1、INCH-POUND MIL-PRF-1/1388G 11 September 2013 SUPERSEDING MIL-PRF-1/1388F 15 August 2012 PERFORMANCE SPECIFICATION SHEET ELECTRON TUBE, RADIATION COUNTER TYPE 7840 This specification is approved for use by all Departments and Agencies of the Department of Defense. The requirements for acquiring the e
2、lectron tube described herein shall consist of this document and the latest issue of MIL-PRF-1. DESCRIPTION: Thin end mica window, self-quenched counter tube for detection of low intensity beta radiation. See figure 1. Mounting position: Any. Weight: 7 ounces (198.5 grams) nominal. ABSOLUTE RATINGS:
3、 Parameter: Ebb TA Rp Mica window thickness Unit: V dc C Meg mg/cm2 Maximum: 1,600 40 - 2.2 Minimum: 1,300 0 1 1.8 Test conditions: 1,400 - 1 - See footnotes at end of table I. _ GENERAL: Qualification - Required. Holding period (MIL-STD-1311) - 60 days. Window test - 13/ Shelf life - Required (see
4、conformance inspection, part 1). Acceptance test - Required. 15/ Service-life guarantee (MIL-PRF-1) - With qualifying activity approval manufacturer may provide service-life guarantee, in lieu of life test. Guaranteed tube operating time shall be 250 hours minimum. Marking - Tubes sold under service
5、-life guarantee shall be marked with contract number and with the number of tube operating hours (250 hrs min) guaranteed. This specification sheet uses accept on zero defect sampling in accordance with MIL-PRF-1, table III. AMSC N/A FSC 5960 Provided by IHSNot for ResaleNo reproduction or networkin
6、g permitted without license from IHS-,-,-MIL-PRF-1/1388G 2 TABLE I. Testing and inspection. Inspection Method Notes Conditions Symbol Limits Unit MIL-STD-1311 Min Max Conformance inspection, part 1 Background, contamination and photosensitivity 6201 2/ 6/ 12/ 17/ t = 4 minutes (min) N/t - 20 Npm Sta
7、rting voltage 6211 5/ 12/ 18/ 19/ Pulse amplitude = 0.50 V; Nps = 100 (min); R2 = 1 Meg 10%; R1 = C1 = C2 = 0; C3 = 0.01 F 10% Es - 1,250 V dc End-of-plateau voltage 6216 - Ps = 3%/100 V dc Ee 1,650 - V dc Relative plateau slope 6216 15/ Voltage range = 1,300 to 1,600 V dc Ps - 3 %/100 V dc Backgrou
8、nd, contamination and photosensitivity 6201 2/ 6/ 12/ 17/ t = 4 minutes (min) N/t - 20 Npm Response count rate and current (beta) 6221 3/ 6/ 12/ Ebb = 1,400 V dc; counting time = 2 minutes (min) N/t 3/ - Npm Shelf life - 14/ - - - - Conformance inspection, part 2 Leakage current 6205 - Ebb = 700 Lib
9、 - 0.5 A dc Shock 1041 1/ 11/ 20/ 450 G - - - - Response count rate and current (hysteresis (1a) 6221 6/ 7/ 8/ Ebb = 1,400 V dc; t = 2 minutes (min); record count rate values - - - - Response count rate and current (hysteresis (1b) 6221 6/ 8/ Ebb = 1,400 V dc; t = 15 minutes (min) - - - - Response c
10、ount rate and current (hysteresis (1c) 6221 6/ 8/ Ebb = 1,400 V dc; t = 2 minutes (min); from reading taken from count rate (1a) N/t - 20 % Response count rate and current (gamma) 6221 6/ 9/ 12/ Ebb = 1,400 V dc; counting time = 2 minutes (min) N/t - 110 Npm See footnotes at end of table. Provided b
11、y IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1388G 3 TABLE I. Testing and inspection - Continued. Inspection Method Notes Conditions Symbol Limits Unit MIL-STD-1311 Min Max Conformance inspection, part 3 Life test - Group D; Ebb = 1,400 V dc; N/t
12、= 1,000 Npm; t = 250 hours - - - - Life-test end points: Response count rate and current (beta) Response count rate and current (gamma) - 6221 6221 - - N/t N/t - - 10 10 % % Variable-frequency vibration 1031 1/ 10/ 20/ Ebb = 0 - - - - Temperature range, operating 1026 4/ N/t - 20 % Packaging - 16/ -
13、 - - - 1/ Criterion for passing this test shall be compliance after test of at least 80 percent of the tubes with the requirements for the following: (a) Starting voltage. (b) End-of-plateau voltage. (c) Relative plateau slope. (d) Response count rate and current (beta). (e) Response count rate and
14、current (gamma). 2/ The tube shall be exposed to radiation from a General Electric 4-watt germicidal lamp, Type G-4T4/1, or equivalent, with relative positions as shown on figure 2. 3/ The counting rate shall not vary by more than 0.10 N/t from the value (approximately 10,000 counts per minute (cpm)
15、 marked on the Standard Beta Reference Source (SBRS). The SBRS shall be mounted in recess of the sample positioning shelf specified with the SBRS. The proper position of this shelf for this test is specified with the SBRS. 4/ With the tube in a field giving 10,000 100 Npm at 1,400 V dc, tube respons
16、e (count rate) shall be determined at 1,300, 1,400, and 1,600 V dc at each of the following temperatures and in the order shown. (a) Room temperature. (b) 5C. (c) Room temperature. (d) 40C. (e) Room temperature. Provided by IHSNot for ResaleNo reproduction or networking permitted without license fro
17、m IHS-,-,-MIL-PRF-1/1388G 4 TABLE I. Testing and inspection - Continued. 5/ After the holding period, starting voltage shall not vary by more than 7 volts. 6/ The tube shall be mounted vertically in the lead shield (see figure 3) of the excitation unit. 7/ The tube shall have been inoperative for a
18、24-hour period prior to test. 8/ Beta reference source shall be in position as specified in 3/. 9/ Test shall be performed with the assembly shown on figure 3 in a 1.4 mr/hr Cobalt-60 radiation field (calculated). 10/ The tube shall be tested only with its longitudinal axis vertical and parallel to
19、the direction of motion. The tube shall be mounted by means of a rigid clamp at the base of the tube. 11/ The tube shall be tested only with its longitudinal axis horizontal and parallel to the direction of motion of the hammer. The tube shall be mounted by means of a rigid clamp at the base of the
20、tube. 12/ This test shall be performed at the conclusion of the holding period. 13/ All tube windows shall be tested to assure that they can withstand an internal pressure of half of an atmosphere less than ambient pressure. 14/ The shelf life requirements shall be as follows: (a) Tubes tested and a
21、cquired in accordance with this document shall be capable of a shelf life for a period of 18 months after the date of shipment from the manufacturers plant. At any time during this shelf life period the tubes shall be capable of meeting all requirements of conformance inspection, part 1, as specifie
22、d herein. Tubes found to be defective within the shelf life period shall be replaced by the manufacturer at no cost to the Government. (b) A shelf life of 90 days with the conformance inspection, part 1, starting voltage test shall be instituted during continuous production, but shipments of that mo
23、nths production shall not be held pending completion of the test. Tubes shall be considered to conform to this document when three of the four tubes for each of the first 3 months production and 75 percent of the cumulative quantity pass the test. If either of the above conditions are not satisfied,
24、 shipments shall be halted until three or four tubes of current production conform to the starting voltage test. 15/ The relative plateau slope requirements shall be with the discrimination level of the scaler set at 0.25 V 10 percent for standard Geiger-Mueller counter tube operation, and accomplis
25、hed in accordance with the following steps: (a) With the equipment in operation and prepared for counting, set the high voltage adjust control to obtain 1,400 V dc. (b) Mount standard reference source SBRS on the sample positioning shelf, place the shelf in position 1 of the tube, mount assembly and
26、 count for 5 minutes at 1,400 V dc. A new Geiger-Mueller counter tube (one that has not been used for a month or more) should be counted for 15 minutes rather than 5 minutes. It is not necessary to record the count rate obtained in this step. (c) If the background is unknown, remove SBRS and obtain
27、and record a 20 minute background count rate (cpm). (d) Place SBRS on the sample positioning shelf; place shelf in position 1 of the tube mount assembly. CAUTION If at any time while performing steps 16e through 16g it becomes apparent that the tube under test is in continuous discharge (rapidly inc
28、reasing count rate for a constant value of applied voltage), immediately set high voltage adjust control to 1,200 V dc. Determine if tube damage has occurred by raising the voltage in 50 V dc increments every 5 minutes. Do not exceed a high voltage setting of 1,500 V dc at any time. Otherwise contin
29、uous discharge will damage the tube. If continuous discharge occurs, again, replace tube. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1388G 5 TABLE I. Testing and inspection - Continued. (e) Count SBRS for 100,000 counts minimum in the
30、same position at 1,300 V dc and determine and record count rate in counts per minute (cpm). Count rate N1 equals total count divided by counting time in minutes minus background. (f) Count SBRS for 33,333 counts minimum in the same position at 1,400 V dc and determine and record count rate in counts
31、 per minute. Count rate N2 equals total count divided by counting time in minutes minus background. (g) Count SBRS for 100,000 counts minimum in the same position at 1,500 V dc and determine and record count rate in counts per minute. Count rate N3 equals total count divided by counting time in minu
32、tes minus background. (h) Determine plateau slope in percent as follows: Percent per 100 V dc slope equals 100 times (N3 minus N1) divided by the quantity (N3 plus N1). This result shall be less than or equal to 3 percent per 100 V dc. (i) The measured count rate N2 shall be within 10 percent of the
33、 quantity, (N1 plus N3) divided by 2. 16/ Each tube shall be packaged in a container capable of withstanding pressures in the range of 87.3 to .760 mmHg. 17/ Spurious pulses of amplitude greater than four volts shall not occur after four minutes of operation. 18/ A new Geiger-Mueller tube (one that
34、has not been used for a month or more) should be counted at 1,400 V with standard reference source SBRS on shelf in position 1 of the tube-mount assembly for 15 minutes before starting voltage is measured. 19/ Starting voltage test circuit: 20/ The manufacturer, with the approval of the qualifying a
35、ctivity, may perform this test on a periodic basis, versus performing the test on every lot. Approval will be based on demonstrating to the qualifying activity the capability of the design to meet this requirement. If the design, material construction or processing of the tube is changed or if there
36、 are any quality problems, the qualifying activity may require resumption of the original testing frequency. This allowance does not relieve the manufacturer from meeting the test requirements in case of dispute. Provided by IHSNot for ResaleNo reproduction or networking permitted without license fr
37、om IHS-,-,-MIL-PRF-1/1388G 6 NOTE: Reference dimension C is the effective mica window diameter. FIGURE 1. Outline drawing of electron tube types 7840. Dimensions Ltr Inches Millimeters Min Max Min Max Conformance inspection, part 2 A - 4.50 - 114.3 B 1.367 1.385 34.72 35.18 D 2.610 2.640 66.29 67.06
38、 Conformance inspection, part 3 (see note) F Base: A4-9 (EIA) Reference dimensions C 1.125 28.58 E .031 0.79 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1388G 7 FIGURE 2. Position of tube for photosensitivity test FIGURE 3. Tube positio
39、n and shielding for response tests. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1388G 8 Referenced documents. In addition to MIL-PRF-1, this specification sheet references MIL-STD-1311. The margins of this specification are marked with
40、vertical lines to indicate where changes from the previous issue were made. This was done as a convenience only and the Government assumes no liability whatsoever for any inaccuracies in these notations. Bidders and contractors are cautioned to evaluate the requirements of this document based on the
41、 entire content irrespective of the marginal notations and relationship to the last previous issue. Custodian: Preparing activity: Navy - EC DLA - CC Air Force - 85 DLA - CC (Project 5960-2013-051) Review activities: Navy - AS, MC, OS Air Force - 99 NOTE: The activities listed above were interested
42、in this document as of the date of this document. Since organizations and responsibilities can change, you should verify the currency of the information above using the ASSIST Online database at https:/assist.dla.mil/. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
