded ion chamber • – from Hambsch (IRMM, Geel, Belgium) • Data very soon

  23. The LANSCE program in nuclear data attracts researchers from many laboratories • GEANIE – LANL, LLNL, INL, Bruyères-le-Châtel, NC State • FIGARO – LANL, BNL, Bruyères-le-Châtel • N,Z – LANL, Ohio U • DANCE – LANL, LLNL, INL, ORNL, Colorado School of Mines, FZK Karlsruhe, NC State, others • LSDS – LANL, LLNL, BNL, Bruyères-le-Châtel, RPI • Fission – LANL, INL, IRMM (Geel) • Proton – LANL, Georgia Tech • Others – MIT, Kentucky, Kyushu, Harvard,…

  24. The LANSCE program is supported by several funding agencies • NNSA - accelerator and experiments • DOE - Nuclear Energy - Advanced Fuel Cycle Initiative • DOE - Office of Science – Nuclear Physics • LANL internal funds (LDRD)

  25. Some improvements for the future (1) • Improvements in Beam • More beam at WNR (factor of 4 to 6) from improvements in the ion source, better transmission and a longer macropulse length (= higher duty factor) • Permits shorter run time; more experiments • Permits larger micropulse spacing so that frame overlap is less of a problem  go to lower neutron energies At present with 1.8 microsecond spacing • At 9 m  fram overlap at 130 keV and lower • At GEANIE at 20 meters  600 keV • At 90 meters  9.6 MeV • More beam at Lujan (factor of ~2) due to improvements in the ion source • More experiments • Possible shorter pulse length with same current  allows to go to higher neutron energies ( > 100 keV), now limited in resolution by the width of the pulse.

  26. Some improvements for the future (2) • More improvements in beam: PSR-to-WNR • Fills in the region between Lujan and present WNR: 10 keV to a few MeV  of great importance to Advance Reactors and Weapons • Much larger micropulse spacing (16 ms to 2.8 ms) • New WNR target to enhance flux in the 10 keV to a few MeV region • Increase in intensity over Lujan in this region by a factor of > 30

  27. Some improvements for the future (3) • Availability of radioactive samples through IPF • Many more radioactive isotopes for experiments at DANCE and LSDS • Close-by  relatively short-lived isotopes possible • Improvements in instruments • GEANIE – higher efficiency HPGE detectors • FIGARO – complete array to 50 detectors • DANCE – include some HPGe detectors • (n,z) – more detectors to give larger solid angle, more angles • Fission – Mass, charge, energy detection for both fragments in coincidence • Lead Slowing-Down Spectrometer: Dedicated location (?beam line) – so assembly/disassembly not required each time • Integral experiments – like pulsed spheres?

  28. Brief summary of LANSCE Capabilities • Excellent timing for fast neutrons ( < 1 ns at WNR) • High intensity for En < 50 keV (Lujan) and En > 1 MeV (WNR) • Energy range extends to ~ 600 MeV • Low gamma-flash for fast neutrons (WNR) • Many well-characterized instruments • Many flight paths – used simultaneously • Ability to access proton beam directly (e.g. LSDS) • (Ability to do classified experiments) • Many improvements planned in beam and instruments

More Related