Resonance Measurements at RPI Ezekiel Blain Research Scientist

Resonance Measurements at RPI Ezekiel Blain Research Scientist Rensselaer Polytechnic Institute, Troy, NY, 12180 Compound Nuclear Reactions Workshop 2018, Sept. 24 -28, 2018, Berkeley, California 1

Overview • Introduction to Resonances – What is a resonance – Why parameterize resonances • RPI LINAC Center – LINAC specifications – Current experimental capabilities • Experimental Results – Capture/Transmission – Scattering – Fission 2

What is a Resonance? • • Resonances occur when the combined energy of the incident particle and the reaction Q value is equal to a specific energy level in the compound nucleus. A resonance results in a large increase in cross section at specific incident particle energies Our understanding of physics is not sufficient to predict the energies of the resonances, their strength, or other quantum numbers (spin, parity, angular momentum) We do have a formalism to describe the shape of a resonance as a function of energy 3

Why parameterize the resonances? • Parametrization advantages: – – Enables temperature (Doppler) broadening Saves space Preserves unitarity Allows for extrapolation into unresolved resonance region • Use resonance analysis codes – SAMMY (ORNL) – REFIT (Moxon, UK) – CONRAD (NEA, France) • Reconstruct the cross section using, NJOY, AMPX , etc. 4

Where is the RPI LINAC ? • It is on the highest point in Troy, NY RPI Campus Flight Stations LINAC NES Offices 5

The RPI LINAC Facility Electron LINAC Neutron Production Target Large Target Room Detection Stations at: 15 m to 250 m New teaching Lab Lead Slowing Down Spectrometer 6

LINAC Specifications Three Sections (Low Energy Port) Electron 5 to 25 Me. V Energy Pulse Width Peak Current 25 to over 60 Me. V 6 to 5000 ns 3 A (short pulse: 6 to 50 ns) 400 m. A (long pulse: 50 to 5000 ns) Average 10 kw@ 17 Me. V, 5000 ns Power Peak Dose >1011 Rads/sec (in Silicon) Rate Neutron Production Nine Sections (High Energy Port) n/a Pulse Single pulse to 500 pps (short pulse) Repetition Single pulse to 300 pps (long pulse) Rate >10 kw@ 60 Me. V, 5000 ns n/a ~4 X 1013 neutrons/sec Single pulse to 500 pps (short pulse) Single pulse to 300 pps (long pulse) 7

Capability Matrix • RPI capability matrix for Nuclear Data Measurements In development Ke. V Neutron Scattering 8

Current Activity • Time of flight measurements – Resonance Region • • • Capture (0. 01 e. V – 2 ke. V) Transmission (0. 001 e. V – 100 ke. V) Capture to fission ratio (alpha) ke. V capture detector Neutron scattering (E<0. 5 Me. V) – High energy (0. 4 -20 Me. V) • Scattering (30 m flight path) • Transmission (100 m and 250 m flight path) • Prompt Fission Neutron Spectra – High accuracy total cross section measurements using a filtered beam • Lead Slowing Down Spectrometer – – – • Simultaneous measurement of fission cross sections and fission fragment mass and energy distributions using the RPI lead slowing down spectrometer Measurements of energy dependent (n, p) and (n, a) cross sections of nanogram quantities of short-lived isotopes. (collaboration with LANL). Capture cross section measurements Other – Research on medical isotope production – Thermal scattering (S(a, b)) measurements (at SNS in ORNL) 9

Resonance Measurements 10

Resonance Region Detectors Li-Glass Detector at 25 m 2 cm B 4 C Liner (98. 4 atom% 10 B) Sample ~20 liter of Na. I(Tl) Li-Glass Detector at 100 m C 6 D 6 Detector at 45 m 11

Transmission Experiment 1. Sample Out Two Experiments: Neutron Beam Li-Glass Neutron Detector 2. Sample In Neutron Beam Li-Glass Neutron Detector Sample N – Number density [atoms/barn] st – Total cross section 12

Capture Experiments Multiplicity Detector Neutron Beam Gamma Rays Sample The capture Yield: u ne s n tro f – neutron flux h – detection efficiency 13

Resonance Cross Section Measurements and Data Analysis Experiment Data Reduction • • US Cross Section Evaluation Working Group (CSEWG) Users - Evaluated Data Files ENDF/B-VIII Data Analysis 14

155 Gd and 157 Gd - Capture Measurements • Many new resonances were observed Y. -R. Kang, M. W. Lee, G. N. Kim, T. -I. Ro, Y. Danon, D. Williams, G. Leinweber, R. C. Block, D. P. Barry, M. J. Rapp, “Neutron Capture Measurements and Resonance Parameters of Gadolinium”, Nuclear Science and Engineering, Volume 180, Number 1, May 2015. 15

High Resolution Transmission Detector • Modular Li-Glass detector at 100 m flight path – Extends our capabilities to the unresolved resonance region 6 Li-Glass – Measurement of 95, 96, 98, 100 Mo completed. LINAC Target Room 100 m flight station Neutron Beam 16

Mo Isotopes in the Resonance Region, 100 m Flight Path • Resonance parameters analysis (transmission only) was completed for Mo-95 and 96. • Data provide information to extend the resolved resonance region of several isotopes R. Bahran, D. Barry, G. Leinweber, M. Rapp, R. Block, A. Daskalakis, B. Mc. Dermott, S. Piela, E. Blain, Y. Danon, “Isotopic Mo Neutron Total Cross Section Measurements in the Energy Range 1 to 620 ke. V”, Nuclear Data Sheets, Volume 119, Pages 137139, May 2014 17

235 U Capture & Fission Yield Data - Epithermal Measurement • Challenges: • Normalization • False capture due to neutron scattering Ø Normalize experimental fission yield to a resonance Solve for k 1 @ 19. 3 e. V res Ø Use two equations for predominantly capture and fission resonances @ 19. 3 e. V res @ 11. 7 e. V res Ø Solve the two equations for k 2 and k 3 ► Need 2 resonances with known parameters ◄ • Provided data to address WPEC subgroup 29 report • The data were used in the U-235 CIELO evaluation which was adopted to ENDF-8. 0 “Uranium-235 Capture Cross-section in the ke. V to Me. V Energy Region” 18

Comparing 235 U Fission and Capture with Evaluations • Fission is in excellent agreement with evaluations • Capture data has up to 8% multiple scattering that must be taken into account during the analysis • Capture error is about 8% • 0. 4 -1 ke. V capture data is closer to ENDF/B-7. 0 • 1 -2 ke. V ENDF/B 7. 0 too high JENDL 4. 0 too low. • E>1 ke. V data is slightly higher than evaluations but within errors. 19

Comparing 235 U fission and capture with ENDF-8. 0 • ENDF 8. 0 is a great improvement from ENDF 7. 1 Y. Danon, D. Williams, R. Bahran, E. Blain, B. Mc. Dermott, D. Barry, G. Leinweber, R. Block and M. Rapp, “Simultaneous Measurement of 235 U Fission and Capture Cross Sections From 0. 01 e. V to 3 ke. V Using a Gamma Multiplicity Detector”, Nuclear Science and Engineering, vol. 187, no. 3, pp. 291 -301, 2017. 20

Mid-Energy Capture Detector System Overview • 4 C 6 D 6 detector modules manufactured by Eljen Technology • Low mass, low neutron sensitivity design • Located at 45 m flight path in newly constructed flight station • Measurements made from 1 e. V to 1 Me. V • Requires a weighting function 21

56 Fe Results – MCNP Comparison • Possible unresolved or intermediate structure may account for higher data yields from 600 -850 ke. V (selfshielding) • ENDF/B VII. 1 overcompensates with its background treatment, JEFF has no background treatment. • Above 850 ke. V, the data agree with the 3 evaluations presented. • ENDF 8. 0 uses the IAEA evaluation for Fe-56 Mc. Dermott, Brian, Blain, Ezekiel, Thompson, Nicholas, Weltz, Adam, Youmans, Amanda, Danon, Yaron, Barry, Devin, Block, Robert, Daskalakis, Adam, Epping, Brian, Leinweber, Gregory and Rapp, Michael, “ 56 Fe capture cross section experiments at the RPI LINAC Center”, EPJ Web Conf. , vol. 146, pp. 11038, 2017. 22

Lead Slowing Down Spectrometer 23

Lead Slowing-down Spectrometer at RPI 67 tons of Pb • Tantalum target in the center produces neutrons. 180 cm Flux Monitor • Neutrons scatter elastically with the Pb. • About 103 -104 times higher flux than an equivalent flight path TOF experiment (5. 6 m). He Filled Drift Section 180 cm • Neutrons can pass through the same position several times. Flux Monitor Neutron Source (He cooled Ta Target) Ti Window LEAD Flux Monitor Vacuum Electron Beam Fission Chamber (60 cm from corner) Crossed I beam + Li 2 CO 3 24

Fission Fragment Kinematics Experiments Double Gridded Fission Chamber Collaboration with LANL • Fission cross sections. • (n, a), (n, p) measurements on small samples. Multiparameter DAQ 25

Fission symmetry in resonance clusters Symmetry in resonances relative to thermal C. Romano, Y. Danon, R. Block, J. Thompson, E. Blain, E. Bond, “Fission Fragment Mass And Energy Distributions As A Function of Neutron Energy Measured In A Lead Slowing Down Spectrometer”, Phys. Rev. C, 81, 014607 (2010). 26

239 Pu - Results E<0. 1 e. V (region 1) 27

Selected Nuclear Data Related Publications • • Fission Ø Ø LSDS Ø Ø • Ø Ø • Y. -R. Kang, M. W. Lee, G. N. Kim, T. -I. Ro, Y. Danon, D. Williams, G. Leinweber, R. C. Block, D. P. Barry and M. J. Rapp, “Neutron Capture Measurements and Resonance Parameters of Gadolinium”, Nucl. Sci. Eng. , vol. 180, no. 1, pp. 86 -116, 2015. G. Leinweber, D. P. Barry, M. J. Trobovich, J. A. Burke, N. J. Drindak, , HD Knox, RV Ballad, R. C. Block, Y. Danon, L. I. Severnyak, “Neutron Capture and Total Cross-Section Measurements and Resonance Parameters of Gadolinium”, . Nuc. Sci Eng. 154, 261 -279 (2006). Dy • Shin, S. G. , Kye, Y. U. , Namkung, W. , Cho, M. H. , Kang, Y. -R. , Lee, M. W. , Kim, G. N. , Ro, T. -I. , Danon, Y. , Williams, D. , Leinweber, G. , Block, R. C. , Barry, D. P. and Rapp, M. J. , “Neutron capture measurements and resonance parameters of dysprosium”, Eur. Phys. J. A, vol. 53, no. 10, pp. 203, 2017. R. C. Block, M. C. Bishop, D. P. Barry, G. Leinweber, R. V. Ballad, J. A. Burke, M. J. Rapp, Y. Danon, A. Youmans, N. J. Drindak, G. N. Kim, Y. -R. Kang, M. W. Lee and S. Landsberger, “Neutron transmission and capture measurements and analysis of Dy from 0. 01 to 550 e. V”, Prog. Nucl. Energy, vol. 94, pp. 126 -132, jan 2017. Nb Ø N. J. Drindak, J. A. Burke, G. Leinweber, J. A. Helm, J. G. Hoole, R. C. Block, Y. Danon, R. E. Slovacek, B. E. Moretti, C. J. Werner, M. E. Overberg, S. A. Kolda, M. J. Trobovich, D. P. Barry, “Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Niobium”, Nuc. Sci Eng. 154, 294 -301 (2006). Nd Ø Ø • M. J. Rapp, Y. Danon, F. J. Saglime, R. M. Bahran and D. G. Williams, G. Leinweber, D. P. Barry and R. C. Block, “Beryllium and Graphite Neutron Total Cross Section Measurements from 0. 4 to 20 Me. V”, Nuclear Science and Engineering, Vol. 172, No. 3. Pages 268 -277, November 2012 (2012). Y. Danon , R. C. Block, M. J. Rapp, and F. J. Saglime, G. Leinweber, D. P. Barry, N. J. Drindak and J. G. Hoole, “Beryllium and Graphite High Accuracy Total Cross-Section Measurements in the Energy Range from 24 ke. V to 900 ke. V”, Nuclear Science And Engineering, 161, 321– 330, (2009) Gd • • G Leinweber, DP Barry, JA Burke, NJ Drindak, RC Block, Y Danon, BE Moretti, “Resonance Parameters and Their Uncertainties Derived from Epithermal Neutron Capture and Transmission Measurements of Elemental Molybdenum”, Nuc. Sci. Eng. , 164, 287 -303, (2010). G. Leinweber, D. P. Barry, J. A. Burke(ret. ), N. J. Drindak, R. C. Block, Y. Danon, B. E. Moretti, “Measurements of elemental molybdenum and resonance parameter analysis”, International Conference on Nuclear Data for Science and Technology (ND 2007), April 22 -27, Nice, France, (2007) C & Be Ø • A. M. Daskalakis, E. J. Blain, B. J. Mc. Dermott, R. M. Bahran, Y. Danon, D. P. Barry, R. C. Block, M. J. Rapp, B. E. Epping and G. Leinweber, “Quasi-differential elastic and inelastic neutron scattering from iron in the Me. V energy range”, Annals of Nuclear Energy, vol. 110, pp. 603 - 612, 2017 A. M. Daskalakis, R. M. Bahran, E. J. Blain, B. J. Mc. Dermott, S. Piela, Y. Danon, D. P. Barry, G. Leinweber, R. C. Block, M. J. Rapp, R. Capote and A. Trkov, “Quasi-differential neutron scattering from 238 U from 0. 5 to 20 Me. V”, Ann. Nucl. Energy, vol. 73, pp. 455 -464, 2014. Mo Ø • J. T. Thompson, T. Kelley, E. Blain, R. C. Haight, J. M. O'Donnell, Y. Danon, “Measurement of (n, α) reactions on 147 Sm and 149 Sm using a lead slowing-down spectrometer”, Nuclear Instruments and Methods in Physics Research Section A, Volume 673, Pages 16 -21, 1 May (2012) C. Romano, Y. Danon, R. Block, J. Thompson, E. Blain, E. Bond, “Fission Fragment Mass And Energy Distributions As A Function of Neutron Energy Measured In A Lead Slowing Down Spectrometer”, Phys. Rev. C 81, 014607 (2010). Neutron Scattering Ø • E. Blain, A. Daskalakis, R. C. Block and Y. Danon, “Measurement of prompt fission neutron spectrum for spontaneous fission of 252 Cf using γ multiplicity tagging”, Phys. Rev. C, vol. 95, pp. 064615, Jun 2017. Y. Danon, D. Williams, R. Bahran, E. Blain, B. Mc. Dermott, D. Barry, G. Leinweber, R. Block and M. Rapp, “Simultaneous Measurement of 235 U Fission and Capture Cross Sections From 0. 01 e. V to 3 ke. V Using a Gamma Multiplicity Detector”, Nuclear Science and Engineering, vol. 187, no. 3, pp. 291 -301, 2017 D. P. Barry, M. J. Trbovich, Y. Danon, R. C. Block, R. E. Slovacek, G. Leinweber, J. A. Burke, N. J. Drindak, “Neutron Capture and Total Cross-Section Measurements and Resonance Parameter Analysis of Neodymium from 1. 0 e. V TO 500 e. V”, The Tenth International Conference on Radiation Shielding and Radiation Protection & Shielding Topical (ICRS 10 / RPS-2004), Madeira, Portugal, May 9 -14, (2004) D. P. Barry, M. J. Trbovich, Y. Danon, R. C. Block, R. E. Slovacek, G. Leinweber, J. A. Burke, N. J. Drindak, “Neutron Transmission and Capture Measurements and Resonance Parameter Analysis of Neodymium From 1. 0 e. V To 500 e. V”. Nuclear Science And Engineering: 153, 8– 2, (2006) Hf Ø Sm Ø Ø M. J. Trbovich, D. P. Barry, R. E. Slovacek, Y. Danon, R. C. Block, N. C. Francis, M Lubert, J. A. Burke, N. J. Drindak, G. Leinweber, R. Ballad, “Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments” Nuclear Science And Engineering, 161, 303– 320, (2009). S. Wang, M. Lubert, Y. Danon, N. C. Francis, R. C. Block, F. Becvar, M. Krticka, “The RPI multiplicity detector response to g -ray cascades following neutron capture in 149 Sm and 150 Sm”, NIM A 513/3 pp. 585 -595, (2003) Leinweber, G. , Burke, J. A. , Knox, H. D. , Drindak, N. J. , Mesh, D. W. , Haines, W. T. , Ballard, R. V. , Block, R. C. , Slovacek, R. E. , Werner, C. J. , Trbovich, M. J. Barry, D. P. and Sato, T. , “Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Samarium, ” Nuclear Science and Engineering, 142, 1 -21, 2002 28

Thank you for your attention 29