Ionization Chamber Design, Development, and Testing for the UNM Fission Fragment Spectrometer

Fission fragment and product inventories play an important role in many areas of nuclear science from simulation of fissioning systems to active and passive interrogation of nuclear materials. The characteristic properties of fission fragment distributions are currently lacking in experimental data. New data is needed to reduce the uncertainty in the current standard data and to expand on current data for other incident neutron energies. To attain the goal of new fission fragment data, the Spectrometer for Ion Detection in Fission Research (SPIDER) project is currently underway at Los Alamos National Labortory (LANL). The SPIDER project is intended to be a multi-armed spectrometer that will use high resolution measurements and event by-event analysis to add to the library of nuclear fission data. Our group at the University of New Mexico is working as a collaborator on the SPIDER project to achieve a mass resolution of 1 amu with our own UNM fission fragment spectrometer. Mass is determined by combining particle-by-particle data from a time-of-flight detector and an ionization chamber energy detector. Our UNM spectrometer will also be capable of gathering fission fragment charge (Z) data, due to the addition of an active cathode in the ionization chamber. Preliminary testing has already taken place at the LANSCE facility at Los Alamos, resulting in uncorrelated energy and timing data. Futher data will be taken at a later date at the LANSCE facility. The UNM ionization chamber has achieved uncorrelated, uncalibrated preliminary results at LANL for fission fragment energy distributions at the LANSCE facility. A current energy resolution of 1.5% at high pressures for alpha particles has been measured. In addition to energy measurements, the ionization chamber has achieved measuring the range of alpha particles and both light and heavy fission fragments through use of an active cathode. Further characterizing has also been done on the ionization chamber to better understand the effects of internal andexternal variables on energy resolution and particle range measurement

The Lunar Polar Hydrogen Mapper (LunaH-Map) Mission

The Lunar Polar Hydrogen Mapper (LunaH-Map) mission will map hydrogen enrichments within permanently shadowed regions at the lunar south pole using a miniature neutron spectrometer. While hydrogen enrichments have been identified regionally from previous orbital missions, the spatial extent of these regions are often below the resolution of the neutron instruments that have flown on lunar missions. LunaH-Map will enter into an elliptical, low altitude perseline orbit which will enable the mission to spatially isolate and constrain the hydrogen enrichments within permanently shadowed regions. LunaH-Map will use a solid iodine ion propulsion system, X-Band radio communications through the NASA Deep Space Network, star tracker, C&DH and EPS systems from Blue Canyon Technologies, solar arrays from MMA Designs, LLC, mission design and navigation by KinetX. Spacecraft systems design, integration, qualification, test and mission operations are performed by Arizona State University

LunaH-Map: Revealing Lunar Water with a New Radiation Sensor Array

A new type of neutron and gamma-ray spectrometer called the Miniature Neutron Spectrometer (Mini-NS) has been developed, assembled, qualified and delivered as part of the Lunar Polar Hydrogen Mapper (LunaH-Map) cubesat mission. The LunaH-Map spacecraft is currently manifested as a secondary payload on the Space Launch System (SLS) Artemis-1 rocket. LunaH-Map will deploy from Artemis-1 and enter a low altitude perilune elliptical orbit around the Moon. The Mini-NS will measure the lunar epithermal neutron albedo, and measurements around perilune will be used to produce maps of hydrogen enrichments and depletions across the lunar South Pole region including both within and outside of permanently shadowed regions (PSRs). The Min-NS was designed to achieve twice the epithermal neutron count rate of the Lunar Prospector Neutron Spectrometer (LP-NS). The instrument response was characterized through the collection of pre-flight neutron counting data with a Cf-252 neutron source at Arizona State University across hundreds of power cycles, as well as across the expected temperature range. The instrument spatial response was characterized at the Los Alamos National Laboratories (LANL) Neutron Free In-Air Facility. The LunaH-Map Mini-NS was designed to fit within the cubesat form-factor and uses two detectors with eight sensor heads that can be operated independently. For future missions with different science goals that can be achieved with epithermal neutron detection, the number of Mini-NS sensor heads can easily be modified without requiring a complete re-design and re-qualification