a 
Forward and Backward Currents of 1N21 Silicon Rectifiers under Reactor Irradiation* 
Bomac Microwave Sylvania Kentron 
Reac- Unit 1 Unit 2 Unit 3 Unit 4 Unit 6 Unit 6 Unit 7 Unit 8 
Date tor Integrated 
and upor thermal flux F B F B F B F B F B PF B F B PF B 
time down (10!7 n/cm?) (ma) (ua) (ma) (ua) (ma) (ua) (ma) (ua) (ma) (wa) (ma) (ua) (ma) (ua) (ma) (ua) 
1/3/56 
9:45 d 0. 42 120 «632 «6115 «#38 400 38 200 16 2,200 39 13 44 86 32 210 
10:30 u 0.014 44 105 35 107 38 380 37 200 19 2,300 40 14 44 21.5 32 180 
10:45 d 0.019 17 390 35 110 38 540 37 165 19 2,600 40 18.5 44 20.5 32 380 
11:30 d 0.036 15.5 390 33 110 40 415 38 175 205 3,000 40 18 45 23.5 32 360 
12:30 d 0.045 17.7 380 37 105 39 600 38 175 23 3,300 40 16.3 45 21.5 33 360 
1:30 u 0.061 12 380 36 140 38 500 37 200 26 3,700 40 21 45 27 33 390 
2:50 u 0.090 17.5 300 36 135 39 600 38 170 26 4,800 40 26 46 30 33 390 
3:45 d 0.120 17.5 610 37 140 40 590 38 180 29 4,700 38 25 135 26 27 380 
1/4/56 
8:40 u 0.416 17.5 610 35 137 37 875 38 197 31 9,000 33 215 125 34 400 eal 
10:15 u 0.450 14 975 38 137 33 620 24 290 35 8,000 35 8,500 125 40,000 450,000 400,000 
11:25 u 0.475 14 7,800 38 140 37 620 38 300 28 5,800 38 7,400 125 45,000 480,000 480,000 
2:00 u 0.531 ns 38 340 39 620 39 300 =e « co sabe 
3:00 u 0.552 36 310 38 620 38 295 
4:00 u 0.574 35 300 37 600 37 295 
1/5/56 
8:40 d 0.868 35 280 36 560 37 250 
10:00 u 0.872 31 280 32 660 33 320 
11:00 u 0.893 30 290 31 560 32 260 
12:00 u 0.915 32 280 32 640 32 240 
1:00 u 0.936 33 290 36 660 37 235 
2:00 u 0.958 35 300 37 580 37 = ©6280 
3:00 u 0.980 36 300 37 660 38 280 
4:00 d 1.001 36 300 37 590 38 230 
* 1 volt applied for both forward and backward currents. 
** At backward current > 5 ma, rectifier was considered destroyed. 
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FIG. 8. Curves of emission current vs 
integral thermal flux demonstrate failure 
of 5R4WGB tubes. At failure, plate 
current decreased with either increase 
or decrease of plate voltage from 30 
volts d-c. Points represent averages 
for 6 tubes 
ation to 10!8 n/cm? with little or no 
apparent damage. Some examples are 
cathode-ray tubes 3JP1, 3JP7, and 
3JP12; gaseous voltage regulators 
OA2WA, 0B2WA, and 5651; pentagrid 
converter 6BE6; twin diodes 6AL5 and 
6080; and subminiature types 5718, 
5896, and 6C4. 
Other tubes failed rapidly. Exam- 
ples are a beam-power 829-B, which 
failed before 10!7 n/em?; orthicons and 
vidicons, which suffered glass damage 
below 1017 n/em?; rectifiers 5R4WGB, 
four of six failing before 4 X 10!7 n/em?. 
Figure 8 shows the behavior of the 
5R4WGB rectifiers before failure. 
Metal-enclosed tubes are under test. 
The radiation resistance of a given 
component type varies widely from 
manufacturer to manufacturer, and 
there is hope that only minor changes 
in materials and design will greatly im- 
prove many components. Tests on 
resistors, semiconductor devices, and 
vacuum tubes support this view. 
The gas problem in vacuum tubes 
can be solved by studying seals and 
glasses. Some of the tubes that failed 
most rapidly contained boron in the 
glass. 
It is unfortunate that most compo- 
nent manufacturers regard their formu- 
las as private data, and it is difficult to 
determine what materials and processes 
cause trouble. 
* * * 
The data quoted above resulted from the 
efforts of the radiation-effects group of Admiral 
Corporation; program director is E. R. Pfaff. 
BIBLIOGRAPHY 
1. E. R. Pfaff, R. D. Shelton, The effects of 
nuclear radiation on electronic components. 
Admiral Corporation (1955, '56) 
2. Nucueonics 14, No. 7, 33 (1956) 
3. C. C. Robinson, American Aviation, 19, No. 
26, 53 (1956) 
4. A. E. Javitz, Electrical Manufacturing, 55, 
No. 6, 85 (1955) 
6. Effects of radiation on dielectric materials, 
ONR Symposium Report ACR-2. (De- 
cember, 1954) 
6. O. Sisman, C. Bopp, Physical properties of 
irradiated plastics. ORNL-928 
7. R. D. Shelton, The problem of electronic com- 
ponents in nuclear power plants, Aeronautical 
Electronics Conference Proceedings, Dayton, 
Ohio (1956) 
8. A. Thomas, Nucteonics 13, No. 11, 129 
(1955) 
9. J. R. Milliron, Electrical Manufacturing 56, 
No. 5, 125 (1955) 
H. Thanos, R. Weber, Investigation of solar 
cells. Admiral Report (August 5, 1955) 
Bell Telephone Laboratories advertisement, 
Electronics 29, No. 1, 78 (1956) 
10. 
11. 
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