Recent actinide nuclear data efforts with the DANCE 4π BaF₂ array

Abstract

Abstract. Much of the recent work in the DANCE collaboration has focused on nuclides of interest to stockpile stewardship, attribution science and the advanced fuel cycle initiative. As an example, we have recently begun a program to produce high precision measurements of the key production and destruction reactions of important nuclear fuel elements and radiochemical diagnostic isotopes. The neutron capture targets that have been fielded under this program include several isotopes of uranium, plutonium and americium. However, neutron capture measurements on many of the actinides are complicated by the presence of γ-rays arising from low energy neutron-induced fission. To overcome this difficulty we have designed and implemented a dual parallel-plate avalanche counter fission-tagging detector. This design provides a high efficiency for detecting fission fragments and is self-contained to allow loading of pre-assembled target/detector assemblies into the neutron beam line at DANCE. An outline of the recent experimental program will be presented as well as preliminary results from neutron capture measurements on 234,235,236 U. Planned measurements on 238,239 Pu will also be discussed.

Recent results using the DANCE detector at Los Alamos

“…A fission-tagging detector is needed to separate gammas following fission from those due to capture. For DANCE, we have developed a 5 cm diameter parallel-plate avalanche counter 7 to fit inside the DANCE beam pipe. Low-energy resonance data on 235 U from a test run are shown in Figure 3.…”

Enhancing the Detector for Advanced Neutron Capture Experiments

“…Parallel-Plate Avalanche Counter (PPAC) detectors have been used with DANCE in the past as fission tagging detectors to separate the fission gamma component from the capture signal [14,15]. While this has been successful, the PPAC signal was shaped with analog electronics to conform to the filtering algorithms for the BaF 2 signals, a crude, if effective, approach.…”

Review of Livermore-led neutron capture studies using DANCE

“…Los Alamos National Laboratory, in a collaboration with Lawrence Livermore National Laboratory, has developed a fission-tagging detector, [12] which reduces the "background" from the fission and α-decay events during (n,γ) measurements. For the capture reactions, most γ rays associated with the (n,f) reactions can be removed using the fission tagging detector.…”