US 11,971,386 B2
Monitoring radical particle concentration using mass spectrometry
Chenglong Yang, Fremont, CA (US); Jimmy Liu, San Jose, CA (US); and James Edward Blessing, Morgan Hill, CA (US)
Assigned to MKS Instruments, Inc., Andover, MA (US)
Filed by MKS Instruments, Inc., Andover, MA (US)
Filed on Dec. 16, 2021, as Appl. No. 17/644,704.
Claims priority of provisional application 63/130,257, filed on Dec. 23, 2020.
Prior Publication US 2022/0196597 A1, Jun. 23, 2022
Int. Cl. H01J 49/28 (2006.01); G01N 27/623 (2021.01)
CPC G01N 27/623 (2021.01) [H01J 49/282 (2013.01)] 48 Claims
OG exemplary drawing
 
1. A system for monitoring radical particles comprising:
a test chamber configured to be coupled to a flow channel adapted to transmit a gas, the test chamber defining an aperture connecting the test chamber and the flow channel, the aperture configured to permit a subset of the gas to enter the test chamber from the flow channel;
an ionizer positioned within the test chamber, the ionizer configured to generate radical ions from radical particles of the subset of the gas; and
a mass spectrometer configured to measure a quantity of the radical ions.