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nacThe Gaerttner LINAC Center
1
Overview Of
Experimental Nuclear Data Capabilities at RPI
Prof. Yaron DANON
Gaerttner LINAC Center Director
Nuclear Engineering Program Director
Rensselaer Polytechnic Institute, Troy, NY, 12180
Workshop for Applied Nuclear Data Activities (WANDA), January 22-24, 2019Elliott School of International affairs at the George Washington University
nacThe Gaerttner LINAC Center
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Outline
• The RPI Gaerttner LINAC Center
– Capabilities
• Examples
– U-235 fission and Capture
– Fe-56 and Fe-nat capture
– H2O transmission
– U-238, Be, Fe, scattering
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Where is the RPI LINAC ?
• It is on the highest point in Troy, NY
LINAC
Flight Stations
NESOffices
RPI Campus
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RPI LINAC History
• The RPI LINAC started operation in December 1961.
• Working “continuously” since.
Graduated over 180 students who utilized the LINAC as part of their graduate thesis research
Many years of accumulated experience
September 1997- LINAC was designated as Nuclear Historic Landmark by the American Nuclear Society
2014 - Started a major refurbishment and upgrade project
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The RPI LINAC Facility
O FFICE
O FFICE
O FFICE
O FFICE
O FFICE
O FFICEO FFICEO FFICEO FFICE
SERVICE RO OM
BUTLER
BR
BR
SH OP A REA
BUILD IN G
HO T
LA BO RA TORY
D AR K
RO O MCO N TRO L
RO O M N EEP LA B
STO RA G E
RO O M
RO O M
TA RG ET
A CC ELERA TO R
RO O M
RO O M
MO DU LA TO R
N ICE
LA B
RO O M
TA RG ET
A CC ELERA TO R
RO O M
N
GAERTTNER LINAC LABORATORY
INSTITUTE
RENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTE
RENSSELAER POLYTECHNIC
HO T
RO O M
TA RG ET
A CC ELERA TO R
RO O M
N ICE
LA B
RO O M
TA RG ET
A CC ELERA TO R
RO O M
25-M ETE R
ST ATI ON
100-M ETE R 250-M ETE R
ST ATI ON
N
GAERTTNER LINAC LABORATORY
INSTITUTE
RENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTE
RENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTE
RENSSELAER POLYTECHNIC
30 PO RT
ENERG Y
A NA LYZIN G
MA GN ET
He FLIG HT
PA TH
15-M ETE R
D ET EC TOR
TR AN SMI SSIO N
CA PTU RE
D ETECT OR
D ETECT OR
TRA N SMISSION
A UX ILLA RY
EQU IPMEN T
RO O M
Bent/Tilt
Focus
SPE CT ROM ETE R
LE AD SL OW IN G D OW N
EAS T
45-M ETE R
ST ATI ONST ATI ON
WEST
Neutron Production Target
Large Target Room
Detection Stations at:15m to 250m
Lead Slowing Down Spectrometer
Electron LINAC
New teaching Lab
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Capability Matrix
KeV Neutron Scattering
In development
10-3 10-2 10-1 100 101 102 103 104 105 106 107
PAC
BBT/PAC C6D6 Capture Detector
ETT
LSDS fission sf / fragment dist.
PFNS
Fast/LiGlass ArrayBT
BBT/PACMultiplicity Detector
Fission
PAC 100m LiGlass Detector
Li-Glass Array
BBT
ETT
BT
BT
BBT
ETT
Scattering
Capture
Neutron Energy [eV]
Transmission
15m LiGlass Detector
25m/30m LiGlass Detector
250m EJ301
Multiplicity Detector
Multiplicity Detector
EJ301 Array
RPI LINAC - Nuclear Data Measurement Capabilities 2019
BBT/PAC/BBT
ETT
Targets
ETT- Enhanced Thermal Target PAC - PacMan Target
BBT - Bare Bounce Target PN - Photoneutron target
BT- Bare Target on Axis
Multiplicity Detector
Multiplicity Detector
Multiplicity Detector
Photoneutons
EJ301 ArrayLi-Glass ArrayPN Photoneutron target
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Neutron Production TargetsEnhanced Thermal Target (ETT)Bare Bounce Target (BBT)
C-Shaped target
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Detectors
Transmission
Capture/multiplicity
ScatteringPFNS @ 30m
15m- 30m
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Current Activity
• Time of flight measurements– Resonance Region
• Capture (0.01 eV – 2 keV)• Transmission (0.001 eV – 100 keV)• Capture to fission ratio (alpha)• keV capture detector• Neutron scattering (E<0.5 MeV)
– High energy (0.4-20 MeV)• Scattering (30 m flight path)• Transmission (100 m and 250 m flight path)• Prompt Fission Neutron Spectra• Photoneutron 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)
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Resonance Region
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Resonance Region Detectors
Li-Glass Detector at 25m2 cm B4C Liner (98.4 atom% 10B)
Sample
~20 liter of NaI(Tl)Li-Glass Detector at 100m
C6D6 Detector at 45m
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235U Capture & Fission Yield Data
• Challenges:• Normalization• False capture due to neutron scattering
Normalize experimental fission yield to a resonance
Use two equations for predominantly capture and fission resonances
Solve the two equations for k2 and k3
► Need 2 resonances with known parameters ◄
f
ENDF
f YkY 1
86.0
f
ENDF YkkYkY 222 132
63.0
f
f
ENDF YkkYkY 111 132
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10 15 20 25 30 35 40 45 500.00
0.05
0.10
0.15
0.20
0.25
0.30
Yie
ld
RPI Capture
Sammy CaptureNormalization
Yie
ldf
Neutron Energy [eV]
RPI Fission
Sammy Fission
600 700 800 900 10000.00
0.01
0.02
0.03
0.00
0.01
0.02
0.03
Yie
ldf
Neutron Energy [eV]
RPI Fission
Sammy Fission
Yie
ld
RPI Capture
Sammy Capture
Solve for k1 @ 19.3 eV res
@ 19.3 eV res@ 11.7 eV res
63.0
f
• Provided data to address WPEC subgroup 29 report “Uranium-235 Capture Cross-section in the keV to MeV Energy
Region”
• The data were used in the U-235 CIELO evaluation which was adopted to ENDF-8.0
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0.005
0.01
0.1
0.2
100 10000.005
0.01
0.1
0.2
Y
Capture
RPI - Experiment
ENDF/B-7.0
JENDL4
SAMMY ENDF7 Capture
Yf
Energy [eV]
Fission
RPI - Experiment
ENDF/B-7.0
JENDL4
SAMMY ENDF7 Fission
Comparing 235U 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 keV capture data is closer to ENDF/B-7.0
• 1-2 keV ENDF/B7.0 too high JENDL 4.0 too low.
• E>1 keV data is slightly higher than evaluations but within errors
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500 1000 1500 2000 25000.005
0.010
0.015
0.020
0.025
0.030
Y
Energy [eV]
RPI - Experiment
JENDL4+MS
SAMMY ENDF7 Capture
END of RRR
in ENDF/B7.0
Comparing 235U 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 keV capture data is closer to ENDF/B-7.0
• 1-2 keV ENDF/B7.0 too high JENDL 4.0 too low.
• E>1 keV data is slightly higher than evaluations but within errors
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Comparing 235U Fission and Capture
with ENDF-8.0
• ENDF 8.0 is a great improvement from ENDF 7.1
500 1000 1500 2000 2500 30001000.00
0.01
0.02
0.03
0.04
0.05 Experiment norm to ENDF 7.1
MCNP ENDF 7.1
Experiment norm to ENDF 8.0
MCNP ENDF 8.0
Captu
re Y
ield
Energy [eV]
500 1000 1500 2000 2500 30001000.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09 Experiment norm to ENDF 7.1
MCNP ENDF 7.1
Experiment norm to ENDF 8.0
MCNP ENDF 8.0
Fis
sio
n Y
ield
Energy [eV]
Y. Danon, D. Williams, R. Bahran, E. Blain, B. McDermott, D. Barry, G. Leinweber, R. Block and M. Rapp,“Simultaneous Measurement of 235U Fission and Capture Cross Sections From 0.01 eV to 3 keV Using aGamma Multiplicity Detector”, Nuclear Science and Engineering, vol. 187, no. 3, pp. 291-301, 2017.
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Fe and Fe-nat KeV Neutron Capturemid-energy capture detector system overview
• 4 C6D6 detector modules
manufactured by Eljen
Technology
• Low mass, low neutron
sensitivity design
• Located at 45m flight path in
newly constructed flight station
• Measurements made from 1 eV
to 1 MeV
• Requires a weighting function
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• Possible unresolved or intermediate structure may account for higher data yields from 600-850 keV (self-shielding)
• ENDF/B VII.1 overcompensates with its background treatment, JEFF has no background treatment.
• Above 850 keV, the data agree with the 3 evaluations presented.
• ENDF 8.0 follows uses the IAEA evaluation for Fe-56
56Fe Results – MCNP Comparison
600 800 1000 1200 1400 1600 1800 20000.0000
0.0005
0.0010
600 800 1000 1200 1400 1600 1800 20000.0000
0.0005
0.0010
800 1000 1200 1400 1600 1800 20006000.0000
0.0005
0.0010
Ye
xp 56Fe
ENDF/B-VII.1
Ye
xp 56Fe
JEFF-3.2
Ye
xp
Energy [keV]
56Fe
IAEA
McDermott, Brian, Blain, Ezekiel, Thompson, Nicholas, Weltz, Adam, Youmans, Amanda, Danon, Yaron, Barry,Devin, Block, Robert, Daskalakis, Adam, Epping, Brian, Leinweber, Gregory and Rapp, Michael, “56Fe capture crosssection experiments at the RPI LINAC Center”, EPJ Web Conf., vol. 146, pp. 11038, 2017.
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Lead Slowing Down Spectrometer
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VacuumTi Window
ElectronBeam
He Filled Drift Section
Neutron Source(He cooled Ta Target)
LEAD
Crossed I beam + Li2CO3
180 cm
18
0 c
m
Fission Chamber
Flux Monitor
Flux Monitor
Flux Monitor
•Tantalum target in the center produces neutrons.
•Neutrons scatter elastically with the Pb.
•Neutrons can pass through the same position several times.
•About 103-104
times higher flux than an equivalent flight path TOF experiment (5.6m).
(60 cm from corner)
Lead Slowing-down Spectrometer at RPI
67 tons of Pb
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10-1 100 101 102 103 104 5x104102
103
104
105
106
Ra
te [cp
s]
Energy [eV]
10 Mil Ta Sample
Simulation, ENDF/B-VII.1
Simulation, JEFF 3.2
Simulation, JENDL 4.0
Measurement
Sample impurities simulated with
ENDF/B-VII.1 libraries
102 103 104 5x1041.0x105
1.5x105
2.0x105
2.5x105
3.0x105
3.5x105
4.0x105
4.5x105
5.0x105
Ra
te [
cp
s]
Energy [eV]
10 Mil Ta Sample
Simulation, ENDF/B-VII.1
Simulation, JEFF 3.2
Simulation, JENDL 4.0
Measurement
Detector 1
Results – Ta Capture• Good agreement up to 300 eV
– Some disagreement in the ENDF/B-VII unresolved resonance region
– RPI is Working on improving Ta RRR cross section in a project funded by NCSP
URR in ENDF
URR in JEFF and JENDL
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102 103 104 5x104
106
105
2x106
Ra
te [cp
s]
Energy [eV]
0.6 mm Silver Sample
Simulation, ENDF/B-VII.1
Simulation, JEFF 3.2
Simulation, JENDL 4.0
Measurement10-1 100 101 102 103 104 5x104
104
105
106
103
5x106
Ra
te [
cp
s]
Energy [eV]
0.6 mm Silver Sample
Simulation, ENDF/B-VII.1
Simulation, JEFF 3.2
Simulation, JENDL 4.0
Measurement
Results – Ag Capture
• Large differences between
libraries above 1 keV160 170 180 190 200 210 220 230 240
0.0
2.0x102
4.0x102
6.0x102
8.0x102
1.0x103
1.2x103
Cro
ss S
ectio
n [
ba
rns]
Energy [eV]
107Ag Cross section
ENDF/B-VII.1
JEFF 3.2
JENDL 4.0
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Fast Region
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Collimation Collimation Collimation
Water
Cooled Ta
Target
SampleEJ-301 Liquid Scintillator
Modular Detector
99.93m
91 cm
60 cm
High Energy Transmission Experimental
Setup
Graphite Samples
33
13
7 5
Nominal thickness in cm
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Zr Total Cross Section Measurements (0.5-20 MeV)
• Used low Hf (less than 100 ppm) Zr metal
• ENDF/B 6.8 seems like a better fit for E<16 MeV
• New partially resolved structure below 2.0 MeV
• Data can be used to improve the unresolved resonance region evaluation.
0.5 1.0 1.5 2.0 2.5 3.03
4
5
6
7
8
9
10
11
12
st [
ba
rn]
Energy [MeV]
RPI Experiment Arpil - May 2008
ENDF/B-6.8
ENDF/B-7.0
JEFF 3.1
JENDL 3.3
2 4 6 8 10 12 14 16 18 203.0
3.5
4.0
4.5
5.0
5.5
st [
barn
]
Energy [MeV]
RPI Experiment Arpil - May 2008
ENDF/B-6.8
ENDF/B-7.0
JEFF 3.1
JENDL 3.3
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U-238, Fe, Be scattering
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Elastic / Inelastic Neutron Scattering
• Important for neutron (and gamma) transport calculations
– Applications: criticality, reactors, shielding, oil well logging, SNM
detection, others…
• Quantities of interest
– Neutron cross section and angular distribution
– Gamma production from inelastic scattering and its angular distribution
– Neutron energy transfer (requires inelastic levels)
• Energy range of interest - from URR to fast
– In the RRR, resonance parameters can be used to calculate both cross
sections and angular distribution.
– URR sometimes difficult for model calculations experimental data is
needed.
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Current Evaluated Scattering Data
• Hard to measure thus evaluate
– Large uncertainties
• Example: “well known” U-238
Elastic angular distribution En=0.9 MeV Notice ENDF-7.1 at back angles (n,inl) cross section
~10%ENDF-7.1 is very low
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Scattering Detection System:
Experimental Setup
• Detector Array– Eight EJ301 Liquid Scintillation Detectors
– Eight A/D channels
– Pulse Shape discrimination in TOF
• Measures neutrons scattered from the sample at different angles
• Measured scattered neutron energy 0.5 MeV - 20 MeV
• Results are compared with a Monte Carlo simulation of the system
A. M. Daskalakis, E. J. Blain, B. J. McDermott, 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 MeV energy range”, Annals of Nuclear Energy, vol. 110, pp. 603 - 612, 2017.
A.M. Daskalakis, R.M. Bahran, E.J. Blain, B.J. McDermott, S. Piela, Y. Danon, D.P. Barry, G. Leinweber, R.C. Block, M.J. Rapp, R. Capote, A. Trkov, “Quasi-differential neutron scattering from 238U from 0.5 to 20 MeV”, Annals of Nuclear Energy, Volume 73, Pages 455-464, November 2014.
D. P. Barry, G. Leinweber, R. C. Block, and T. J. Donovan, Y. Danon, F. J. Saglime, A. M. Daskalakis, M. J. Rapp, and R. M. Bahran, “Quasi-differential Neutron Scattering in Zirconium from 0.5 MeV to 20 MeV”, Nuclear Science and Engineering, 174, 188–201, (2013).
F.J. Saglime, Y. Danon, R.C. Block, M.J. Rapp, R.M. Bahran, G. Leinweber, D.P. Barry and N.J. Drindak, “A system for differential neutron scattering experiments in the energy range from 0.5 to 20 MeV”, Nuclear Instruments and Methods in Physics Research Section A, 620, Issues 2-3, Pages 401-409, (2010)
238U Sample
EJ-301 Detectors
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238U Scattering at 153 deg• Graphite experiment shows good
agreement with the simulations,
• 238U shows differences near 1 MeV
• Newer IAEA evaluation provides the best
fit
• ENDF/B-VII.1 needs improvement
500 800 1200 1600 2000 2400 2800 31280
1000
2000
3000
4000
50000.10.51251020
Detector 3
153o
Week 2
Energy [MeV]
Co
un
ts
Time of Flight [ns]
Uranium Data
ENDF/B-VII.1
JEFF-3.2
JENDL-4.0
IAEA-ib34
800 1200 1600 2000 2400 2800500 31280
2000
4000
6000
8000
10000
12000
140000.10.51251020
Energy [MeV]
Co
un
ts
Time of Flight [ns]
Graphite Data
MCNP Results
153 deg
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Fe Scattering Measurement - Setup
The neutron beam diameter is smaller than the sample size.
EJ-301 Liquid Scintillator Neutron Detectors
Fe SampleDimensions 77.0 x 152.6 x 32.2 mm
Evacuated Flight Tube
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Iron Scattering
• Measured the total scattering and compared with detailed simulation
• Method was verified with graphite
Resonance Region
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NatFe Elastic/Inelastic Scattering – example data
1550 1600 1650 1700 1750 1800 1850 19000
500
1000
1500
2000
2500
3000
350011.41.51.61.71.81.92
Detector 2
77o
Week 2
Energy [MeV]
Co
un
ts
Time of Flight [ns]
Nat
Fe Data (MWD)
ENDF/B-VII.1
JEFF-3.2
JENDL-4.0
• The JENDL-4.0 evaluation overestimated the elastic signal at 77°
• It seems that the I/E ratio for JENDL is low because the elastic scattering is too
high.
1.4 1.6 1.8 2.00.0
0.4
0.8
1.2
1.6
I/E Ratio JEFF-3.2
I/E Ratio ENDF/B-VII.1
I/E Ratio JENDL-4.0Nat
Fe Ratio (Measured)
I/E
Ratio
Incident Neutron Energy [MeV]
Detector 2 at 77o
Elastic Scattering
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Experimental Setup at LANL
• Motivation U-235 and Pu-239
• Relatively simple experiments
• Benchmark the simulation physics and
nuclear data.
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Preliminary Results – 235U and 239Pu at 60 deg• 49.5 g of U enriched to 93% 235U,
• 24g of 239Pu
239Pu 235U
Graphite
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Preliminary Results – 235U and 239Pu at 150 deg• Similar results at back scattering angles, possible issues with both 235U and 239Pu
239Pu 235U
Graphite
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For a full list of publications visit: http://www.rpi.edu/~danony