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1、JIS JAPANESE INDUSTRIAL STANDARD Measuring Methods of Low Pressures by Hot Cathode and Cold Cathode Ionization Gauges JIS Z 8752-1989 Translated and Published by Japanese Standards Association UDC 531.788.7 Printed in Japan Copyright Japanese Standards Association Provided by IHS under license with
2、JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- i J I S Z*8752 89 4933608 0079778 O = I - I In the event of any doubt arising, the original Standard in Japanese is to be final author
3、ity. Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- - J I S Z*8752 89 D 4933608 0079779 2 Kind of gauge U
4、DC 531.788.7 JAPANESE INDUSTRIAL STANDARD JIS Measuring Methods of Low Pressures by Hot Cathode Z 8752-1989 and Cold Cathode Ionization Gauges Range of measuring pressures 1. Scope using hot cathode and cold cathode ionization gauges, hereafter referred to as the “gauges“. 2. Definition specified in
5、 JIS Z 8126, JIS Z 8127, and JIS Z 8128. This Japanese Industrial Standard specifies the general methods of measurement for low pressures The meanings of the main terms used in this Standard shall be as specified below, except where (1) envelope A part of the gauge head, consisting of a receptacle w
6、hich accommodates the electrodes. (2) vacuum system The vacuum device to be the object of pressure measurement. Hot cathode ionization gauge Cold cathode ionization gauge (3) controlled measuring unit A measuring instrument having both a power source for operating the gauge head and the function of
7、measuring the current or the like and indicatingthe pressure. Triode type 10-l to lo-5 B-A 10-1 to io4 Medium vacuum service 10 to Penning 1 to lo4 Magnetron 10-1 to lo4 Applicable Standards: JIS Z 8126-Vacuum Technology - Vocabulary (General Terms) JIS Z 8127-Vacuum Technology - Vocabulary (Vacuum
8、Pumps and Related Terms) JIS Z 8128-Vacuum Technology - Vocabulary (Vacuum Gauges and Related Terms) JIS Z 8750-Methods of Calibration ?or Vacuum Gauges Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale,
9、 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*8752 89 Y933608 0079780 9 2 2 8752-1989 4.2 Hot Cathode Ionization Gauge (1) Constitution of Gauge Head The constitution of the gauge head of hot cathode ionization The gauge head consists of a hot
10、 cathode emitting thermion, an gauges and the principle of measurement shall be as follows: electron collecting electrode which accelerates and collects these electrons, and an ion collecting electrode which collects the produced ions. Gauge heads include normal gauge head equipped with an envelope
11、and gauge head forming a nude gauge which lacks the envelope and whose electrodes are directly attached to the flange, The accelerated electrons collide with the gas molecules and ionize them, Because, under definite conditions, the number of ions produced in unit time are propor- tional to the magn
12、itude of the electron current and the density of the gas, the pressure is deter- mined from the ion current produced by collecting these produced ions. This relation is shown in formula (1). (2) Principle of Measurement ( 1 ) . p = - . 1 li s I , where, p : pressure (Pa) it : ioncurrent (A) I , : el
13、ectron current (A) s : ionization gauge coefficient (Pad1) Remark The ionization gauge coefficient varies with the kind of gas, construction of electrodes, and operating conditions. 4.3 Cold Cathode Ionization Gauge (1) Constitution of Gauge Head (2) Principle of Measurement The constitution of the
14、gauge head of cold cathode ionization The gauge head consists of electrodes for electric discharge and a gauges and the principle of measurement shali be as follows: magnet for making the discharge continuous. magnetic field. Because, under definite conditions, the discharge current is approximately
15、 propor- tional to the density of the gas, the pressure is determined from this discharge current. This rela- tion is shown in formula (2). Electric discharge is produced between electrodes placed in a . p = L s ( 2 ) where, Id : discharge current (A) s : sensitivity Coefficient (A.P-) Remark The se
16、nsitivity coefficient varies with the kind of gas, construction of the electrodes, strength of the magnetic field, and operating conditions. 5. Measuring Method Because, in a vacuum system, generally, the pressure varies with the position, it is necessary to install the gauge head close to the desir
17、ed position of measurement. Because the indicated pressure value sometimes differs according to the method of connection, measurement shall be performed with attention to the following points. (1) The opening face of the conducting tube of the gauge head shall be made perpendicular to the conducting
18、 tube axis. (2) The conducting tube of the gauge head or the gauge-head connecting part shall be installed perpendicularly to the side wall at the measuring position, as shown in Figs. 1 to 3. The opening face shall be made agree with the wall surface of the vacuum system, as a rule. 5.1 Connection
19、of Gauge Head Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*4752 89 4933b08 0079781 O 3 Z 8752-1
20、989 Further, where there is a flow in the vacuum system, the opening face of the conducting tube should desirably be made perpendicular to the direction of flow. Fig. 1. Example of Connecting Method Using O-Ring -Side wall at measuring position Opening face Fig. 2. Example of Connecting Method Using
21、 Kovar Connection Side wal at measuring Opening face position Fig. 3. Example of Connection in Nude Gauge Gauge-head connecting part / fl ,-Side w a l l at measuring position Opening face Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001
22、, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- 4 Z 8752-1989 (3) The diameters and lengths of the conducting tube and gauge-head connecting part shall be made the same as those used in calibration, as a rule. ( 4 ) Ga
23、skets or the like used for connecting the gauge head shall be made of a material with little degassing and resistant to the rise of temperature accompanying the outgassing of the gauge head. No rubber tubes or conducting tubes of stained inside shall be used on the mid-way. No materials with much de
24、gassing, such as grease, shall be used. Further, for the measurement of pressure in a super high vacuum region, it is preferable to use the Kovar connection or a nude gauge. I I 52 Measuring Procedure 5 . 2 . 1 Hot Cathode Ionization Gauge Where a pressure of Pa or higher is being measured, the meas
25、ured value shall generally be represented by the reading taken 5 min or longer after ignition of the hot cathode. outgassing the electrodes and envelope by electron shock or direct passing of current and after the indication has stabilized, It is desirable to perform the subsequent measurement in th
26、e continued ignited condition. Where the gauge head is not contaminated, the gauge shall be continuously ignited and the reading when the indication has stabilized shall be taken as the measured value. Where a pressure of lower than Pa is being measured, measurement shall be performed after 5.2.2 Co
27、ld Cathode Ionization Gauge After the gauge is started to operate, the reading when the indication has stabilized shall be taken as the measured value. The gauge shall preliminarily be calibrated in the prescribed operating condition. Because the indication varies with the operating and environmenta
28、l conditions, measurement shall be made with attention to the following points. 5.3 Measuring Conditions (1) Because the electron current, electrode voltage, magnetic field intensity, relative positions of the magnetic poles and electrodes, and the like have remarkable effects on the sensitivity of
29、the gauge, the conditions determined at the time of calibration shall be followed. (2) The atmospheric temperature for the gauge head shall be made the same as in the calibration. (3) Where there is the risk of the gauge head being exposed to a strong electric or magnetic field, or being irradiated
30、by strong radiation, counter measures such as shading of the gauge head shall be taken to reduce such effects. (4) Where the vacuum system contains inside a strong source of emission of electrons or ions, counter measures such as shading of the probe shall be taken to reduce such effects. (5) Counte
31、r means shali be provided to protect the gauge head envelope from direct exposure to a strong wind and temperature radiation, (6) Where the intended location of measurement is at a remarkably high or low temperature, the temperature shall be recorded to allow a correction for thermal transition when
32、 required. Reference: I Where the change in pressure is speedy, sometimes a delay occurs in the indication because of the adsorption and desorption of the gas, resulting in incorrect indication of pressure. 6. Inspection and Calibration Gauges shall be inspected periodically, and, calibrated when re
33、quired. However, where there is the danger of contamination of the gauge head, where there is the suspect of occurrence of deformation in the electrodes or magnetic poles caused by a mechanical shock or the like, where an especially precise measurement is intended, and in like cases, an inspection a
34、nd calibration shall be made each time. 6.1 Time of Inspection and Calibration I 6.2 Inspection Items and Inspection Methods Inspection shall be made for the following items by the following methods to confirm that the gauge head and controlled measuring unit satisfy the conditions deter- mined at t
35、he time of calibration, I Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*8752 89 = 4933608 007978
36、3 4 5. Z 8752-1989 ( 1 ) Staining of Gauge Head and Deformation of Electrodes and Magnetic Poles The staining of the gauge head and the deformation of the electrodes and magnetic poles of the probe and the change in their relative positions shall be examined visually if it is possible. (2) Electric
37、Conduction and Insulation of Gauge Head and the insulation between the electrodes at the operating temperature shail be examined. (3) Magnetic Field of Magnet field at the pole centre or at the prescribed position shall be examined. (4) Vacuum Leakage of Gauge Head leakage test shall be performed us
38、ing a test gas. (5) Electrical Conditions of Controlled Measuring Unit tion, examination shall be made to confirm that the electrical conditions of the controlled measur- ing unit are the same as those at the time of calibration. The validity of conduction of the filament The direction of the magnet
39、ic field and the strength of the magnetic With the gauge head in operating condition, a vacuum With the gauge head in operating condi- 6.3 Calibration Vacuum gauges shall be calibrated according to the method specified in JIS Z 8750. 7. Indication of Measured Value Because the sensitivity of gauges
40、differs with the kind of gas, it shall be corrected where the kind and composition of the gas are known. Where the kind and composition of the gas are unknown, the pressure shall be indicated by the equivalent-nitrogen pressure. Remark: The method of correction where the kind and composition of the
41、gas are known is shown in formula (3). (3) S=$ xi . where, s : ionization gauge coefficient (Pa-) or sensitivity coefficient (A. pa-) S, : ionization gauge coefficient for nitrogen (Pa-) or sensitivity coefficient (A* pa-) xi : compositional ratio of individual component gas : specific sensity coeff
42、icient of individual component gas relative to nitrogen Reference: Generally gauges are preliminarily calibrated by using nitrogen. Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24
43、MSTNo reproduction or networking permitted without license from IHS -,-,- J I S Z*8752 89 4933608 0079784 b Z 8752-1989 Edition 1 Japanese Text Established by Minister of International Trade and Industry Date of Establishment: 1961-12-01 Date of Revision: 1989-03-01 Date of Public Notice i n Officia
44、l Gazette: 1989-03-03 Investigated by: Japanese Industrial Standards Committee Divisional Council on Basic Items This English translation is published by: Japanese Standards Association 1-24, Akasaka 4, Minato-ku, Tokyo 107 Japan O JSA, 1989 Printed in Tohyo by Hohbunsha Co., Ltd. Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/11/2007 00:22:24 MSTNo reproduction or networking permitted without license from IHS -,-,-