Publication detail

Impact of Supersonic Flow in Scintillator Detector Apertures on the Resulting Pumping Effect of the Vacuum Chambers

MAXA, J. NEDĚLA, V. ŠABACKÁ, P. BINAR, T.

Original Title

Impact of Supersonic Flow in Scintillator Detector Apertures on the Resulting Pumping Effect of the Vacuum Chambers

Type

journal article in Web of Science

Language

English

Original Abstract

The article describes the combination of experimental measurements with mathematical–physics analyses in flow investigation in the chambers of the scintillator detector, which is a part of the environmental scanning electron microscope. The chambers are divided with apertures by small openings that keep the desirable pressure differences between three chambers: The specimen chamber, the differentially pumped intermediate chamber, and the scintillator chamber. There are conflicting demands on these apertures. On the one hand, the diameter of the apertures must be as big as possible so that they incur minimal losses of the passing secondary electrons. On the other hand, it is possible to magnify the apertures only to a certain extent so the rotary and turbomolecular vacuum pump can maintain the required operating pressures in separate chambers. The article describes the combination of experimental measurement using an absolute pressure sensor and mathematical physics analysis to map all the specifics of the emerging critical supersonic flow in apertures between the chambers. Based on the experiments and their tuned analyses, the most effective variant of combining the sizes of each aperture concerning different operating pressures in the detector is determined. The situation is made more difficult by the described fact that each aperture separates a different pressure gradient, so the gas flow through each aperture has its own characteristics with a different type of critical flow, and they influence each other, thereby influencing the final passage of secondary electrons detected by the scintillator and thus affecting the resulting displayed image.

Keywords

Ansys Fluent; ESEM; scintillation detector; critical flow; one-dimensional flow theory; aperture; pressure sensor

Authors

MAXA, J.; NEDĚLA, V.; ŠABACKÁ, P.; BINAR, T.

Released

18. 5. 2023

Publisher

MDPI

Location

BASEL

ISBN

1424-8220

Periodical

SENSORS

Year of study

23

Number

10

State

Swiss Confederation

Pages from

1

Pages to

38

Pages count

38

URL

https://www.mdpi.com/1424-8220/23/10/4861

Full text in the Digital Library

http://hdl.handle.net/11012/244944

BibTex

@article{BUT183736,
  author="Jiří {Maxa} and Vilém {Neděla} and Pavla {Šabacká} and Tomáš {Binar}",
  title="Impact of Supersonic Flow in Scintillator Detector Apertures on the Resulting Pumping Effect of the Vacuum Chambers",
  journal="SENSORS",
  year="2023",
  volume="23",
  number="10",
  pages="1--38",
  doi="10.3390/s23104861",
  issn="1424-8220",
  url="https://www.mdpi.com/1424-8220/23/10/4861"
}