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Applications and Interdisciplinary Research at TUNL

1.Homeland SecurityFaculty: M.W. Ahmed, H.R. Weller and Y. Wu; C.R. Howell and W.

TornowFacility: HIGSFunding: DHS/DNDO-ARI [2 grants: (1) polarized fission and (2) NRF]2. National Nuclear Security

Faculty: G. Mitchell; C.R. Howell and W. TornowFacility: DANCE at LANSCE, TUNL tandem lab and HIGSFunding: DOE/NNSA [3 grants: (1) neutron-induced reactions and (2) NRF]3. Energy Faculty: M.W. Ahmed and H.R. WellerFacility: TUNL tandem lab Funding: Tri Alpha Energies, Inc.4. Interdisciplinary Faculty: C.R. Howell; T.B. Clegg and H.J. KarwowskiFacility: TUNL tandem lab Funding: DOE/BER

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Photonuclear Reaction Measurements

at HIGSPhotonuclear Measurements on Actinides•To measure data for photon-induced nuclear reactions that are important for development of technologies for remote remote analysis of materials and interrogation of cargo using -ray beams and for advancing understanding of the structure of heavy nuclei.

•To educate the next generation of nuclear physicists in research areas and techniques relevant to national nuclear and homeland security.

Nuclear Resonance Fluorescence (NRF) MeasurementsFaculty: C.R. Howell and W. TornowFunding: DHS/DNDO-ARI and DOE/NNSA

Photofission Induced with Polarized -ray Beams Faculty: M.W. Ahmed and H.R. WellerFunding: DHS/DNDO-ARI

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Non-Intrusive Active Interrogation Systems (,’) data using Nuclear Resonance Fluorescence (NRF)

Courtesy LLNL

Tunable -ray source

0.0E+00

1.0E-04

2.0E-04

3.0E-04

0.0 2.0 4.0 6.0 8.0 10.0

Gamma-ray Energy (MeV)

Gam

ma-

ray

Tra

nsm

issi

on

Iron (35 cm thick) Lead (20 cm thick)

Need to characterize states in actinides that can be excited by dipole EM transitions with -ray energies 2 < E < 4 MeV

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Objectives of NRF Measurements

• Search for states that can be excited by dipole EM transitions (2 < E < 4 MeV)

• Determine: • Integrated cross section • Branching ratios• Spin and parity of the excited states (for nuclei with J=0+ ground

state)

• Isotopes: 240Pu, 237Np, 233U

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The Challenge of finding low-spin states at Ex > 2 MeV

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Challenge of finding low-spin states at Ex > 2 MeV

(non band states)

240Pu

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NRF Measurement Strategy

• Use Bremsstrahlung beam to conduct a search for dipole transitions over a broad -ray energy range, e.g. (2 < E < 4 MeV)

• Next use monoenergetic -ray beam to make high sensitivity measurements at selected energies based on results obtained with bremsstrahlung beams. Use linear polarization to provide information about the multipolarity of the observed -ray transitions.

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Search for low-spin states in 240Pu with bremsstrahlung beam

B.J. Quiter et al., Phys. Rev. C 86, 034307 (2012)Measurements made at the High Voltage Research Lab. at MITbremsstrahlung beam produced by 3-MeV electron beam

• Discovered 9 -ray transitions to the ground state

• Measured branching ratio between transition to the ground state and the 1st excited states

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Experiment Setup for NRF Measurements at HIGS

HPGe Detectors

Cu plateTarget

Flux Monitor

Pb wallBeam dumpcollimator

Paddles

Evacuated tube

HPGe Detectors

Cu plateTarget

Flux Monitor

Pb wallBeam dumpcollimator

Paddles HPGe Detectors

Cu plateTarget

Flux Monitor

Pb wallBeam dumpcollimator

Paddles

Evacuated tube

PIs: C.R. Howell and W. Tornow

240Pu: Example TOF and -ray Energy Spectra

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800 1000 1200 1400 1600 1800 2000 2200 2400 2600

0200400600800

1000120014001600

2450 2500 2550 2600 26500

50

100

150

200

Good RF Cut Accidental RF Cut

Detector 1 RF w/ Energy Cut Above 1850 keVC

oun

ts

Time (AU)

Detector 1 - Run 330, 334 (5 hr 21 min)Good vs. Accidental RF

2494

2504 25

23

2535

2547

2566

2578

208 T

l26

14.5

Co

unts

Energy (keV)

Good RF Accidental RF

800 1000 1200 1400 1600 1800 2000 2200 2400 2600

0200400600800

1000120014001600

2450 2500 2550 2600 26500

50

100

150

200

Good RF Cut Accidental RF Cut

Detector 1 RF w/ Energy Cut Above 1850 keV

Co

unts

Time (AU)

Detector 1 - Run 330, 334 (5 hr 21 min)Good vs. Accidental RF

2494

2504 25

23

2535

2547

2566

2578

208 T

l26

14.5

Co

unts

Energy (keV)

Good RF Accidental RF

E = 2.55 MeV, horizontal HPGe detector (5 hrs 21 min)

240Pu: Determination of Spin and Parity

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2450 2500 2550 2600 2650

0

50

100

150

200

250

300

350

Runs 330, 334 (5 hr 21 min) - 240Pu @ 2.55 MeVHorizontal and Vertical RF Subtracted

2492

2578

2566

2547

2535

25232504Cou

nts

Energy (keV)

Horizontal Vertical

Ex

Energy (keV)Jπ

1+/-

2+

0+

42.8

0.0

240Pu

E = 2.55 MeV(5 hrs 21 min)

Concept for material analysis – Polarized Photofission

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• Polarized -ray induces fission of target nuclei

• Prompt neutrons are detected both parallel and perpendicular to the plane of polarization of the incident -ray

φ = 90°

φ = 0°

-ray beam

Faculty: M.W. Ahmed and H.R. Weller

Setup for photofission measurements

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Implementation of concept

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E(MeV)

5.7 6.2

No Neutrons Fission Neutrons Fission + (,n) Neutrons

Fission Threshold (,n) Threshold

238U NeutronsClean Signal

o Typical energy range E = 5.8 - 7.0 MeV

o Only other stable isotopes which can produce neutrons at these energies are 2H and 9Be

o The neutron energy detection threshold is 1.5 MeVo All neutrons are fission neutrons

Example of neutron assembly of fissile vs nonfissile nucleus in Polarized Photofission

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Measurements of neutron assembly in polarized photofission

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fissile

nonfissile

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Applied and Interdisciplinary Research in the tandem lab at TUNL

1.(n,2nx) and (n, f) cross section measurements on actinidesFaculty: W. Tornow and C.R. Howell

2. Plant research with short-live radioisotopesFaculty: C.R. Howell

3. Water purification by filtrationFaculty: C.R. Howell

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Plant Physiology Studies Using Radioisotope Plant Physiology Studies Using Radioisotope TracingTracing

Duke Physics:Calvin Howell, Alexander Crowell, Laurie Cumberbatch, Brent Fallin

Duke Biology:Chantal Reid

Jefferson Lab: Brian Kross, Seung Joon Lee, Jack McKisson, John McKisson, Andrew Weisenberger, Wenze Xi, Carl Zorn

University of MD:Mark Smith

West Virginia University:Alexander Stolin

Federal Sponsors:DOE: Office of Nuclear PhysicsDOE Biological and Environmental ResearchNSF: Biological Infrastructure

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Evidence for Influence of Human Activities on Evidence for Influence of Human Activities on Atmospheric COAtmospheric CO2 2 LevelsLevels

“Industrial Revolution”

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Long-time scale Picture of Atmospheric CO2 Levels

Milanković cycles:Earth’s orbital eccentricity: 100 kyrsEarth’s axis tilt (22.1 ↔ 24.5): 42 kyrsEarth’s axis wobble: 23 kyrs

from Antarctic ice core samples

Current atm. CO2 concentration

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Research Objectives

to identify and measure the effects of changes in environmental conditions on the allocation of carbon (sugars) and nitrogen;

to measure the physical parameters in plant physiology models of substance translocation and allocation, e.g., phloem loading and root exudation;

to measure plant responses to herbivores; and

to measure dynamic change in photorespiration rate in response to changes in environmental conditions.

1. Primary food source on Earth

2. Helps regulate atmospheric CO2 levels

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Isotope production and use

≈100 mp + 14N 11C + α

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Plant Physiology Research using Radioisotope tracing

Collaboration with JLab detector groupLocal Participants:Faculty: Howell, Reid (Biology)

Research Scientist: Crowell

PhD Student: Cumberbatch

Goal: Explore dynamical response of plants to changes in its local environment and external resource availability

Published in Physics in Medicine and Biology (2012)

Radioisotopes produced in tandem lab Measurements made at the Phytotron (in

environment controlled growth chamber)

Larry Cumberbatch, Duke Medical Physics, PhD thesis

project

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PhytoPET System

• Developed at JLAB

• Based on H8500 PSPMT and pixelated LYSO crystals

• Flash ADC readout over Gb ethernet

• Multiple configurations possible

Weisenberger et al., NIM A, 718 (2013) 157.

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Corn Growth Conditions

• Young corn plants (~ 1-2 weeks old) labeled with 11CO2

• B73 variety – has a sequenced genome• Transplant into clear media (Gelzan) to

facilitate registration of root images

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Translocation of Sugars

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Quantitative Analysis

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v (1 → 2) ≈ 6.0 mm/min v (2 → 3) ≈ 0.1 mm/minv (3 → 4) ≈ 0.3 mm/min

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Characterization of membranes for water purification by Rutherford Backscattering Spectrometry (RBS) and Elastic

Recoil Detection (ERD) analyses

Students: Peter Attayek (UG), Eliot Meyer, Lin Lin, Grayson Rich, Joshua Powell Faculty: Orlando Coronell, Thomas Clegg Collaborators: Hugon Karwowski, Nalin Parikh

Attayek et al., Submitted for publication

(Left) A new target system was developed to enable analysis of organic samples by Rutherford backscattering spectrometry (RBS) and elastic recoil detection analyses

(Below) The target system is used to study the active layer of membranes for water desalination and reuse, including their elemental composition and charge density