ECA 500-A-1989 Recommended Practice for Measurement of X-Radiation from Projection Cathode-Ray Tubes《投影式阴极射线管X辐射测量的推荐规程》.pdf

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1、I gEiEr ANSVEIA-500-A-1989 APPROVED: Fobruuy 2,1889 EIA STANDARD r I Recommended Practice for -.Measurement of X-Radiat ion 1 ?rom Proiection Cathode-Rav a EIA-500-A FEBCIUACIY 1968 ELECTRONIC INDUSTRIES ASSOCIATION ENGINEERING DEPARTMENT EIA 500-A 9 W 3234600 007L9L4 b NOTICE EIA Engineering Standa

2、rds and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his

3、 particular need. Existence of such Standards and Publications shall not in any respect preclude any member or non-member of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their volunta

4、ry use by those other than EIA members, whether the standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA d

5、oes not assume any liability to any patent owner, nor does it assume any obligation whatever to parties. adopting the Recommended Standard or Publication. This EIA standard is considered to have international standardization implication, but the International Electrotechnical Commission activity has

6、 not progressed to the point where a valid comparison between the EIA standard and the IEC document can be made. e This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to

7、 establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. Copyright 1989 Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 1722 Eye Street, N.W. Washington, D.C. 20006 PRICE: $10.00 All rights reserved Printed

8、in U.S.A. EIA 500-A 89 W 3234600 0071915 W EIA-500-A RECOMMENDED PRACTICE FOR MEASUREMENT OF X-RADIATION FROM PROJECTION CATHODE-RAY TUBES TABLE OF CONTENTS Paragraph 1.0 PURPOSE 1.1 Scope 2.0 APPARATUS 2.1 Search Instrument 2.2 Test Equipment 3. O CALIBRATION 4.0 TEST CONDITIONS Q 4.1 Tube Position

9、 4.2 External Components 4.3 Warm-up 4.4 Display 5.0 PROCEDURE 5.1 Hypothetical Cabinet 5.2 X-Radiation Measurements 6.0 REPORT FIGURE: FIGURE 1 Hypothetical Cabinet i Page 1 1 2 2 3 5 5 5 5 5 5 6 6 8 9 11 I- EIA 500-A 89 m 3234600 007LLb T m EIA-5 O O-A Page 1 RECOMMENDED PRACTICE FOR MEASUREMENT O

10、F X-RADIATION FROM PROJECTION CATHODE-RAY TUBES (From EIA Standards Proposal No. 2148, formulated under the cognizance of EIA JT-32 Committee on Electron Tube Safety.) 1.0 PURPOSE The purpose of this Standard is to obtain the x-radiation characteristics of projection cathode-ray tubes in order to pr

11、edict the levels emitted by tubes when the electrical characteristics of the application are known. 1.1 Scope This test method applies to the measurement of x-radiation emitted from projection cathode-ray tubes. For some applications the test procedures described in Recommended Standard EIA-503 IIRe

12、commended Practice for Measurement of X-Radiation from Direct-View Television Picture Tubes,“ may be more appropriately used than those described herein. CAUTION SAFETY CONSIDERATIONS Measuring instruments should be properly grounded. Caution should be taken to avoid shock hazard, particularly in th

13、e vicinity of the anode connection and the voltage metering system. Safety equipment should be worn at all times during the measurement procedure. X-ray film badges should be worn in accordance with established plant safety practices for monitoring radiation dosage. EIA SOO-A 87 M 3234b00 007L7L7 II

14、 = EIA-5 O O-A Page 2 2.0 APPARATUS 2.1 X-Radiation Detection Instruments 2.1.1 Search Instrument The location of maximum intensity (see paragraph 5.0) may be determined by the use of either of the following: a) A Rapid response instrument designed to detect low energy x-radiation. (Examples: G-M tu

15、be instruments such as the Texas Nuclear Model 2652; the Johnson TV X-1; or the Victoreen Model 491). Thin window ion chamber survey meters may also be used. See EIA Consumer Products Engineering Bulletin No. 3 ItMeasurement Instrumentation for X-Radiation from Television Receivers.Il b) X-Ray film

16、(on the surfaces of the hypothetical cabinet as shown in Figure 1.) (Examples of x-ray film - Kodak X-OMAT R Film, Code XR-2). 2.1.2 X-Radiation Measuring Instrument The principal x-radiation measuring instrument shall comply with the requirements of Title 21, Code of Federal Regulations (CFR), Chap

17、ter I, Subchapter J, Section 1020.10 I subparagraph (c) - (2) I and with EIA Consumer Products Engineering Bulletin No. 3 (CPEB-3). The instrument shall provide x-radiation measurements (mR/h) in the range of the applicable limit. The x-radiation sensitive volume shall have a cross section parallel

18、to the external surface of the hypothetical cabinet with an area of 10 cm2 and no dimension larger than 5 cm . EIA-5 O O-A Page 3 Measurements with instruments having other areas must be corrected for spatial non-uniformity of the x-radiation field to obtain the exposure rate averaged over a 10 cm2

19、area. X-radiation measurement data obtained with instruments having x-radiation sensitive volumes with cross section areas greater than 10 cm2 or dimensions larger than 5 cm, or both, need not be corrected for spatial non-unformities, unless data comparisons are to be made of data obtained from inst

20、ruments having different cross sectional areas. Measurement deviations due to instrument imprecision, energy dependence and other sources of error shall be commensurate with the current instrument art. Examples of instruments which fulfill these requirements are as follows: Victoreen Model 666 Fluor

21、oscopic Survey Meter complete with Background Probe Model 666-25 modified with a Mylar (Trademark, DuPont) window for operation in energy range of 6 kV to 80 kV. When the x-radiation level is less than 100 mR/h, the following measurement instrument may be used: Victoreen 440RF/C Radiation Exposure R

22、ate Measuring System 2.2 Test Equipment Stable electronic conditions must be provided for the operation of the tube under test and to measure anode voltage and current. 2.2.1 Anode Voltage Metering System The recommended anode voltage metering system incorporates a very stable and accurate high volt

23、age divider and voltmeter with an overall accuracy of & 0.1% and a digital readout using at least four significant figures, having a sensitivity of at least 0.01 kV. EIA SOO-A 9 3234600 0071919 5 EIA-5 O O -A Page 4 (The effect of the overall accelerating potential on the x-radiation characteristics

24、 is such that the x-radiation exposure rate could double for each 1 kV change of accelerator potential, thereby making accurate voltage measurement desirable.) If the recommended accuracy of the measurement system cannot be achieved, the inaccuracy shall be accounted for by reducing the recorded vol

25、tage reading by the maximum possible measurement deviation. 2.2.2 Anode Current Metering System The recommended anode current metering system incorporates an overall accuracy of & 1%. (The effect of the anode current on the x-radiation characteristics is that the x-radiation exposure rate is directl

26、y proportional to the anode current.) If the recommended accuracy of the anode current measurement system cannot be achieved, the inaccuracy shall be accounted for by reducing the recorded current reading by the maximum possible measurement deviation. 2.2.3 Power Supply for the Overall Accelerating

27、Potent ia 1 The recommended power supply for the overall accelerating potential incorporates a stability of & 0.05%. (The effect of the overall accelerating potential on the x-radiation characteristics is according as outlined in paragraph 2.2.1, thereby making a stable power supply desirable.) If t

28、he recommended stability of the power supply cannot be achieved, the variation shall be accounted for by recording the lowest voltage reading during a specific x-radiation measurement. 2.2.4 Deflection System X-Y raster generator and deflection system capable of driving the tube under test at rated

29、scan at approximately 30 frames per second and 500 or more lines. Nonlinearity of scan shall be within & 10% along each axis. I- 3.0 4.0 I EIA 500-A 89 323LlbOO 0073920 I = EIA-500-A Page 5 CALIBRATION 3.1 3.2 TEST 4.1 4.2 4.3 4.4 The x-radiation measuring instrument shall be calibrated by exposure

30、to a uniform x-ray field having an exposure rate and energy representative of those to be measured. The calibration shall be traceable to the National Institute of Standards and Technology. CONDITIONS Tube Position The tube under test shall be positioned relative to the test equipment so that measur

31、ements may be made as specified in paragraph 5.0. External Components External components normally mounted on the tube may be in -place while obtaining x-radiation characteristics. (External components may include deflection yokes, alignment coils, mounting hardware, implosion protection mechanisms,

32、 etc.) Warm-up A warm-up period shall be provided for both the tube and test equipment in order to obtain stable operating conditions before proceeding with the measurement. Anode current shall not vary or drift more than & 1% while measurements are being made. Display 4.4.1 Focus The tube under tes

33、t shall be operated at optimum focus. 4.4.2 Blanking The tube shall be operated with the dc voltages which result in an unblanked raster. EIA 500-A 89 m 3234600 007L92L 3 m EIA-5 O O-A Page 6 4.4.3 Multiple Guns Multiple gun tubes may be operated using only one gun. 4.4.4 Raster Geometry The horizon

34、tal and vertical scan controls shall be adjusted so that the raster width and height are within + 5% of the rated horizontal and vertical display dimensions. The major axis of the raster shall be parallel to the direction of the fast scan. The raster size shall be reported with the data. 5. O PROCED

35、URE The x-radiation exposure rate shall be measured as described below at the location of maximum intensity. The background radiation shall be verified at the test position and corrections applied to the observed data as required. 5.1 Hypothetical Cabinet X-radiation exposure rate measurements are t

36、o be made at the forward and rear sections of the hypothetical cabinet. The hypothetical cabinet is shown in Figure 1. Dimensions of the hypothetical cabinet are as follows : a) Length (L) = Published maximum overall length of the tube under test plus 27.5 cm b) The height and width (dimensions -H-

37、in Figure 1) of the hypothetical cabinet depend upon the maximum screen diameter or diagonal dimension. Dimension -H- of the hypothetical cabinet Maximum Screen Diameter or Diagonal of 15 cm 25 cm Dimension H 40 cm 50 cm Note Note: Maximum screen diameter or diagonal plus 25 cm. * EIA 500-A 89 M 323

38、4600 0073922 5 = 5.1.1 EIA-5 O O -A Page 7 As shown in Figure 1, the tube is centered within the hypothetical cabinet with the outermost surface of the faceplate of the tube positioned 20 cm back from the front of the hypothetical cabinet and with the position of the anode connector at 12 oclock. No

39、te: For rectangular tubes, the tube sides must be parallel to the sides of the hypothetical cabinet. 5.1.2 The forward section of the hypothetical cabinet is that portion of the cabinet that is in front of the outer-most front surface of the faceplate of the tube. The dimensions of the forward secti

40、on of the hypothetical cabinet are as follows: a) Length - 20 cm b) Height and Width - see paragraph 5.1 b). 5.1.3 The rear section of the hypothetical cabiet is that portion to the rear of the outer-most front surface of the faceplate of the tube. The dimensions of the rear section of the hypotheti

41、cal cabinet are as follows: a) Length - published maximum overall length of the tube plus 7.5 cm. b) Height and Width - see paragraph 5.1 b). For convenience in locating the x-radiation measuring instrument with respect to the hypothetical surfaces, a box, or parts of a box, of the size specified ma

42、y be constructed. The constructed box, or parts of the box, should be of a low absorbing material to prevent loss of measurement sensitivity. Unless the box is removed while measurements are being made, a correction factor must be determined EIA 500-A 89 = 323Yb00 0071923 7 EIA-500-A Page 8 over the

43、 voltage range used for each meter location on the box being used and the x-radiation data adjusted accordingly. 5.2 X-Radiation Measurements 5.2.1 The detector of the x-radiation measuring instrument shall be positioned outside of the hypothetical cabinet with the effective center of the detector 5

44、 cm from the surface of a hypothetical, nonabsorbing cabinet that is described in paragraph 5.1 and shown in Figure 1. The measuring instrument may be placed anywhere over the surfaces of the hypothetical cabinet described in paragraph 5.1, provided that the center of the detectors front face does n

45、ot overlap the outer edges of that surf ace of the hypothetical cabinet that is being measured. (When the plastic spacers of the Victoreen 440 RF/C survey meter are in contact with a surface, the distance from that surface to the effective center of the detector is 5 cm.) 5.2.2 5.2.3 The front surfa

46、ce of the detector shall be parallel to the surface of the hypothetical cabinet and positioned for maximum exposure rate. Forward Section of Hypothetical Cabinet 5.2.3.1 A measurement of x-radiation exposure rate shall. be made on the forward section of the hypothetical cabinet, the centerline of th

47、e detector is not to be positioned more than 20 cm from the front surface of the forward section of the hypothetical cabinet. See Figure 1 and Note*. EIA 500-A 89 W 3234600 0071924 9 W EIA-5 O O -A Page 9 5.2.3.2 A measurement of x-radiation exposure rate shall be made on the forward section of the

48、hypothetical cabinet at the location of the maximum exposure rate. *Note: If a measurement is made on the 20 cm sides of the forward section of the hypothetical cabinet, the centerline of the detector is to be positioned more than 20 cm from the front surface of the forward section of the hypothetic

49、al cabinet, see Figure 1. 5.2.4 Rear Section of Hypothetical Cabinet 5.2.4.1 A measurement of x-radiation shall be made on the rear section of the hypothetical cabinet at the location of maximum exposure rate. Note : When a measurement is made on the rear section of the hypothetical cabinet, the center-line of the detector shall not be positioned nearer than 20 cm to the front surface of the forward section of the hypothetical cabinet, see Figure 1. 5.2.5 One or more readings may be made at each measurement position. When more than one reading is made, the value reported shal