experimental capabilities for applied nuclear...
TRANSCRIPT
1nacThe Gaerttner LINAC Center
Experimental Capabilities for Applied Nuclear Science at RPI
Professor, Director Gaerttner LINAC Center Nuclear Engineering Program Director
Department of Mechanical, Aerospace and Nuclear EngineeringRensselaer Polytechnic Institute, Troy, NY, 12180
Yaron Danon
DOE Nuclear Data Needs and Capabilities for Applications (NDNCA) workshop, LBNL, May 27-29, 2015
2nacThe Gaerttner LINAC Center
RPI Faculty
Prof. Yaron Danon - LINAC Director
Prof. Li Liu
KAPL
Dr. Greg Leinweber
Prof. (Emeritus) Robert C. Block
Dr. Devin Barry
Dr. Michael Rapp
Dr. Tim Donovan
Mr. Brian Epping
Dr. John Burke
Technical Staff
Dr. Ezekiel Blain
Peter Brand
Michael Bretti
Matt Gray
Azeddine Kerdoun
Graduate Students
Adam Daskalakis
Brian McDermott
Adam Weltz
Nicholas Thompson
Kemal Ramic
Carl Wendorff
Amanda Youmans
Jesse Brown
RPI Nuclear Data Group
BOLD= researcher or graduate students supported by NCSP
This work was supported by the following DOE grants: KAPL/BMPC/NCSP POs 103971, 7013680, DE-NAOOO1814,DE-FG03-03NA00079, DE-FG52-06NA26202, DE-FG52-09NA29453.
3nacThe Gaerttner LINAC Center
Overview• The Gaerttner LINAC Center at RPI
• Capability Matrix
• Measurement Capabilities and Examples– Thermal Region: Transmission, Capture, Fission, (S(a,b) at SNS)
– Resolved Resonance Region: Transmission, Capture, Fission
– Unresolved Resonance Region: Transmission, Capture
– Fast Neutrons: Transmission, Scattering, Prompt Fission Neutron Spectrum
– Lead Slowing Down Spectrometer: Fission, (n, alpha), (n, p), Capture
– Prompt fission neutrons: The gamma tagging method
The target room
4nacThe Gaerttner LINAC Center
Why Should We Care About Nuclear Data?
Nuclear Data(Uncertainty)
Geometry Data
ComputationalMethods (Physics)
(Uncertainty??)
ResultsAccuracy??
Reactor Physics Calculations
• Effective neutron Multiplication factor• Neutron flux• Burnup• Kineticswww.llnl.gov
The Shippingport Reactor (Critical in 1957)http://www.pabook.libraries.psu.edu/palitmap/Shippingport.html
5nacThe Gaerttner LINAC Center
Nuclear Data Lifecycle (Danon’s view)
Application Driven
Evaluation ValidationDifferential
Experiments
Integral Experiments
Evaluated Data File
ENDF/B-VII.1
Critical BenchmarksAt RPI
Publication(s)
User Needs
Publication(s) Publication(s)
Publication(s)
$$ O
ther
Users
Appropriate Exp only
Applications
6nacThe Gaerttner LINAC Center
Where is the RPI LINAC ?• It is on the highest point in Troy, NY
LINACFlight
Stations
NESOffices
RPI Campus
7nacThe Gaerttner LINAC Center
RPI LINAC History• The RPI LINAC started operation in December 1961.• Working “continuously” since.
Graduated over 170 students who utilized the LINAC as part of their PhD
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
8nacThe Gaerttner LINAC Center
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
SHO P AREA
BUILDING
HO T
LABORATO RY
DARKROO M
CO NTRO LROO M N EEP LAB
STO RAGE
ROO M
ROO M
TARGET
ACCELERATOR
ROO M
ROO MMO DULATOR
N ICE
LAB
ROO M
TARGET
ACCELERATOR
ROO M
N
GAERTTNER LINAC LABORATORY
INSTITUTERENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTERENSSELAER POLYTECHNIC
HO T
ROO M
TARGET
ACCELERATOR
ROO M
N ICE
LAB
ROO M
TARGET
ACCELERATOR
ROO M
25-METER
STATION
100-M ETER 250-M ETER STATION
N
GAERTTNER LINAC LABORATORY
INSTITUTERENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTERENSSELAER POLYTECHNIC
N
GAERTTNER LINAC LABORATORY
INSTITUTERENSSELAER POLYTECHNIC
30 PO RT
EN ERGY
AN ALYZIN G
MA GNET
He FLIGHT PATH
15-METER
D ETEC TORTRAN SMISSION
CAPTUREDETECTOR
DETECTOR
TRANS MIS SIO N
AUXILLARYEQ UIPMENTROO M
Bent/T il t
Focus
SPECTROMETER
LEAD SLOWING DOWN
EAST
45-METER STATIONSTATION
WEST
Neutron Production Target
Large Target Room
Detection Stations at:15m to 250m
Lead Slowing Down Spectrometer
Electron LINAC
9nacThe Gaerttner LINAC Center
LINAC Specifications 2015Three Sections
(Low Energy Port)Nine Sections
(High Energy Port)
Electron Energy
5 to 25 MeV 25 to over 60 MeV
Pulse Width 6 to 5000 ns 6 to 5000 ns
Peak Current
3A (short pulse: 6 to 50 ns)400 mA (long pulse: 50 to 5000 ns)
3A (short pulse: 6 to 50 ns)400 mA (long pulse: 50 to 5000 ns)
Average Power
10 kw@ 17 MeV, 5000 ns >10 kw@ 60 MeV, 5000 ns
Peak Dose Rate
>1011 Rads/sec (in Silicon) n/a
NeutronProduction
n/a ~4 X 1013 neutrons/sec
PulseRepetition
Rate
Single pulse to 500 pps (short pulse)Single pulse to 300 pps (long pulse)
Single pulse to 500 pps (short pulse)Single pulse to 300 pps (long pulse)
10nacThe Gaerttner LINAC Center
Capability Matrix and Development
10-3 10-2 10-1 100 101 102 103 104 105 106 107
PAC
BBT/PAC C6D
6 Capture Detector
ETT
LSDS fission / fragment dist.PFNS
Fast/LiGlass ArrayBT
BBT/PACMultiplicity Detector
Fission
PAC 100m LiGlass Detector
Under Development
BBT
ETT
BT
BT
BBT
ETT
Scattering
Capture
Neutron Energy [eV]
Transmission
15m LiGlass Detector
25m/30m LiGlass Detector
250m EJ301
Multiplicity Detector
Muliplicity Detector
EJ301 Array
RPI LINAC - Nuclear Data Measurement Capabilities 2015
BBT/PAC/BBT
ETT
TargetsETT- Enhanced Thermal TragetBBT - Bare Bounce TargetBT- Bare Target on AxisPAC - PacMan Target
Multiplicity Detector
Multiplicity Detector
Multiplicity Detector
New
New
11nacThe Gaerttner LINAC Center
Neutron Production TargetsEnhanced Thermal Target (ETT)Bare Bounce Target (BBT)
PACMAN target
12nacThe Gaerttner LINAC Center
Detectors
Transmission
Capture/multiplicity
ScatteringPFNS
25m
30m
45m
13nacThe Gaerttner LINAC Center
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 (0.4-20MeV)• Scattering (30 m flight path)• Transmission (100m and 250m flight path)• Prompt Fission Neutron Spectra
– High accuracy total cross section measurements using 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– S(a,b) measurements (at SNS in ORNL)
14nacThe Gaerttner LINAC Center
Resonance Region
15nacThe Gaerttner LINAC Center
Transmission Experiment
Li-Glass Neutron DetectorNeutron Beam
Neutron Beam
Sample
)exp(Out Sample
In SampletN
C
CT
N – Number density [atoms/barn]t – Total cross section
Li-Glass Neutron Detector
Two Experiments:1. Sample Out
2. Sample In
16nacThe Gaerttner LINAC Center
Capture Experiments
Gamma RaysNeutron Beam
Multiplicity Detector
t
tNY
)exp(1
The capture Yield:
Sample
YCounts – neutron flux – detection efficiency
17nacThe Gaerttner LINAC Center
Resonance Cross Section Measurements Data Analysis
Data Reduction
Experiment
Data Analysis
CollectTransmission Data
ThermalData & Background
EpithermalData & background
Reduce toTransmission
2-5 samples
Fit DataSAMMY code
CollectCapture Data
ThermalData, Background &
Flux
EpithermalData, background &
Flux
Reduce toCapture Yield
2-5 samples
Resonaceparameters
Various Parameters
• US Cross Section Evaluation Working Group (CSEWG)
• Users - Evaluated Data Files ENDF/B-VII.1
18nacThe Gaerttner LINAC Center
Elemental Molybdenum
0 50 100 150 2000.0
0.2
0.4
0.6
0.8
1.0
0 50 100 150 200
0.0
0.2
0.4
0.6
0.8
1.0
0 50 100 150 200
1E-3
0.01
0.1
0.5
Tra
nsm
issi
on
200-mil Mo SAMMY calc 100-mil Mo SAMMY calc 50-mil Mo SAMMY calc 25-mil Mo SAMMY calc 10-mil Mo SAMMY calc 5-mil SAMMY calc ENDF/B-VI.8 200-mil ENDF/B-VII 200-mil
Energy, eV
Tra
nsm
issi
on
250-mil Mo SAMMY calc ENDF/B-VII.0 250-mil ENDF/B-VI.8 250-mil 100-mil Mo SAMMY calc
Cap
ture
Yie
ld
20-mil Mo SAMMY calc ENDF/B-VII.0 20-mil ENDF/B-VI.8 20-mil 10-mil Mo SAMMY calc 5-mil Mo SAMMY calc 2-mil Mo SAMMY calc
19nacThe Gaerttner LINAC Center
Elemental Molybdenum 120 eV - 145 eV
120 125 130 135 140 145
0.00
0.05
0.10
0.15
0.200.00
0.20
0.40
0.60
0.80
1.00
Cap
ture
Yie
ld
Energy [eV]
20-mil Mo 10-mil Mo 5-mil Mo 2-mil Mo SAMMY calc ENDF/B-VII.0 20-mil
Tra
nsm
issi
on 200-mil Mo 100-mil Mo 50-mil Mo 25-mil Mo 10-mil Mo 5-mil SAMMY Fit ENDF/B-VII 200-mil
20nacThe Gaerttner LINAC Center
Gd Thermal Region - Separated Isotopes
0.002 0.01 0.1 1-0.10.00.10.20.30.40.50.60.70.80.91.01.11.2
0.002 0.01 0.1 1-0.10.00.10.20.30.40.50.60.70.80.91.01.11.2
Energy [eV]
Tra
nsm
issi
on
LX-2 155Gd
LX-4b 155Gd
LX-5 157Gd
LX-7 157Gd 0.025-mm metal 0.051-mm metal SAMMY fit
Cap
ture
Yie
ld
LX-4 155Gd
LX-9 155Gd
LX-10 157Gd
LX-11 157Gd SAMMY fit
0.02 0.03 0.04 0.05-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.02 0.03 0.04 0.05-0.10.00.10.20.30.40.50.60.70.80.91.01.11.2
Cap
ture
Yie
ld
LX-9 155Gd LX-10 157Gd RPI ENDF
Energy [eV]
Tra
nsm
issi
on
LX-4b 155Gd LX-7 157Gd 0.025-mm metal RPI ENDF
21nacThe Gaerttner LINAC Center
235U Capture & Fission Yield Data - Epithermal Measurement
• Challenges:• Normalization• False capture due to neutron scattering
Normalize experimental fission yield to resonance
Use two equations for predominantly capture and fission resonances
Solve the two equations for k2 and k3
► Need 2 resonances with known parameters ◄
fENDFf YkY 1
86.0
fENDF YkkYkY 222 132
63.0f
fENDF 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 Capture
Normalization
Yie
ldf
Neutron Energy [eV]
RPI Fission Sammy Fission
600 700 800 900 10000.00
0.01
0.02
0.030.00
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
63.0f
22nacThe Gaerttner LINAC Center
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.
23nacThe Gaerttner LINAC Center
High Resolution Transmission Detector• Modular Li-Glass detector at 100m flight path
– Extends our capabilities to the unresolved resonance region
– Measurement of 95,96,98,100Mo completed.
Neutron Beam
6Li-Glass
100m flight station
LINAC Target Room
45m flight station
24nacThe Gaerttner LINAC Center
Mo Isotopes in the Resonance Region100m Flight Path
• Resonance parameters analysis in progress
• Data provide information to extend the resolved resonance region of several isotopes
0.0
0.5
1.0
0.0
0.5
1.0
0.0
0.5
1.0
1000 10000 20000 30000 40000 500000.0
0.5
1.0
Mo-98 Exp Mo-98 ENDF-7.0
Mo-95 Exp Mo-95 ENDF-7.0
Tra
nsm
issi
on
Mo-96 Exp Mo-96 ENDF-7.0
Mo-100 Exp Mo-100 ENDF-7.0
Energy [eV]
25nacThe Gaerttner LINAC Center
Mid-Energy Capture DetectorSystem Overview
• 4 C6D6 detector modules manufactured by EljenTechnology
• 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
26nacThe Gaerttner LINAC Center
natFe Capture measurement• natFe was used as a test to compare with evaluations and other measurements
– The RPI data (45m flight path) has good energy resolution compared to the Spencer ORELA data (40m flight path)
– The RPI data provide information above 700 keV (next slide)
10 20 30 40 50 60 70 80 90 1000.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
Spencer: N=0.0105 atm/bRPI: N=0.17133 atm/b
Cap
ture
Yie
ld
Energy [keV]
RPI (150 keV Cut) RPI/Sammy (ENDF/B-VII.1) Spencer/Sammy (ENDF/B-VII.1) Spencer 1994 (ORELA)
300 320 340 360 380 400 420 44010-6
10-5
10-4
10-3
10-2
10-1
Cap
ture
Yie
ld
Energy [keV]
RPI (150 keV gamma cut) RPI/Sammy (ENDF/B-VII.1) Spencer/Sammy (ENDF/B-VII.1) Spencer 1994 (ORELA)
27nacThe Gaerttner LINAC Center
natFe Capture Cross Section above 847 keV
• New capture data obtained above 847 keV and 1409 keV inelastic states in 56Fe and 54Fe
• Capture signal separated from inelastic scattering signal by post-processing digitized waveforms with different energy deposition cutoffs
• Good agreement with other experiments
• The data is lower than the evaluations above 1400 MeV 750 1000 1250 1500 1750 2000600
10-4
10-3
10-2
10-1
100
101
54Fe 1st inelastic state
RPI (150 keV Cut) RPI (900 keV Cut) RPI (1410 keV Cut) Spencer 1994 Malyshev 1964 Diven 1960 ENDF/B-VII.1 JEFF3.1
Cro
ss S
ectio
n [b
]
Energy [keV]
56Fe 1st inelastic state
28nacThe Gaerttner LINAC Center
Unresolved Resonance Region
29nacThe Gaerttner LINAC Center
New Method – Fe Filtered Beam CaptureResults for 181Ta
• Measurements performed on 181Ta using Fe-filtered beam technique
• 30cm thick Fe filter removes all beam-related gamma and neutron background
• Provides a quasi-monoenergeticneutron source corresponding to deep minima in the Fe cross section
103 104 105 106 1070.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Tra
nsm
issi
on
Energy [eV]
30cm Nat. Fe
30nacThe Gaerttner LINAC Center
Mid-Energy Capture DetectorExperimental Results-181Ta
• Count rates for Ta and B4C samples were summed under each filter transmission peak.
• Pb scattering sample used to confirm negligible neutron background
5.0 7.5 10.0 12.5 15.00.0
5.0x104
1.0x105
1.5x105
2.0x105
Wei
ghte
d C
ount
s
TOF [s]
6mm Ta 13mm B
4C
10mm Pb
6.8 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.40.0
5.0x104
1.0x105
1.5x105
2.0x105
Wei
ghte
d C
ount
s
TOF [s]
31nacThe Gaerttner LINAC Center
181Ta Iron Filtered Beam Capture Measurement:Cross Section
• As expected thick sample=problems– Self shielding correction is high
– Multiple scattering correction is high
– Need to work on better understanding of the weighting function and it validity
• Thin sample support the JEFF-3.1/3.2 evaluation
• Possible contamination from inelastic scattering apparent in ENDF/B-VII.1
10 100 1000 50000.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
181Ta (n,)
Cro
ss S
ectio
n [b
]
Energy [keV]
ENDF-B/VII.1 JEFF-3.1 JENDL-4.0 Block (1972) Lindner (1976) Macklin (1984) Yamamuro (1980) Miskel (1962) Reffo (1982) Brzosko (1969) RPI 2014 (2mm sample) RPI 2014 (6mm sample)
32nacThe Gaerttner LINAC Center
Fast Region
33nacThe Gaerttner LINAC Center
Water Cooled Ta
Target
SampleEJ-301 Liquid Scintillator
Modular Detector
250 m
CollimationCollimationCollimation
U/Pb Filter
High Energy Transmission Experimental Setup
Graphite Samples
33
137 5
Nominal thickness in cm
34nacThe Gaerttner LINAC Center
Beryllium Transmission
0.5 1 100.0
0.2
0.4
0.6
0.8
1.0
Be 2 cm Be 4 cm Be 8 cm ENDF/B-VII.0 JENDL3.3
Tra
nsm
issi
on
Energy [eV]
15
234
8
Beryllium samplesSample thickness is given in cm
Reconfigured the detector with two units to reduce background
35nacThe Gaerttner LINAC Center
Beryllium Total Cross Section (Low Energy)
0.4 0.5 0.6 0.7 0.8 0.9 1.03
4
5
6
7
8
2 cm sample 4 cm sample Filtered Beam experiment ENDF/B-VI.8 ENDF/B-VII.0 JENDEL 3.2
Cro
ss S
ectio
n [b
arn]
Energy [MeV]
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 MeV”, Nuclear Science and Engineering, Vol. 172, No. 3. Pages 268-277, November 2012 (2012).
36nacThe Gaerttner LINAC Center
Ti Total Cross Section Measurements0.5 – 20 MeV
• 250m flight path measurement shows structure that was not resolved in prior measurements
• JEFF 3.1.2 shows an energy shift
• ENDF/B-VII.1 lower resolution than JEFF 3.1.2 and ENDF/B-VII.0
0.5 1 10 200
1
2
3
4
5
6
7
8
9
t [b
]
Energy [MeV]
8cm Ti data 12cm Ti data ENDF/B-VII.1
0.60 0.65 0.70 0.75 0.800
2
4
6
8
10
t [b
]
Energy [MeV]
250m RPI data 100m RPI data Schwartz et. al. (1974) ENDF/B-VII.0 ENDF/B-VII.1 JEFF 3.1.2
12 cm8 cm
37nacThe Gaerttner LINAC Center
Zr Total Cross Section Measurements (0.5-20 MeV)
• 100m flight path• 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
t [b
arn]
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
t [
barn
]Energy [MeV]
RPI Experiment Arpil - May 2008
ENDF/B-6.8
ENDF/B-7.0
JEFF 3.1
JENDL 3.3
38nacThe Gaerttner LINAC Center
Fast Neutron Scattering
Quasi-differential neutron scattering and angular distributions.
39nacThe Gaerttner LINAC Center
TOF Scattering Measurement• Measure TOF: t = t1 + t2; where t1 » t2
• All scattering events: E2 < E1
• For elastic scattering with A » 1: E1 ~ E2
• Assuming L = L1 + L2 than total TOF, t, can be used to calculate the incident neutron energy, E1(t)
L1, t1, E1
L2, t2, E2L1 ~ 30m
L2 ~ 0.5m
1
1
1)(
2
21
tc
LcmtE n
40nacThe Gaerttner LINAC Center
238U Scattering Measurement - JEFF 3.2
Library FOM
JEFF-3.1 3.0
JEFF-3.2 2.8
Library FOM
JEFF-3.1 20.4
JEFF-3.2 7.9
500 800 1200 1600 2000 2400 2800 31280
1000
2000
3000
4000
50000.10.51251020
153 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
Uranium Data JEFF-3.2 JEFF-3.1
500 800 1200 1600 2000 2400 2800 31280
1000
2000
3000
4000
5000
6000
7000
80000.10.51251020
60 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
Uranium Data JEFF-3.2 JEFF-3.1
Significant improvement in JEFF3.2
41nacThe Gaerttner LINAC Center
Fe Scattering Measurement - Setup
The neutron beam size is smaller than the sample.
EJ-301 Liquid Scintillator Neutron Detectors
• Fe Sample• Dimensions 77.0 x
152.6 x 32.2 mm
Evacuated Flight Tube
42nacThe Gaerttner LINAC Center
natFe Scattering - 61°
Library FOM
ENDF/B-VII.1 9.5
JEFF-3.2 9.5
JENDL-4.0 8.4
Reference FOM
Graphite 1.3
1000 1500 2000 2500 30005000
500
1000
1500
2000
2500
30000.511.5251020
61 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
1750 2000 2250 2500 2750 300015000
500
1000
1500
2000
2500
30000.511.52
61 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
800 1200 1600 2000 2400 2800500 31280
500
1000
1500
2000
2500
30000.511.5251020
Energy [MeV]
Cou
nts
Time of Flight [ns]
Graphite Data MCNP Results
61 deg
43nacThe Gaerttner LINAC Center
natFe Scattering - 153°
Library FOM
ENDF/B-VII.1 25.9
JEFF-3.2 39.8
JENDL-4.0 23.4
Reference FOM
Graphite 4.9
1800 2100 2400 2700 30001550 31280
1000
2000
3000
4000
5000
6000
7000
8000
9000
100000.512
153 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
800 1200 1600 2000 2400 2800500 31280
2000
4000
6000
8000
100000.51251020
Energy [MeV]
Cou
nts
Time of Flight [ns]
Graphite Data MCNP Results
153 deg
1000 1500 2000 2500 30005000
1000
2000
3000
4000
5000
6000
7000
8000
9000
100000.51251020
153 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
44nacThe Gaerttner LINAC Center
Inelastic to Elastic Ratio
• Multiple scattering effects included in MCNP simulations• Statistical and systematic uncertainties included in analysis
1.4 1.6 1.8 2.00.0
0.2
0.4
0.6
0.8
1.0 Inelastic to Elastic Ratio JEFF-3.1
Inelastic to Elastic Ratio ENDF/B-VII.1
Inelastic to Elastic Ratio JENDL-4.0Nat
Fe Ratio
Inel
astic
-to-
Ela
stic
Rat
ioIncident Neutron Energy [MeV]
Detector 3 at 153o
1.4 1.6 1.8 2.00.0
0.2
0.4
0.6
0.8
1.0
1.2I/E Ratio JEFF-3.2I/E Ratio ENDF/B-VII.1I/E Ratio JENDL-4.0NatFe Ratio
I/E
Rat
io
Incident Neutron Energy [MeV]
Detector 6 at 130o
1600 1650 1700 1750 1800 1850 190015500
1000
2000
3000
4000
5000
6000
7000
8000
9000
1000011.41.51.61.71.81.92
153 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
1600 1650 1700 1750 1800 1850 19001550 19250
500
1000
1500
2000
2500
3000
350011.41.51.61.71.81.92
130 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
NatFe Data ENDF/B-VII.1 JEFF-3.2 JENDL-4.0
45nacThe Gaerttner LINAC Center
Comparing Experiments and SimulationElastic scattering
• Experimental elastic scattering was inferred from 0.5 to 2.0 MeV– The experimental data is reasonably represented by a simulation with ENDF/B-VII.1
• Collaborating with ORNL to improve new 56Fe evaluation
1500 1800 2100 24000
500
1000
1500
2000
2500
3000
35000.10.50.851251020
130 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
Total Scattering Data ENDF/B-VII.1 Total
Elastic Scattering Data ENDF/B-VII.1 Elastic
1500 1800 2100 24000
1000
2000
3000
4000
50000.10.50.851251020
153 deg
Energy [MeV]
Cou
nts
Time of Flight [ns]
Total Scattering Data ENDF/B-VII.1 Total Elastic Scattering Data ENDF/B-VII.1 Elastic
46nacThe Gaerttner LINAC Center
Resonance Scattering
Example of an experiment for testing the physics models of Monte Carlo codes
47nacThe Gaerttner LINAC Center
Resonance Scattering Experiment• Motivation – Provide a benchmark to the model developed by Dagan et al.
– Poor approximation of the scattering kernel when the cross section is energy dependent.
• Use the Time-Of-Flight (TOF) method– The TOF will correspond to the scattered neutron energy– Scattering in forward and backward scattering angles can be measured
Electron Beam
NeutronProducing Target
238U sample
Good CollimationNeutron Detector
~25.5 m
n
q
48nacThe Gaerttner LINAC Center
Resonance Scattering- Experimental Setup
SampleBlank
Ta Targete- beam line
Moderator
49nacThe Gaerttner LINAC Center
Resonance Scattering-Measured Data• Thick Sample time-of flight spectrum forwards scattering
100 200 300 400 500 600 700 800 900 1000
200
400
600
800
1000
1200
1400
1600
1800
2000
280 290 300 310 320 330 3400
200
400
600
800
1000
6.671 eV
20.972 eV
Cou
nts
TOF [s]
238U Thick sample Background (no sample)
36.68 eV
TOF [s]
Cou
nts
50nacThe Gaerttner LINAC Center
34 35 36 37 38 39 400
100
200
300
400
500
RPI Experiment MCNP (Modified) MCNP+S(a,b)
Cou
nts
Scattered Neutron Energy [eV]
E0=36.68 eV
Sample thickness=1/16"
34 35 36 37 38 39 400
100
200
300
400
RPI Experiment MCNP (Modified) MCNP+S (a,b)
Cou
nts
Scattered Neutron Energy [eV]
E0=36.68 eV
Sample thickness ~1/16"
34 35 36 37 38 39 400
100
200
300
400
500
RPI Experiment MCNP (unchanged) MCNP (modified) MCNP+S(a,b)
Cou
nts
Scattered Neutron Energy [eV]
E0=36.68 eV
Sample thickness=1/8"
Resonance Scattering - Results for238U Scattering
Back Forward
ThickSample
ThinSample
Back Forward
34 35 36 37 38 39 400
200
400
600
800
1000
Sample thickness=1/8"
RPI Experiment MCNP (Unchanged) MCNP (Modified) MCNP+S(a,b) Geant 4
Cou
nts
Scattered Neutron Energy [eV]
E0=36.68 eV
In 2009 all MC codes had this problem Today some still do
51nacThe Gaerttner LINAC Center
Lead Slowing Down Spectrometer
52nacThe Gaerttner LINAC Center
VacuumTi Window
ElectronBeam
He Filled Drift Section
Neutron Source(He cooled Ta Target)
LEAD
Crossed I beam + Li2Co3
180 cm
180
cm
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
53nacThe Gaerttner LINAC Center
Fission Fragment Kinematics
• Objectives– Simultaneous measurement of the fission cross section
and fission fragment mass and energy distributions of small samples (~nanograms).
• Method– Use the RPI lead slowing down spectrometer and a
double gridded fission chamber.
– Samples are deposited on very thin backing (~250 nm)
54nacThe Gaerttner LINAC Center
SETUP
VacuumTi Window
ElectronBeam
He Filled Drift Section
Neutron Source(He cooled Ta Target)
LEAD
Crossed I beam + Li2Co3
180 cm
180
cm
Fission Chamber
Flux Monitor
Flux Monitor
Flux Monitor
Anode
Anode
Cathode
Sample
CH4 Inlet
Filter
FilterTeflon rods
q
e- e
- e- e
-
+ +
+ +
Grid
Grid
DGGV486
CFDV812
AmplifierN568B
FIFON401
FIFO
FIFO
FIFO
FIFO
FIFO
FIFO
CFD1
CFD2
CFD3
DGG1
ADCV785
TDCV775
ScalerV830
Start
Stop1
Stop2
DGG2
DGG3
Reset/Start
TRG
LINAC Pretrigger
10 MHzClock
IN1
ADC1
ADC6
ADC5
ADC4
Gate
ADC3
ADC2
Preamplifiers
VMEMM
Fission Chamber
Cathode
Anode-1
Anode-2
Grid-1
Grid-1
-3.0 KV
-1.5KV
-1.5 KV
Double Gridded Fission Chamber
Multiparameter DAQ
Collaboration with LANL• Fission cross sections.• (n,a), (n,p) measurements on small samples.
55nacThe Gaerttner LINAC Center
Results – Fission Fragment Mass distribution En<0.1 eV235U 239Pu
80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09252Cf Preneutron Emission Mass
Yie
ld
Mass [amu]
Hambsch Current Data
60 80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09252Cf Postneutron Emission Masses
Yie
ld
Mass [amu]
Current Data JEFF3.1
252Cf
60 80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
235U Preneutron Emission Fission Fragment Mass
Yie
ld
Mass [amu]
Hambsch Data Current Data
60 80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
Yie
ld
Mass [amu]
Current Data JEFF3.1
235U Post Neutron Emission Masses
60 80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09239Pu Post Neutron Emission Masses
Yie
ldMass [amu]
ENDF/B-VII.0 Current Data
60 80 100 120 140 160 1800.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09239Pu Preneutron Emission Masses
Yie
ld
Mass [amu]
Current Data Hambsch Data
56nacThe Gaerttner LINAC Center
Results – Fission Fragment Energy Distribution En<0.1 eV
40 60 80 100 120 40 60 80 100 12040 60 80 100 1200.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
Yie
ld
Energy [MeV]
252Cf Energy
235U Energy
239Pu Energy Hambsh Data
57nacThe Gaerttner LINAC Center
Fission symmetry in resonance clusters
10-1 100 101 102 103 104100
101
102
103
Current Data ENDF/B-VII.0
thermal 1<0.1 eV
res9res8
res7
res6
res5
res4
res3
res2
high res
f [b
arn]
Energy [eV]
0 1 2 3 4 5 6 7 8 9 10 11-0.5
0.0
0.5
1.0
1.5
2.0
2.5Symetric Fission in Resonances Relative to Thermal
Sym
reso
nanc
e/Sym
ther
mal
Resonance Number
Current Data Hambsch Data Faler Data
58nacThe Gaerttner LINAC Center
239Pu - Results
E<0.1 eV (region 1)
80 100 120 140 160150
160
170
180
190
200
210
Mass [amu]
TK
E [M
eV]
0.00
0.02
0.04
0.06
0.00
0.02
0.04
0.06
0.00
0.02
0.04
0.06
60 80 100 120 140 1600.00
0.02
0.04
0.06
60 80 100 120 140 160
0.00
0.02
0.04
0.06
Region 2
Region 3
Region 4
Yie
ld (
1/am
u)
Region 5
Region 6
Yie
ld (
1/am
u)
Region 7
Mass (amu)
Yie
ld (
1/am
u)
Mass (amu)
Region 9
Region 10high energy
Yie
ld (
1/am
u)
Yie
ld (
1/am
u)
Region 1 Thermal
Region 8
10-1 100 101 102 103100
101
102
103
104
1
1098
756
43
f [
barn
]
Neutron Energy [eV]
2
59nacThe Gaerttner LINAC Center
(n,a) cross section measurementsCompensated PIPS Detector
PIPSDet.
PIPSDet.
BNC Model 555
Ch A
Ch B
Ch D
Ch C
Ext
5M
5M
T0 fromControlRoom
45ns Cramtemodel 110
Pre-Amplifier
100ns Cremat model200 Shaper Amplifier
PhillipsScientific
Model #460Inverting
Transformer(Modifier)
PhillipsScientific
Model #460Inverting
Transformer
4.7nF 4.7nF
4.7nF4.7nF
4.7nF 4.7nF
4.7nF
4.7nF
Tabor Model8024 Function
Generator
Out
Trig In
NHQ 204MHVPS (20V)
Acqiris DC440DigitizerC
h 1
Ch 2
I/O A
I/O B
•Gamma discrimination by recording the gamma spectra on two face to face detectors
•Digital DAQ collects a bipolar signal
•Correct for background by subtracting the bare detector signal from the sample detector on an event by event basis
Sample
Sample Position
60nacThe Gaerttner LINAC Center
(n,a) and (n,p) measurement results• Measurement of (n,a) cross section of 147,149Sm• Demonstrate the ability to measure micro barn cross sections with the
LSDS
J.T. Thompson, T. Kelley, E. Blain, R.C. Haight, J.M. O'Donnell, Y. Danon, “Measurement of (n,α) reactions on 147Sm and 149Sm using a lead slowing-down spectrometer”, Nuc. Inst. and Meth. A, Vol. 673, pp. 16-21, May (2012)
61nacThe Gaerttner LINAC Center
Capture measurements with the LSDS
• Use a Lead Slowing Down Spectrometer to measure the capture rate of samples of small mass or small cross section– Detect from capture
• Criteria for a detector– Low n-capture cross section– Low n-scattering cross section– High γ detection efficiency– Small detector (reduce background)– Fast recovery from gamma flash
Sample
n from Pb
from Pb
Scattered neutron
62nacThe Gaerttner LINAC Center
Ta capture rate• 2mm YAP Detector, 10 Mil Ta Sample
– The measurement extends to ~50 keV– Good agreement with the simulations– Data collection time was about 20 minutes
100 101 102 103 10410-1 5x104
103
104
105
106
102
107
Cou
nt R
ate
[Cou
nts/
seco
nd]
Energy [eV]
Measurement ,10 Mil Ta, 1 YAP Detector MCNP ENDF/B-II.1 10 Mil Ta, 1 YAP Detector
63nacThe Gaerttner LINAC Center
100 101 102 103102
103
104
105
106
107
Rat
e [c
ps]
Time [s]
Experiment, 2mm YAP 3mm Nickel Sample Background Sample - Background
Ni Capture rate• 2mm YAP detector, 3mm nickel sample
– Low capture cross section Low S/B– Reasonable agreement with ENDF/B-VII.1 – Additional peaks observed near 200-300 eV possible impurities in sample
10-1 100 101 102 103 104 5x104102
103
104
105
106
Rat
e [c
ps]
Energy [eV]
3mm Nickel Sample Measurement Simulation, ENDF/B-VII.0
64nacThe Gaerttner LINAC Center
Prompt Fission Neutron Spectra
65nacThe Gaerttner LINAC Center
Experimental Setup
SamplePosition
EJ-301Detectors
GammaDetectors
EJ-204Detector *
E1
L1=30 m
E2
L2=0.5m
4 Gamma Detectors(top view)
Neutron Detectors
Sample
• Neutron Detectors– EJ-204 Plastic Scintillator
• 0.5” x 5”
• 47 cm away from center of sample– 2 EJ-301 Liquid Scintillators
• 3” x 5”
• 50 cm away from center of sample
• Gamma Detectors– 4 BaF2 detectors on loan from ORNL– Hexagonal detectors 2” x 5”
– 10 cm from center of sample– ¼” lead shield between detectors
• Reducing scattering between detectors
energyneutronfission E
energyneutron incident E
distanceflightpath
3.72
2
1
2,1
2/1
2
2
1
1
Lm
eVsk
E
kL
E
kLToF
66nacThe Gaerttner LINAC Center
252Cf Prompt Fission Neutron Spectrum• Good agreement seen between the RPI datasets in the overlap region
from 0.7 MeV to 2 MeV
• Combined datasets provide measurement from 0.05 Mev to 7 MeV
67nacThe Gaerttner LINAC Center
238U Prompt Fission Neutron Spectrum
• Spectrum is integrated over two incident energy regions, first chance fission and second chance fission
• Data shows good agreement with current evaluations• Increase near 1 MeV agrees with new data by Sardet et. al.• Both spectra normalized at 2.25 MeV
68nacThe Gaerttner LINAC Center
LINAC 2020 Refurbishment and Upgrade Plan
• Project aims at refurbishment and upgrade of the accelerator– Increase neutron production as short pulses
• Increase the electron beam energy
• Modernize the electron beam control system
– Provide longevity• Replace all major components and acquire spares
• Funded by DOE-NR and NCSP through BMPC/KAPL