Calibrating beam fluxes of a low-energy neutral atom beam facility.

Gasser, Jonathan; Galli, André; Wurz, Peter (2023). Calibrating beam fluxes of a low-energy neutral atom beam facility. The review of scientific instruments, 94(5) American Institute of Physics 10.1063/5.0140759

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Scientific detection and imaging instruments for low-energetic neutral atoms (ENA) onboard spacecraft require thorough pre-flight laboratory calibration against a well-characterized neutral atom beam source. To achieve this requirement, a dedicated test facility is available at the University of Bern, which is equipped with a powerful plasma ion source and an ion beam neutralization stage. Using surface neutralization, low-energy neutral atom beams of any desired gas species can be produced in the energy range from 3 keV down as low as 10 eV. As the efficiency of the neutralization stage is species and energy dependent, the neutralizer itself needs to be calibrated against an independent reference. We report on the calibration and characterization of this neutral atom beam source using our recently developed Absolute Beam Monitor (ABM) as a primary calibration standard. The ABM measures the absolute ENA flux independent of neutral species in the energy range from 10 eV to 3 keV. We obtain calibration factors of a few 100 cm-2 s-1 pA-1, depending on species at beam energies above about 100 eV, and a power-law decrease for energies below 100 eV. Furthermore, the energy loss of neutralized ions in the surface neutralizer is estimated from time-of-flight measurements using the ABM. The relative energy loss increases with ENA energy from low levels near zero up to 20%-35% at 3 keV, depending on atomic species. Having calibrated our neutral beam source allows for accurate calibration of ENA space instruments.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Gasser, Jonathan, Galli, A, Wurz, Peter

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

1089-7623

Publisher:

American Institute of Physics

Language:

English

Submitter:

Pubmed Import

Date Deposited:

22 May 2023 10:44

Last Modified:

22 May 2023 10:52

Publisher DOI:

10.1063/5.0140759

PubMed ID:

37204280

BORIS DOI:

10.48350/182701

URI:

https://boris.unibe.ch/id/eprint/182701

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