Wien filter

A Wien filter also known as a velocity selector is a device consisting of perpendicular electric and magnetic fields that can be used as a velocity filter for charged particles, for example in electron microscopes and spectrometers.^[1]^[2] It is used in accelerator mass spectrometry to select particles based on their speed. The device is composed of orthogonal electric and magnetic fields, such that particles with the correct speed will be unaffected while other particles will be deflected. It is named for Wilhelm Wien who developed it in 1898 for the study of anode rays.^[3]^[4] It can be configured as a charged particle energy analyzer, monochromator, or mass spectrometer.^[1]^[2]

^ ^a ^b H. H. Rose (2008). "Optics of high-performance electron Microscopes". Science and Technology of Advanced Materials. 9 (1): 014107. Bibcode:2008STAdM...9a4107R. doi:10.1088/0031-8949/9/1/014107. PMC 5099802. PMID 27877933.
^ ^a ^b Galejs, A. (1978). "Focusing and dispersing properties of a stigmatic crossed-field energy analyzer" (PDF). Journal of Vacuum Science and Technology. 15 (3): 865–867. Bibcode:1978JVST...15..865G. doi:10.1116/1.569615.
^ Wien, W. (1898). "Untersuchungen über die electrische Entladung in verdünnten Gasen" (PDF). Annalen der Physik. 301 (6): 440–452. Bibcode:1898AnP...301..440W. doi:10.1002/andp.18983010618.
^ Wien, Karl (1999). "100 years of ion beams: Willy Wien's canal rays" (PDF). Brazilian Journal of Physics. 29 (3): 401–414. Bibcode:1999BrJPh..29..401W. doi:10.1590/S0103-97331999000300002.

[rose-1] H. H. Rose (2008). "Optics of high-performance electron Microscopes". Science and Technology of Advanced Materials. 9 (1): 014107. Bibcode:2008STAdM...9a4107R. doi:10.1088/0031-8949/9/1/014107. PMC 5099802. PMID 27877933.

[Galejs1978-2] Galejs, A. (1978). "Focusing and dispersing properties of a stigmatic crossed-field energy analyzer" (PDF). Journal of Vacuum Science and Technology. 15 (3): 865–867. Bibcode:1978JVST...15..865G. doi:10.1116/1.569615.

[Wien_1898-3] Wien, W. (1898). "Untersuchungen über die electrische Entladung in verdünnten Gasen" (PDF). Annalen der Physik. 301 (6): 440–452. Bibcode:1898AnP...301..440W. doi:10.1002/andp.18983010618.

[Wien1999-4] Wien, Karl (1999). "100 years of ion beams: Willy Wien's canal rays" (PDF). Brazilian Journal of Physics. 29 (3): 401–414. Bibcode:1999BrJPh..29..401W. doi:10.1590/S0103-97331999000300002.

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