SG11201809453SA - Cold cathode ionization vacuum gauge with multiple cathodes - Google Patents

Abstract

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (43) International Publication Date 09 November 2017 (09.11.2017) WIP0 I PCT omit VIII Hot 01°111E11E oil oimIE (10) International Publication Number WO 2017/192352 Al (51) International Patent Classification: HO1J 41/06 (2006.01) GOlL 21/34 (2006.01) (21) International Application Number: PCT/US2017/029829 (22) International Filing Date: 27 April 2017 (27.04.2017) (25) Filing Language: English (26) Publication Language: English (30) Priority Data: 62/330,308 02 May 2016 (02.05.2016) US (71) Applicant: MKS INSTRUMENTS, INC. [US/US]; 2 Tech Drive, Suite 201, Andover, MA 01810 (US). (72) Inventors: SWINNEY, Timothy, C.; 2856 Des Moines Drive, Fort Collins, CO 80525 (US). PERCY, Clinton, L.; 7742 Country Rd. 72, Windsor, CO 80550 (US). MARION, Duane, W.; 2818 Marble Lane, Superior, CO 80027 (US). KELLY, Brandon, J.; 1317 Lupine Court, Longmont, CO 80503 (US). (74) Agent: SMITH, James, M. et al.; HAMILTON, BROOK, SMITH & REYNOLDS, P.C., 530 Virginia Rd, P.o. Box 9133, Concord, MA 01742-9133 (US). = (81) Designated States (unless otherwise indicated, for every kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DJ, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KH, KN, KP, KR, KW, KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG). Published: — with international search report (Art. 2 I (3)) W O 20 17 / 19 235 2 Al (54) Title: COLD CATHODE IONIZATION VACUUM GAUGE WITH MULTIPLE CATHODES (57) : A cold cathode ionization gauge includes multiple cathodes providing different spacings between the cathodes and an anode. The multiple cathodes allow for pressure measure- ments over wider ranges of pressure. A first cathode with a larger spacing may provide current based on Townsend discharge; whereas, a second cathode having a smaller spacing may provide current based on both Townsend discharge at higher pressures and on Paschen's Law discharge at still higher pressures. A feature on the second cathode may support Paschen's Law discharge. Large resistances between the cathodes and a return to power supply enable control of output profiles to extend the pressure ranges with accurate responses and avoid output minima. Pressure measurements may be made based on currents from respective cathodes dependent on the outputs 210 of the cathodes through the wide pressure range of measurement. The multiple cathodes may al- so provide measurements that avoid the discontinuities found in current outputs of the respective 1212 cathodes. FIG. 12