y. danon, e. liu, a. daskalakis, b. mcdermott c. … blain . dave williams . adam daskalakis . brian...

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


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


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


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





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


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


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


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


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


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


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


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


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


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


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]



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]


1800 1900 2000 2100 2200 23000

500

1000

1500

2000

2500

3000

3500

40001

153 deg

Energy [MeV]

Coun

ts

Time of Flight [ns]



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


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]



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]



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


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)

Without energy resolution With energy resolution


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) 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) NJOY 99+MCNP 6.1

(JENDL 4.0) NJOY 99+MCNP 6.1

(JEFF 3.1)


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)


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)


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.


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)


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


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.


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


• 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


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


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.


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


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

y. danon, e. liu, a. daskalakis, b. mcdermott c. … blain . dave williams . adam daskalakis . brian...

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