What is it about?

We developed a novel laboratory device that is capable of measuring the intensity of a low-energy neutral atoms beam inside a vacuum test facility, independently of device calibration. Thus the name 'Absolute Beam Monitor'. It is based on coincident detection of neutral atoms reflected off a polished crystal surface. We report on the proof of concept and device characterization.

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Why is it important?

In space science, energetic neutral atoms imaging instruments need thorough instrument calibration in a vacuum test facility before launch. For accurate instrument calibration the neutral atoms beam in the test facility needs be characterized by measuring its particle flux. Measuring neutral beams is challenging because the atoms are electrically neutral and detection efficiency decreases at low energies.


The testing and characterization of the novel Absolute Beam Monitor device in the test facility was demanding and time-consuming: it needed fine-adjustment of the ion-source, the neutralization stage, and the ABM device. Suppression or removal of noise-signal was an ever-occurring task. And especially at very low beam energies (<30 eV) where we have the lowest count rates, very long acquisition times and very stable ion beams are required for sufficient and reliable statistics.

Jonathan Gasser
Universitat Bern

Read the Original

This page is a summary of: Absolute beam monitor: A novel laboratory device for neutral beam calibration, Review of Scientific Instruments, September 2022, American Institute of Physics, DOI: 10.1063/5.0092065.
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