ECA-501-A-1990-R2001.pdf
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1、ANSI/EIA-501-A-1990 Approved: March 9,1990 Reaffirmed: February 28,2001 EIA STANDARD Recommended Practice for the Measurement of X-Radiation from Raster-Scanned Direct-View Data Display Cathode-Ray Tubes EIA-501-A (Revision of EM-501) MAY 1990 Electronic Components, Assemblies the TV X-I., or the Mo
2、del 49l,or equivalent. T h i n window ion chamber survey meters may also be used. See E L A Consumer Products Engineering Bulletin No. 3 “Measurement Instnunentation for X-Radiation fiom Television Receivers“.) 3 . 1 . 2 X-Radiation M e a s u r i n g Instrument The principal x-radiation measuring in
3、strument shall comply with the requirements of Title 21, Code o f Federal Regulations (CFR), Chapter I, Subchapter J, Section 1020.10, subparagraph (c)-(2), and with E I A Consumer Products Engineering Bulletin No3. The instrument shali provide x-radiation measurements (mRJh) or pA/Kg in the range o
4、f the applicable limit. The radiation volume shall have across-section parallel to the external surface of the hypothetical cabinet with an area of 10 cni! and no dimension larger than 5 cm. Measurement deviations due to instrument imprecision, energy dependence and other sources of error shall be c
5、ommensurate with the current instrument art. An example of an instrument which hilfills these requirements is the 440 RF/C, or equivalent. Measurements with instruments having other areas must be corrected for spatial non-uniformity of the radiation field to obtain the exposure rate averaged over a
6、1 O cni! area. NOTE: A larger area detector may be used, prowed that the field i s determined to be uniform over its aperture. Examples: 440 RF, 203A, and TV-150. 32 Test Equipment Stable electronic conditions must be provided for the operation of the tube under tbt and to measure anode voltage and
7、current. 32.1 Anode Voltage Metering System The recommended anode voltage divider and voltmeter with an overall accuracy of 2 0.1% and the digital readout using at least four significant tgures, having a sensitivity of at least 0.01 kV. me effect of the overall accelerating potential on the x-radiat
8、ion characteristics is such that the x-radiation exposure rate could double for each 1 kV change of accelerator potential, thereby making accurate voltage measurements desirable.) If the recommended accuracy of the measurement system cannot be achieved, the inaccuracy shall be accounted for by reduc
9、ing the recorded voltage reading b y the maximum possible measurement deviation. 32.2 Anode Current Metering System The recommended anode current metering system incorporates an overall accuracy of $I 1 % . (The effect o f the anode current on the x-radiation characteristics is that the x-radiation
10、exposure rate is directly 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. Copyright Electronic Com
11、ponents, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 00:20:54 MDTNo reproduction or networking permitted without license from IHS -,-,- EM-501-A Page 3 3.23 Power Supply for the Overall Acce
12、lerating Potential The recommended power supply for the overall acclerating potential incorporates a stabfiy of 0.05%. (The effect of the overall accelerating potential on the x-radiation characteristic iS according to paragraph 3.2.1, thereby making a stable power supply desirable.) If the recommen
13、ded shbility of the power supply cannot be achieved, the v a r i a t i o n shall be accounted for by recording the lowest voltage reading during a specific x-radiation measurement. 32.4 Anode Connector Assembly See paragraphs 6.2 and 63. 4. CALIBRATION 4.1 The measuring instrument shall be calibrate
14、d by exposure to a uniform x-ray field having an exposure rate and energy representative of those to be measured. 4.2 The calibration shall be traceable to the National Institute of Standards and Technology (NIST). 5. TEST CONDITIONS 5 . 1 Tube Position The tube under test shall be positioned relati
15、ve to the test equipment so that measurements may be made as specified in paragraph 6.0. 5 2 Extemg Components Ehternal components normaiiy mounted on the tube may be in place while obtainiag x-radiation characteristics. (Extemai components may indude deflection yokes, alignment coils, mounting hard
16、ware, implosion protection mechanisms, etc.) 53 warm-up A warm-up period shali be provided for both the tube and test equipment in order to obtain stable operating conditions before proceeding w i t h the measurement. Anode current shall not vary or drift more than $L 1% while measurements are b e i
17、 made. 5.4 Display 5.4.1 Focus The tube under test shd be operated at optimum focus. 5.4.2 Blanking The tube shall be operated with dc voltage which result in an unb1anke-d raster. 5.4.3 Multiple Guns Multiple gun tubes may be operated using only one gun. . Copyright Electronic Components, Assemblie
18、s & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 00:20:54 MDTNo reproduction or networking permitted without license from IHS -,-,- EIA-501-A Page 4 5.4.4 Raster Geometry The horizontal and vertid scan co
19、ntrols shall be adjusted so that the raster width and height are 90% of the screen width and height. The linearity of the scan shaii be checked and adjusted with a crosshatch pattern such that the &tance between crosshatch lines measured along the major and minor axes shaU be witbiu 10% of the corre
20、sponding measurements at the center of the screen. The radius o f mature of a l i four raster sides shd not be less than 200 un. 6. PROCEDURE The x-radiation exposure rate shaU be m e a s u r e d as described below at the location of maximum intensity. The background radiation shall be verified at t
21、he test position and corrections applied to the observed data as required. 6.1 Radiation from the Tube Face The radiation fiom the tube face shall be measured with the effective center of the detector 5 cm fiom the surface of the tube. NOTE: When the plastic spacers on the 4 4 0 RF/C Survey Meter, o
22、r equivalent, are in contact with the tube face or the surface of the hypothetical cabmet, the distance from the surface to the effective center of the detector is 5 cm. The measured area of the tube face must be extended past the extremities o f the actual faceplate to completely enclose the effect
23、ive volume of the hypothetid cabinet described in paragraph 6.4. This extension of the tube face is achieved by hypothetidy extending the major spherical curvature o f the front face o f the tube to the top, bottom and side surfaces of the hypothetical cabmet. The measuring instrument may be placed
24、anywhere over the tube face or over the hypothetid extension of it, provided that the center of the detectors front face does not overlap the top, bottom or sides of the hypothetical cabmet. 6.2 Radiation Emitted from the Funnel Portion Radiation emitted Erom the funnel portion of the entire tube (&
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