1 nacThe Gaerttner LINAC Center
Experimental Nuclear Data Program at the Gaerttner LINAC Center at RPI
Rensselaer Polytechnic Institute, Troy, NY, 12180 Y. Danon, E. Liu, A. Daskalakis, B. McDermott, C. Wendorff, K. Ramic
NCSP Meeting, LANL, March 26-27,2013
2 nacThe 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 Peter Brand Matt Gray Martin Strock Azeddine Kerdoun Graduate Students Rian Bahran (PhD) – now at LANL Ezekiel Blain Dave Williams Adam Daskalakis Brian McDermott
Adam Weltz Nicholas Thompson Kemal Ramic Carl Wendorff Undergraduate Students Amanda Youmans
RPI Nuclear Data Group
3 nacThe Gaerttner LINAC Center
Overview • ND-1- Resonance Region Nuclear Data Measurement
– Development of a new mid energy capture detector • 45m flight path, energy range from 1 keV to 500 keV • Performed measurements of Fe and 92/94Mo
– Transmission measurement of 186W at 35m • In support of ORNL ND task
– Neutron scattering measurements for 56Fe • 30m flight path, 0.5 MeV to 20 MeV • Obtained the ratio of inelastic to 1st state to elastic scattering.
• ND-2 Thermal Neutron Scattering Measurements – Performed analysis of previously measured samples of water and medium
density polyethylene. – Measured neutron scattering from samples of quartz (SiO2) and High Density
Polyethylene (HDPE) at several temperatures. • ND-3 LINAC 2020 Refurbishment and Upgrade Plan
– Project started, klystron order expected in FY-14
4 nacThe Gaerttner LINAC Center
Capability Development • Develop Mid energy (1 - 500 keV) capture detector
10-3 10-2 10-1 100 101 102 103 104 105 106 107
ETTLSDS fission σ / fragment dist. 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
p
BBT/PAC/BBT
ETT
TargetsETT- Enhanced Thermal TragetBBT - Bare Bounce TargetBT- Bare Target on AxisPAC - PacMan Target
Multiplicity Detector
Multiplicity Detector
Multiplicity Detector
5 nacThe Gaerttner LINAC Center
New Flight Station and Capture Detector • Flight Station construction
completed in FY 12 • FY 13
– Installed capture detector array – Installed evacuated flight tubes – Installed sample changer – Performed a test run with Fe
• FY 14 – Resolving issues with two
detectors (sent back to Eljen) – Performed a scoping
measurement of Fe and 92/94Mo
6 nacThe Gaerttner LINAC Center
Mid-Energy Capture Detector
• Two detector modules exhibited poor energy resolution and pulse shape
• Modules were returned to vendor for repair and fitting with new PMTs
• Expected return date: April, 1, 2014
• Scoping experiment performed with 2 remaining detectors MCA spectra of 4 detector modules with
detectors 1 and 3 showing degraded performance
0 80 160 240 320 4000
10000
20000
30000
40000
50000
22Na - Analog
Cou
nts
Channel
D1: 2200V D2: 1840V D3: 2000V D4: 1647V
7 nacThe Gaerttner LINAC Center
Mid-Energy Capture Detector Sample Changer
• Ceiling-mounted sample changer • 84” Velmex BiSlide linear translation
module with stepper motor • Linear magnetic encoder for micron-
precision sample position verification • Customizable with up to 5 samples of
varying shapes and sizes • Lightweight aluminum construction • Computer controllable through
LabView, with custom control software under development
• Flight path was 45m
Sample Changer
Samples
Detectors
8 nacThe Gaerttner LINAC Center
Mid-Energy Capture Detector - DAQ
• Updated DAQ software for 10-bit, 1.25GHz SIS3305 digitizer
• Expandable to 8 DAQ boards with
8 channels each, for a total of 64 possible detector channels
• Buffered data transfer with real-time data streaming option under development
• Data collection paused during buffer transfer, <2% down time
• On-line plotting feature available using CERN ROOT libraries Screenshots of DAQ software in operation
9 nacThe Gaerttner LINAC Center
Raw Data for Fe capture experiment • Used 2 C6D6 Detectors • Data was grouped to
16 ns bins • Neutron count rate is
increasing with energy.
• Graphite sample was used to assess the neutron sensitivity
– Graphite counts are art background level (open)
– Longer measurement is needed to assess the scattering-to-capture ratio
1000 10000 10000010
100
1000
10000
Cou
nts
Energy [eV]
Fe B4C Open Graphite
10 nacThe Gaerttner LINAC Center
Scoping experiment for capture on 92/94Mo • Mo capture is one of the tasks
for FY-14 • Enriched Mo samples were
prepared by Bettis Atomic Power Lab (75.63% 92Mo, 23.78% 94Mo)
• For this scoping analysis data was grouped to 8 ns bins
• Samples were also measured in transmission at 100m flight path.
– An energy shift was observed in both measurements which indicates a possible error in ENDF
• The sample yield is low, a thicker sample might be needed for higher energies where the yield is lower
2000 2500 3000 3500 4000 4500 50000.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Yiel
d
Energy [eV]
700 mil sample SAMMY - ENDF/B-VII.1
11 nacThe Gaerttner LINAC Center
Transmission of 186W • Experiment was designed to provide
data in the energy range from about 2-4 keV (Na fixed filter at Geel)
• Sample provided by ORNL – 3 discs, 0.01169 atoms/barn – 238U sample for determination of the
energy resolution
• Data was collected for 3.5 days. – 35 m flight path – Pulse width of 10 ns
• Co and Al fixed notches were used for background determination
Detector
Sample
12 nacThe Gaerttner LINAC Center
186W Transmission results • Transmission measured
covers the energy range from a 10 eV to 400 keV
• The region of interest is highlighted in green
• On this scale seems like goo agreement with JENDL 4.0
• ENDF/B-VII.1 seemed to have some issue with extra resonances.
100 1000 2000 3000 4000 50000.0
0.2
0.4
0.6
0.8
1.0
186 W
Tra
nmis
sion
Energy [eV]
Experiment SAMMY - JENDL 4.0
13 nacThe Gaerttner LINAC Center
186W Transmission results: 2.5 – 3.2 keV • Energy resolution was fitted to the 238U sample • 186W shows energy shift which are not visible in the 238U • Preliminary data was delivered to ORNL
2500 2600 2700 2800 2900 3000 3100 32000.0
0.2
0.4
0.6
0.8
1.0
186 W
Tra
nmis
sion
Energy [eV]
Experiment SAMMY - JENDL 4.0
2500 2600 2700 2800 2900 3000 3100 32000.0
0.2
0.4
0.6
0.8
1.0
186 W
Tra
nmis
sion
Energy [eV]
Experiment SAMMY - ENDF/B-VII.0
238U 186W
14 nacThe Gaerttner LINAC Center
56Fe Scattering Measurement - Setup
The neutron beam size is smaller than the sample.
EJ-301 Liquid Scintillator Neutron Detectors
• 56Fe Sample • 99.87% metallic 56Fe • Dimensions 77.0 x
152.6 x 32.2 mm
Evacuated Flight Tube
15 nacThe Gaerttner LINAC Center
56Fe Scattering Measurement – Results 153°
The energy resolution is sufficient to show some discrepancies in the resonance region (E<850 keV)
500 1000 1500 2000 2500 30000
500
1000
1500
2000
2500
3000
3500
40000.51251020
153 deg
Energy [MeV]
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
2500 2550 2600 2650 2700 2750 28000
500
1000
1500
2000
2500
3000
3500
4000
153 deg
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
16 nacThe Gaerttner LINAC Center
Fe-56 Scattering Measurement – Results 153° • Above the first inelastic state
(E>847 keV) there are some differences with the evaluations
• We are exploring the possibility to extract double differential cross section data from these experiments.
500 1000 1500 2000 2500 30000
500
1000
1500
2000
2500
3000
3500
40000.51251020
153 deg
Energy [MeV]
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
1800 1900 2000 2100 2200 23000
500
1000
1500
2000
2500
3000
3500
40001
153 deg
Energy [MeV]
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
17 nacThe Gaerttner LINAC Center
Elastic to Inelastic Scattering Ratio: Data • 56Fe scattering measured data for
En>1.3 MeV includes elastic and inelastic neutrons – We can measure scattered neutrons
when En>0.5 MeV • The energy deposition by inelastically
scattered neutrons is much lower than that of elastically scattered neutrons (by ~0.847 MeV depending on the scattering angle)
• The pulse height spectrum collected over a narrow neutron time of flight range corresponding to a certain incident neutron energy enables separation the two contributions.
0 100 200 300 400 5000
100
200
300
400
500
600
Coun
ts
Pulse Integral [channel #]
56Fe at 2 ± 0.05 MeV In-beam at 2 MeV (Normalized) In-beam at 1.15 MeV (Normalized) Linear Combination
18 nacThe Gaerttner LINAC Center
1St Inelastic to Scattering Ratio at 156 deg Experiment and Evaluations
• MCNP was used to calculate the as-measured elastic-to-inelastic neutron ratio for different evaluated nuclear data libraries
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.20.0
0.2
0.4
0.6
0.8
1.0Detector 4 Located at 156o
Inel
astic
/ El
astic
Rat
io
Incident Neutron Energy [MeV]
Experimental Data (Week 1) Experimental Data (Week 2) ENDF/B-VII.1 JEFF-3.1
Week 1
1500 1600 1700 1800 1900 2000 2100 2200 23000
500
1000
1500
2000
2500
3000
3500
4000
450012
156 deg
Energy [MeV]
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
19 nacThe Gaerttner LINAC Center
1St Inelastic to Scattering Ratio at 77 deg Experiment and Evaluations
• MCNP was used to calculate the as measured elastic to inelastic neutron ratio for different evaluated nuclear data libraries
1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.20.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6Detector 2 Located at 77o
Inel
astic
/ El
astic
Rat
io
Incident Neutron Energy [MeV]
Experimental Data (Week 2) ENDF/B-VII.1 JEFF-3.1
1500 20000
500
1000
1500
2000
2500
3000
3500
4000
450012
77 deg
Energy [MeV]
Coun
ts
Time of Flight [ns]
Fe56 Data ENDF/B-VII.1 ENDF/B-VI.8 JENDL-4.0 JEFF-3.1
20 nacThe Gaerttner LINAC Center
Thermal Scattering Overview • Analyzed experimental data for water and Medium Density
Polyethylene (MDPE) that was measured using SEQUOIA at SNS
• Performed measurements of High Density Polyethylene (HDPE) and Quartz (SiO2) using the Wide Angular-Range Chopper Spectrometer (ARCS) at SNS at SNS.
– Quartz measurements were done at 20, 300 550, 600 °C – HDPE was measured at 295 K and 5 K.
• LAMMPS code is utilized to calculate the phonon spectrum and scattering kernel for water and HDPE
21 nacThe Gaerttner LINAC Center
MDPE Data Processing Spectrometer Energy Resolution
• Use MCNP simulation of the incident energy spread.
0 20 40 60 80 100 120
2.0x102
4.0x102
6.0x102
8.0x102
1.0x103
1.2x103
1.4x103
1.6x103
1.8x103
2.0x103
Ei = 55 meVθ= 25 deg
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp. (MDPE) NJOY 99+MCNP 6.1
(ENDF/B-VII.1) MCNP 6.1 Library
(ENDF/B-VII.1)
0 20 40 60 80 100 120
2.0x102
4.0x102
6.0x102
8.0x102
1.0x103
1.2x103
1.4x103
1.6x103
1.8x103
2.0x103
Ei = 55 meVθ= 25 deg∆E/E = 0.03
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp. (MDPE) NJOY 99+MCNP 6.1
(ENDF/B-VII.1) MCNP 6.1 Library
(ENDF/B-VII.1)
Without energy resolution With energy resolution
22 nacThe Gaerttner LINAC Center
MDPE Experiment compared with different evaluated data files
• Comparison with several evaluations – More structure and larger differences in forward angles. – Possible issues with how we run NJOY/MCNP
0 20 40 60 80 100 120
101
102
103
Ei = 55 meVθ= 25 deg∆E/E = 0.03
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp. NJOY 99+MCNP 6.1
(ENDF/B-VII.1) MCNP 6.1 Library
(ENDF/B-VII.1) NJOY 99+MCNP 6.1
(JENDL 4.0) NJOY 99+MCNP 6.1
(JEFF 3.1)
0 20 40 60 80 100100
101
102
103Ei = 55 meVθ = 10 deg∆E/E= 0.03
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp. NJOY 99+MCNP 6.1
(ENDF/B-VII.1) MCNP 6.1 Library
(ENDF/B-VII.1) NJOY 99+MCNP 6.1
(JENDL 4.0) NJOY 99+MCNP 6.1
(JEFF 3.1)
23 nacThe Gaerttner LINAC Center
New Raw Experimental Data
• Polyethylene using ARCS-Wide Angle Spectrometer at SNS
10 20 30 40 50 60 70
1E-4
1E-3
0.01
0.1
1
Thickness = 0.15 mmθ = 10 degEI = 50 meV
Energy (meV)
Polyethylene Film (5K) Polyethylene Film (295K)
10 20 30 40 50 60 70
1E-4
1E-3
0.01
0.1 Thickness = 0.15 mmθ = 125 degEI = 50 meV
Inte
nsity
(arb
. uni
ts)
Energy (meV)
Polyethylene Film (5K) Polyethylene Film (295K)
24 nacThe Gaerttner LINAC Center
Quartz Crystal
• SiO2 was measured at multiple thicknesses – 0.3175 cm and 0.635 cm (1/8th and 1/4th inches) – Temperatures: 20 C, 300 C, 550 C, 600 C
10 20 30 40 50 60 70
1E-3
0.01
0.1
Thickness = 0.3175 cmθ = 10 degEI = 50 meV
Inte
nsity
(arb
. uni
ts)
Energy (meV)
Quartz (295K) Quartz (573K)
20 40 60 80 100 120 1401E-4
1E-3
0.01Thickness = 0.3175 cmθ = 55 degEI = 100 meV
Inte
nsity
(arb
. uni
ts)
Energy (meV)
Quartz (550 C) Quartz (600 C)
25 nacThe Gaerttner LINAC Center
Polyethylene - LAMMPS Simulation • Adaptive Intermolecular Reactive Empirical Bond Order
(AIREBO) potential for systems of carbon and hydrogen atoms. • Polyethylene (-CH2-)n chain.
– 400 molecules in chain, 1200 atoms. – 296 K temperature. – 0.1 fs (femtoseconds) time step – 20,000,000 steps = 2 ns ( This is the time simulated)
• FIX_PHONON – calculates the dynamical matrix from MD simulations based on observing
the displacement fluctuations.
• Output: binary files containing dynamical matrices whose eigenvalues are exactly the phonon frequencies at wavevector q.
26 nacThe Gaerttner LINAC Center
Polyethylene – LAMMPS post-analysis • Post-processing - PHANA code, distributed alongside
FIX_PHONON user package. • PHANA - calculates Phonon Density Of States (PDOS) by
evaluating eigenvalues of dynamical matrices at given wavevectors q.
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.400.0
0.5
1.0
1.5
2.0
2.5
3.0
Hill R.E., et al 2004 RPI PDOS
Phon
on D
ensit
y of
sta
tes
Frequency (eV)
27 nacThe Gaerttner LINAC Center
The Scattering Kernel - S(α,β) • LAMMPS phonon spectrum can be converted to a
scattering kernel S(α,β) • Using incoherent and Gaussian approximation: where is time in units ћ/kT seconds, with where ρ(β) is phonon density of states, PDOS.
,21),( )(ˆ tdtti eeS
γβ
πβα −
∞
∞−∫=
t
/2( ) ( ) 1 ,i tt P e e dβ βγ α β β∞
− −
−∞
= − ∫
,)2/sinh(2
)()(ββ
βρβ =P
28 nacThe Gaerttner LINAC Center
Polyethylene discussion – S(α,β) • PDOS NJOY99 (LEAPR)
• ACE files MCNP6.1 to generate double differential scattering cross section (DDSCS) to compare with the experiment. *M. Mattes and J. Keinert, Thermal Neutron Scattering Data for the Moderator Materials H2O, D2O and ZrHx in ENDF-6 Format and as ACE
Library for MCNP(X) Codes, IAEA INDC(NDS)-0470, 2005.
29 nacThe Gaerttner LINAC Center
Polyethylene DDSCS 15 degrees
0 20 40 60 80 100 120100
101
102
103
104
Ei = 55 meVθ = 15 deg
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp scaled x0.25 MCNP-ENDF/B-VII.1 MCNP-LAMMPS
30 nacThe Gaerttner LINAC Center
• Use NIST DAVE code to convert experimental data using one-phonon approximation, to Generalized Density of States G(E) which can be compared with the LAMMPS calculations.
• Some features are similar (at ~150 and ~350) but the agreement is not very good. • Improved LAMMPS calculations will include a full lattice cell (more than one chain that
was now used)
Measured Phonon Spectrum
0 100 200 300 400 5000.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
G(E
) [#/
eV]
Energy (meV)
ARCS PE 5K RPI-LAMMPS
31 nacThe Gaerttner LINAC Center
Experimental scattering kernel in MCNP First attempt for HDPE
• As expected the new scattering kernel agrees better with the experimental data
• Need to resolve the elastic peak and the impact of the spectrometer energy resolution.
0 20 40 60 80 100 120100
101
102
103
104
Ei = 55 meVθ = 15 deg
σ(E in
,Eou
t) [b
arns
/Sr/e
V]
Energy (meV)
Exp scaled x0.25 MCNP-ENDF/B-VII.1 MCNP-LAMMPS MCNP-ARCS GDOS
32 nacThe Gaerttner LINAC Center
Future Studies
• Proper identification of the reasons associated with the discrepancies.
• Fit the data with the new experimental data that will be acquired from ARCS at SNS.
• Better understanding of PDOS physics. • Perform LAMMPS simulations using different force
models and try to improve upon the current ones.
33 nacThe Gaerttner LINAC Center
LINAC 2020 Refurbishment and Upgrade Plan
• First meeting with SLAC team occurred last week – Discussed the requirement and options for the
refurbishment project. • Project timeline acceleration
– NR/KAPL is staging a significant procurement in FY14. – Additional funds will be available in FY15 to complete the
purchase of additional klystrons
34 nacThe Gaerttner LINAC Center
Recent Accomplishments • Completed scattering measurements and analysis for 56Fe
– Show new results for the ratio of the first inelastic state to elastic.
• Developing a new capability to measure capture cross sections in the mid energy (keV) range
– Detector array was installed – Flight path pipes vacuum system was installed. – Sample changer was installed. – DAQ and analysis software were developed. – Resolving problems with two of the detectors. – A test of the whole system with sample of B4C, C, Fe and Mo – Planned for another test measurement with Fe.
• Completed measurements of thermal scattering at SNS – Quartz measurements were done at 20, 300 550, 600 °C – HDPE was measured at 295 K and 5 K. – Data analysis and LAMPPS simulations are in progress
• LINAC 2020 refurbishment and upgrade plan in progress – First meeting with SLAC group occurred on the week of 3/16/2014 – Funding schedule accelerated, planning klystrons purchase
Top Related