Session Y11: Mini-Symposium: Nuclear Physics for Energy, Medicine, and Security

Nuclear Physics for Nonproliferation and Safeguards Applications

Antineutrinos present a possible solution to nuclear safeguards and nonproliferation. Their emission is a direct signature of fission, and can help evaluate the operational status, fissile evolution, and fuel loading of nuclear reactors. Previous experimental campaigns dedicated to either fundamental science or nonproliferation have been integral toward driving the conceptualization of antineutrino applications closer towards a deployable tool through above-ground detectors using highly segmented arrays. Current efforts towards long-range reactor monitoring and exclusion are exploring the feasibility and constraints of detecting antineutrinos from remote nuclear facilities. Recently, efforts to engage end-users through community-based discussions focused on utility have helped to narrow the concentration of use-cases for antineutrino detections and define requirements for detector systems suitable for deployment.   

Studying the decay data of I-130

Detection of fission products (FPs) is at the basis of several applications, from reactor science, to non-proliferation and nuclear forensics. In most cases, an accurate quantification of FPs is only possible when the decay data of these isotopes - such as half-life, characteristic gamma-ray energies and intensities - are well known. This is not always the case, and - for many FPs - the current knowledge of decay data comes from measurements that were performed when gamma-ray spectroscopy was in its infancy.

A new campaign to precisely determine gamma-ray intensities of selected FPs is currently underway at Brookhaven National Laboratory. In this work, we present the results for I-130, a so-called “blocked” FP, of particular interest for nuclear forensics. Measuring the amount of I-130 relative to other well-known FPs can, in fact, provide valuable information about the initial fission event that produced it. 

I-130 was produced via the Te-130(p,n) reaction at the BNL Tandem Van de Graaff facility, and assayed at Argonne National Laboratory using the Gammasphere array. The results of precision intensities measurement and a revised decay scheme will be presented.   

New approach to precisely measure gamma-ray intensities for long-lived fission products

We have recently demonstrated a new experimental approach to precisely determine the gamma-ray intensities following the beta decay of long-lived fission products. For national-security applications, such as stockpile stewardship and nuclear forensics, one of the most straightforward and reliable ways to determine the number of fissions that occurred in a chain reaction is done via detection of the emitted gamma rays. The focus of this talk is on recent measurements to improve the nuclear-decay data for the fission products ⁹⁵Zr, ¹⁴⁴Ce, and ¹⁴⁷Nd. For these isotopes, and many other fission products, the gamma-ray intensities are desired to high precision for these national-security applications. Our approach consists of implanting fission-product samples into a thin carbon foil using low-energy mass-separated ion beams from the CARIBU facility and then performing beta counting using a custom-made 4-pi gas proportional counter in coincidence with gamma-ray spectroscopy using the precisely-calibrated HPGe detector at Texas A&M University. Recent results for ⁹⁵Zr, ¹⁴⁴Ce, and ¹⁴⁷Nd will be presented and future plans will be discussed.   

Improving the decay data of 186Ir for use as a radiopharmeceutical

The nucleus 186Ir is a potential radio-pharmaceutical currently under study to be used in cancer treatment due to its Auger-emitting  properties.  Accurate knowledge of the decay of 186Ir will be necessary in calculations for production of the nucleus, dose estimation, and shielding for transportation and routine handling. However, the current literature  data on 186Ir decay  stems from an early 1970’s measurement which can be much improved upon with the use of advanced gamma-ray spectroscopy techniques.  For this work, 186Ir was obtained as the granddaughter of 186Au which was produced using a beam of 19F at 140MeV on a 174Yb target.  The decay was measured using the Gammasphere Array at Argonne National Laboratory.  The high statistics dataset allowed for the observation of many new levels and transitions and the determination of precise intensities.  The revised decay scheme will be presented and its impact on dose estimates discussed.   

Medical Radioisotope Production Using Inverse Kinematics

A novel approach to produce medically important radionuclides using inverse kinematics has been developed at the Cyclotron Institute at Texas A&M University. The methodology consists in impinging a heavy-ion beam of appropriate energy on a light gas target and collecting the isotope of interest, focused along the beam direction, on a foil catcher after the target. As the quantity of the material required to prepare heavy-ion beam is considerably smaller than that used in the standard solid target approach, material costs are expected to be reduced through this methodology. The theranostic radionuclide ⁶⁷Cu (T_1/2 = 62 h) were produced through the reaction of a ⁷⁰Zn beam at 15 MeV/nucleon with a H₂ gas target. The ⁶⁷Cu radionuclide alongside other coproduced isotopes, was collected after the gas target on an aluminum catcher foil and their radioactivity was measured by off-line γ-ray analysis. Pursuing the investigation, the well-known ⁹⁹Mo/^99mTc generator system was also tested with a beam of ¹⁰⁰Mo at 12 MeV/nucleon on ⁴He gas target for three different gas pressures. The methodology has been tested with success. The production of the ⁶⁷Cu and ⁹⁹Mo were predominant in comparison with the radio impurities.   

Investigating the Energy Dependence of 239Pu Fission Yields

Experimental fission product yields (FYs) from neutron-induced fission of 239Pu were retrieved and compiled to investigate their energy dependence, a quantity of interest for the understanding of the fission process, as well as for applications (such as nuclear forensics and reactors physics). Spanning 70 years, the compilation resulted in a total of 303 FY datasets, including both cumulative and independent FYs. These datasets were corrected, filtered, and normalized to accurately depict FYs as a function of incident neutron energy. The experimental data was then compared to the GEF model, a prominent theoretical fission model. For direct comparison of experimentally determined cumulative FYs and the theoretical data, the GEF independent FYs were converted to cumulative FYs via ENDF/B-VIII.0 decay data. This work will show the experimental FY trends with incident neutron energy and compare them with the GEF model.