1. Homeland Security
Faculty: M.W. Ahmed, H.R. Weller and Y. Wu; C.R. Howell and W. Tornow
Facility: HIGS
Funding: DHS/DNDO-ARI [2 grants: (1) polarized fission and (2) NRF]
2. National Nuclear Security
Faculty: G. Mitchell; C.R. Howell and W. Tornow
Facility: DANCE at LANSCE, TUNL tandem lab and HIGS
Funding: DOE/NNSA [3 grants: (1) neutron-induced reactions and (2) NRF]
3. Energy
Faculty: M.W. Ahmed and H.R. Weller
Facility: TUNL tandem lab
Funding: Tri Alpha Energies, Inc.
4. Interdisciplinary
Faculty: C.R. Howell; T.B. Clegg and H.J. Karwowski
Facility: TUNL tandem lab
Funding: DOE/BER
1

Photonuclear 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 g -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) Measurements
Faculty: C.R. Howell and W. Tornow
Funding: DHS/DNDO-ARI and DOE/NNSA
Photofission Induced with Polarized g -ray Beams
Faculty: M.W. Ahmed and H.R. Weller
Funding: DHS/DNDO-ARI
2

s ( g , g ’) data using Nuclear Resonance Fluorescence (NRF)
Iron (35 cm thick) Lead (20 cm thick)
3.0E-04
2.0E-04
1.0E-04
Tunable g
-ray source
Courtesy LLNL
0.0E+00
0.0
2.0
4.0
6.0
8.0
Gamma-ray Energy (MeV)
10.0
Need to characterize states in actinides that can be excited by dipole EM transitions with g
-ray energies 2 < E g
< 4 MeV
3

• Search for states that can be excited by dipole EM transitions (2 < E g
< 4 MeV)
• Determine:
• Integrated cross section
• Branching ratios
• Spin and parity of the excited states (for nuclei with J=0+ ground state)
• Isotopes: 240 Pu, 237 Np, 233 U
4

The Challenge of finding low-spin states at E x
> 2 MeV
5

Challenge of finding low-spin states at E x
(non band states)
> 2 MeV
240 Pu
6

• Use Bremsstrahlung beam to conduct a search for
dipole transitions over a broad g -ray energy range, e.g.
(2 < E g
< 4 MeV)
• Next use monoenergetic g -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 g -ray transitions.
7

240
• Discovered 9 g -ray transitions to the ground state
• Measured branching ratio between transition to the ground state and the 1 st excited states
B.J. Quiter et al., Phys. Rev. C 86, 034307 (2012)
Measurements made at the High Voltage Research Lab. at MIT bremsstrahlung beam produced by 3-MeV electron beam
8

Experiment Setup for NRF Measurements at HIGS
PIs: C.R. Howell and W. Tornow
9

200
150
Detector 1 - Run 330, 334 (5 hr 21 min)
Good vs. Accidental RF
Good RF
Accidental RF
100
50
240 Pu: Example TOF and
2450 2500 g -ray Energy Spectra
2550 2600
Energy (keV)
E g
1600
1400
1200
1000
800
600
400
200
0
Good RF Cut
Accidental RF Cut
800
200
150
1000 1200 1400 1600 1800 2000
Time (AU)
Detector 1 - Run 330, 334 (5 hr 21 min)
Good vs. Accidental RF
2200 2400
Good RF
Accidental RF
100
2650
2600
50
0
2450 2650 2500 2550
Energy (keV)
2600
Detector 1 RF w/ Energy Cut Above 1850 keV
Good RF Cut
Accidental RF Cut
1600
1400
1200
1000
800
600
400
200
0
800 1000 1200 1400 1600 1800 2000
Time (AU)
2200 2400 2600
10

240
350
300
250
200
150
100
50
0
2450
E
240
= 2.55 MeV(5 hrs 21 min)
Horizontal and Vertical RF Subtracted
2566
2578
J π
1 +/-
Energy (keV)
E x
Horizontal
Vertical
2492
2504
2523
2535
2547
2500 2550
Energy (keV)
2 +
0 +
240 Pu
42.8
0.0
2600 2650
11

Concept for material analysis – Polarized
Photofission
Faculty: M.W. Ahmed and H.R. Weller
φ = 90 °
• Polarized g -ray induces fission of target nuclei
• Prompt neutrons are detected both parallel and perpendicular to the plane of polarization of the incident g -ray
φ = 0 ° g
-ray beam
12

13

No Neutrons Fission Neutrons
Clean Signal
238 U Neutrons
Fission + ( g
,n) Neutrons
E g
(MeV)
5.7
6.2
Fission Threshold
( g
,n) Threshold o Typical energy range E g
= 5.8 - 7.0 MeV o Only other stable isotopes which can produce neutrons at these energies are 2 H and 9 Be o The neutron energy detection threshold is 1.5 MeV o All neutrons are fission neutrons
14

15

nonfissile fissile
16

1. (n,2nx) and (n, f) cross section measurements on actinides
Faculty: W. Tornow and C.R. Howell
2. Plant research with short-live radioisotopes
Faculty: C.R. Howell
3. Water purification by filtration
Faculty: C.R. Howell
17

Plant Physiology Studies Using Radioisotope Tracing
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 Physics
DOE Biological and Environmental Research
NSF: Biological Infrastructure
18

Evidence for Influence of Human Activities on
Atmospheric CO
2
Levels
“ Industrial Revolution ”
19

Long-time scale Picture of Atmospheric CO
2
Levels from Antarctic ice core samples
Current atm. CO
2 concentration
Milankovi ć cycles:
Earth ’ s orbital eccentricity: 100 kyrs
Earth ’ s axis tilt (22.1 ↔ 24.5): 42 kyrs
Earth ’ s axis wobble: 23 kyrs
20

1. Primary food source on Earth
2. Helps regulate atmospheric CO
2 levels
 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.
21

p + 14 N  11 C + α ≈100 m
22

Plant Physiology Research using Radioisotope tracing
Goal: Explore dynamical response of plants to changes in its local environment and external resource availability
 Radioisotopes produced in tandem lab
 Measurements made at the Phytotron (in environment controlled growth chamber)
Larry Cumberbatch, Duke Medical
Physics, PhD thesis project
Collaboration with JLab detector group
Local Participants:
Faculty: Howell, Reid (Biology)
Research Scientist: Crowell
PhD Student: Cumberbatch
Published in Physics in Medicine and Biology (2012)
23

• 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.
24

• Young corn plants (~ 1-2 weeks old) labeled with 11 CO
2
• B73 variety – has a sequenced genome
• Transplant into clear media (Gelzan) to facilitate registration of root images
25

26

1
2
3
4 v (1 → 2) ≈ 6.0 mm/min v (2 → 3) ≈ 0.1 mm/min v (3 → 4) ≈ 0.3 mm/min
27

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
(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
Attayek et al., S ubmitted for publication
28