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1、Electronic Industries Alliance 2500 Wilson Boulevard. Arlington. Virginia 22201 -3834 703-907-7500 fax 703-907-7501 www.eia.org March 6, 2001 ERRATA TO: Recipients of the February 2001 Reaffirmed ANWEIA-503-A “Recommended Practice for the Measurement of X-Radiation from Direct-View Television Pictur
2、e Tubes“ NOTE: Please replace pages 5 and 6 with the pages attached. Part of the text on page 6, Section 6.5.1 did not print after converting from Word Perfect to Word format when the document was reaffirmed. We are sorry for any inconvenience this may have caused. Sincerely, Phil. CdtofJ Publicatio
3、ns Office Technology Strategy the TV X-1; or the Model 491. Thin window ion chamber survey meter may also be used. See EL4 Consumer Products Engineering Bulletin No. 3 “Measurement Instrumentation for X-Radiation from Television Receivers“. 3.1.2 X-Radiation Measuring Instrument The principal x-radi
4、ation measuring instrument shall comply with the requirements of Title 21, Code of Federal Regulations (CFR), Chapter I, Subchapter J, Section 1020.10, subparagraph (c)-(2), and with EL4 Consumer Products Engineering Bulletin No. 3. The instrument shall provide x-radiation measurements (mR/h) in the
5、 range of the applicable limit. The x-radiation sensitive volume shall have a cross-section parallel to the external surface of the hypothetical cabinet of 10 CII? and no dimension larger than 5 cm. Measurement deviations due to instrument imprecision, energy dependence and other sources of error s
6、h d be commensurate with the current instrument art. An example of an instrument that fulfills these requirements is the 440 RF/C. Measurement with instruments having other areas must be corrected for spatial non-uniformity of the radiation field to obtain the exposure rate averaged over a 1 0 cm2 a
7、rea. NOTE: A larger area detector may be used, provided that the field is determined to be uniform over its aperture. Examples: 440 RF, A and TV-150. 3.2 Test Equipment Stabie electronic conditions must be provided for the operation of the tube under test and to measure anode voltage and current. 3.
8、2.1 Anode Voltage Metering System The recommended anode voltage metering system incorporates a very stable and accurate high voltage divider and voltmeter w i t h an overail accuracy of 0.1% and a digital readout using at least four signifcant figures, having a sensitivity of at least 0.01 kV. (The
9、effect of the overall accelerating potential on the x-radiation characteristics is such that the x-radiation exposure rate could double for each 1 kV change of accelerator potentia thereby making accurate voltage measurements desirable.) If the recommended accuracy of the measurement system cannot b
10、e achieved, the inaccuracy shall be accounted for by reducing the recorded voltage reading by the maximum possible measurement deviation. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie No
11、t for Resale, 03/30/2007 00:15:25 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A 503-A S O - 3234600 0073968 7 ! 5.1 Tube Position 4 I 5.2 External Components Q I 5 . 3 Warm-up EIA-503-A Page 3 3 . 2 . 2 Anode Current Metering System The recommended current metering
12、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 directly proportional to the anode current.) if the recommended accuracy of the anode current measurement system cannot be achieved, the inacc
13、uracy shall be accounted for by reducing the recorded current reading by the maximum possible measurement deviation. Power Supply for the Overall Accelerating Potential The recommended power supply for the overall accelerating potential incorporates a stabaty of 0.05%. (The effects of the overall ac
14、celerating potential on the x-radiation characteristics i s i n accordance with paragraph 3.2.1, thereby making a stable power supply desirable.) If the recommended stability of the power supply cannot be achieved, the variation shall be accounted for by recording the lowest voltage reading during a
15、 specific x-radiation measurement. 3 . 2 . 3 3 . 2 . 4 Anode Connector Assembly See paragraphs 6.2 and 6.3. 4 . CALIBRATION 4 . 1 The measuring instrument shall be calibrated by exposure to a uniform x-ray field having an exposure rate and energy representative of those to be measured. 4.2 The calib
16、ration shall be traceable to the National Institute of Standards and Technology (NIST). 5. TEST CONDITIONS The tube under test shall be positioned relative to the test equipment so that measurements may be made as specified in paragraph 6.0. External components normally mounted on the tube may be in
17、 place while obtaining x-radiation characteristics. (External components may include deflection yokes, aiignment c o i l s , mounting hardware, implosion protection mechanisms, etc.) A warm-up period shall be provided for both the tube and test equipment in order to obtain stable operating condition
18、s before proceeding with the measurement. Anode current shali not vary or drift more than & 1% while measurements are being made. 5.4 Display 5 . 4 . 1 Focus The tube under test s h d be operated at optimum focus. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS un
19、der license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 00:15:25 MDTNo reproduction or networking permitted without license from IHS -,-,- EIA 503-A 90 3234b00 007L9b9 9 EIA-503-A Page 4 5.4.2 Blanking The tube shall be operated with dc voltages which res
20、ult in an unblanked raster. 5 . 4 . 3 Multiple Guns Multiple gun tubes may be operated using only one gun. 5.4.4 Raster Geometry The horizontal and vertical scan controls shall be adjusted so that the raster width and height coincide with the screen width and height. The linearity of the scan shall
21、be checked and adjusted with a crosshatch pattern such that the distance between crosshatch lines measured along the major and minor axes shall be within +. 10% of the corresponding measurements at the center of the screen. The radius of curvature of all four ( 4 ) raster sides shall not be less tha
22、n 200 cm. The horizontal and vertical raster dimensions shall then be increased by 10% while maintaining the established linearity. 6 . PROCEDURE 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
23、 test position and corrections applied to the observed data as required. 6 . 1 Radiation from the Tube Face The radiation from the tube face shall be measured with the effective center of the detector 5 cm from the surface of the tube. NOTE: When the plastic spacers on the 440 RF/C Survey Meter are
24、in contact with the tube face or the surface of the hypothetical cabinet, 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 of the actual faceplate to completely enclose the effective volume of the
25、hypothetical cabinet described in paragraph 6 . 4 . This extension of the tube face is achieved by hypothetically extending the major spherical curvature of the front face of the tube to the top, bottom and side surface of the hypothetical cabinet. The measuring instrument may be placed anywhere ove
26、r the tube face or over the hypothetical extension of it, provided that the center of the detectors front face does not overlap the top, bottom or sides of the hypothetical cabinet. 6 . 2 Radiation Emitted from the Funnel Portion of the Entire Tube (Exclusive of the Anode Contact and Tube Face) Radi
27、ation emitted from the funnel portion of the entire tube (exclusive of the anode contact and tube face) shall be measured with the effective center of the detector 5 cm from the surface of the hypothetical, non-absorbing cabinet that is described in paragraph 6 . 4 and shown in Figure 2. The measuri
28、ng instrument shall be positioned for maximum exposure rate with the front face of the detector parallel to the surface of the cabinet. The measuring instrument may be placed anywhere over the surfaces of the hypothetical cabinet described in paragraph 6 . 4 , provided that the center of the detecto
29、rs front face does not overlap the outer edges of that surface of the hypothetical cabinet that is being measured. The anode contact shall be covered with a 2.5 cm diameter attenuating shield having a minimum absorption equivalent to 0 . 2 5 mm of lead and shall be concentric with the anode contact,
30、 as shown in Figure 3. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 00:15:25 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A 5
31、03-A 90 W 3234b00 0073970 5 W EIA-503-A Page 5 6.2.1 Neck Radiation High voltage breakdown may occur at the electron gun under the stress of extremely high anode voltage. The resultant arcing or leakage, or both, may cause spurious x-radiation, which is independent of beam current, to emanate throug
32、h the glass neck of the picture tube. When making measurements at anode voltage above the maximum rating of the tube, and it is desired to determine the exposure rate resulting from the beam current only, the x-radiation from the neck of the tube should be shielded from the survey meter. 6.3 Radiati
33、on Emitted Through the Anode Contact Radiation emitted through the anode contact shall be measured with the effective center of the detector 5 cm from the surface of the hypothetical cabinet. (a) Electrical connection to the anode contact shall be made with a non-attenuating wire connector shown in
34、Figure 1, and ) all of the glass surface of the anode contact side of the funnel portion (including the frit seal area) shall be covered with an apertured shield of 6 mm maximum thickness, spaced a maximum of 3 mm from the funnel surface at the anode contact. A 2.5 cm diameter hole in the shield is
35、centered around the anode contact. The minimum x-ray absorption of the shield shall be equivalent to at least 0.25 mm of lead. 6.4 Hypothetical Cabinet The hypothetical cabinet is shown in Figure 2, the sides of the hypothetical cabmet shall be 2.5 cm from the outside surface of the tube (excluding
36、the extra thickness of any applied safety system, such as the tension band) at the ends of the major and minor axes of the face. The back shall be formed in part by a vertical circular surface of 8.5 cm diameter concentric with the axis through the neck of the tube. . This circular surface is to be
37、located 2.5 cm behind the published maximum protrusion of the base of the tube, which is to be measured relative to the center of the front face of the tube. The rear circular surface of the hypothetical cabinet is then at a fixed distance behind the front face of the tube (for any given tube type),
38、 the actual distance being the maximum published overall length of the tube plus 2.5 cm. From the outer circumference of this circular surface, a concenttic conical surface is to extend forward at 4 9 to the tube axis until the diameter of the conical section is increased to 28.5 cm. A vertical plan
39、e is then constructed radiating out from this maximum diameter of the cone, to form the remainder of the back of the cabinet as shown in Figure 2A. Exceptions: The conical section will be completely removed for all tube sizes with a minimum registered screen diagonal of less than 2 1 . 5 cm, and the
40、 back of the cabinet wiil be a flat vertical surface located 2.5 cm behind the published maximum protrusion of the base of the tube as shown in Figure 2C. For all other sizes, where the resultant cabinet height is less than 28.5 cm, the maximum diameter of the conical section coincides with the maxi
41、mum height of the cabinet. The vertical plane forming the remainder of the back of the cabinet is then constructed radiating from the maximum diameter of this shortened conical section as shown in Figure 2B. For convenience in locating the x-radiation search and measuring instruments with respect to
42、 the hypothetical surfaces, a box, or parts of a box, of the size specified may be constructed. However, while measurements are made in the vicinity of the maximum diameter of the conical section of the back of the cabinet, either the flat surface radiating from the maximum diameter of the cone, or
43、the conical section will have to be removed to allow the x-radiation measuring instrument to be placed on any part of that surface without hindrance from the 0 - _ _ other parts of the box. O Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA L
44、icensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 00:15:25 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A 503-A 90 3234600 0073973 7 EIA-503-A Page 6 The constructed box, or parts of the box, should be of a low absorbing material to preve
45、nt loss of measurement sensitivity. Unless the box is removed while measurements are being made, a correction factor must be determined over the voltage range used for each meter location on the box being used and the x-radiation data adjusted accordingly. 6.5 Reading Technique 6.5.1 Model 440 RF/C
46、- it is recommended that the 0-1 scale not be used. The measurement period should not be less than 30 seconds. The lowest reading during the measurement period should be recorded, ignoring sporadic downscale pulses. Background should be determined using the same technique. 6.5.2 During the test expo
47、sure period, the anode voltage and current shali be constantly monitored and the lowest observed values of each recorded. 7. REPORT 7.1 Origin - Date - Observers Name - Laboratory - Procedure Used 7.2 Tube Identification External shielding and components, including deflection yokes, if used, shall b
48、e specified together with their critical dimensions and their location on the tube. 7.3 The foilowing equipment information shd be on record: - Manufacturer - Serial Number - Accuracy Specification - Correction Factors, if applicable - Calibration Date - Calibration Source and Accuracy - Any other p
49、ertinent information to qualify the results. The foilowing information is required for at least: - The anode voltage metering source. - The anode current metering source. - The principal x-radiation measuring instrument. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 0