GAGG Radiation Instrumentation (GARI)

Neutron radiation detection instrument-1A (NeRDI-1A)

“…The instrument has operated nearly continuously since integration onto the ISS in March 2023, and we have begun to analyze early orbit data. Future work will include analysis of the spectral data obtained from the TLYC scintillator (with a particular focus on the 6 Li neutron capture peak) as well as characterization of performance over the entire mission of STP-H9; the planned mission life is one year, after which time the platform may be disposed of via controlled destructive re-entry. A follow-on…”

“…Due to the increased demand for 3 He neutron detectors for homeland security purposes after the events of September 11, 2001, and the declining production of 3 He with the reduction of the nuclear weapons stockpile, significant research has gone into neutron detection technologies to replace 3 He. Among the technologies that have been developed as part of this effort are dual-response scintillators and solid-state neutron detectors, both of which utilize the relatively high cross section of the 6 Li(n,α) 3 He reaction for thermal neutrons. For space-based applications, these new technologies are particularly attractive when compared to 3 He proportional counters as they avoid issues associated with pressurized gases andwhen coupled with silicon photomultipliers (SiPMs), in the case of scintillatorscan be operated at bias voltages on the order of tens of volts rather than hundreds of volts.…”

“…A third detector, a thin sliver of EJ-270 3 plastic scintillator, is included for high-rate environments. NeRDI-1A was developed for integration onto the International Space Station (ISS) as part of the Department of Defense Space Test Program (STP) mission STP-H9, and its design leverages previous NRL work on SIRI 4,5 and GARI 6 instruments. The details of the instrument design, the concept of operations, and early orbit data are discussed below.…”

On-orbit results of the GAGG radiation instruments

“…Only a brief description of the instrument is provided here. A more detailed summary of the instruments design can be found elsewhere [12]. The compact GARI instrument is packaged in an aluminum enclosure measuring 15.7 cm x 14.5 cm x 11.4 cm, shown in Figure 2 (left) and has a total mass of 2.8 kg.…”