First results from from
the test with neutrons at the PROSPERO 30.9 1998
Contents: 1) Temperature
measurements during the test
2) Reference resistor measurments during the test
3) Test of optocouplers (non- powered)
4) Test of microcontrollers (non-powered)
Last Updated on 16/11/98
1) Temperature tests
The temperature at the experimental area as measured by the LMB. The probe
Pt4 was moved to the heatsink of the CCDs tested by Harry van der Graaf
of Nikhef. The irradiations started 9:41 and stopped 10:22 for the first
period. with about 2 1011 neutrons/cm2 reached
at a distance of 3m. A second period started after 11:40 and full
intensity was reached 12:00. The readout of the LMB analog part stopped
at 12:07, while the CAN controller was working at the end of the test 15:10.
The tests show that communication with the analog part could stand a total
does rate of 31011 while the digital CAN controller was still
working for a total dose rate of about 91012 neutrons/cm2
Figure 1 The temperature measured during the Prospero test.
2) Measurements of the reference resistor during the tests.
Figure 2 The change in the 3 reference resistors has measured by the
LMB during the PROSPERO tests.
Tests of optocouplers
29 optocouplers were measured and divided into 3 lots with the same Current
Transfer Ratio in average.
The lots were subject to different levels irradiations. The results
are shown in the Table below and in the Figure 3.
| |
|
|
|
Dose in n/cm2 (equiv 1MeV) |
| |
Initial
CTR (%) |
|
|
21011 |
71011 |
91012 |
| Component |
lot
1 |
lot 2 |
lot 3 |
lot
1 |
lot
2 |
lot
3 |
| PP1 |
163.6 |
|
|
94.8 |
|
|
| PP2 |
|
155.8 |
|
|
32.1 |
|
| PP3 |
|
|
163.9 |
|
|
0.9 |
| PP4 |
153.8 |
|
|
88.7 |
|
|
| PP5 |
|
153.9 |
|
|
32.5 |
|
| PP6 |
140.9 |
|
|
74.8 |
|
|
| PP7 |
168.9 |
|
|
88.8 |
|
|
| PP8 |
|
|
166.4 |
|
|
0.9 |
| PP9 |
155.4 |
|
|
78.8 |
|
|
| PP10 |
170.4 |
|
|
93.6 |
|
|
| PP11 |
|
168.8 |
|
|
34.0 |
|
| PP12 |
|
|
161.6 |
|
|
0.9 |
| PP13 |
156.9 |
|
|
87.6 |
|
|
| PP14 |
|
|
126.4 |
|
|
|
| PP15 |
|
149.9 |
|
|
29.6 |
|
| PP16 |
|
158.5 |
|
|
36.1 |
|
| PP17 |
|
|
171.5 |
|
|
1.0 |
| PP18 |
|
148.6 |
|
|
43.5 |
|
| PP19 |
|
156.3 |
|
|
41.0 |
|
| PP20 |
|
|
138.6 |
|
|
0.9 |
| PP21 |
155.5 |
|
|
83.0 |
|
|
| PP22 |
|
|
|
|
|
|
| PP23 |
|
|
165.2 |
|
|
0.9 |
| PP24 CTR=154.2(ref) |
|
|
|
|
|
|
| PP25 |
|
|
157.9 |
|
|
0.9 |
| PP26 |
|
132.7 |
|
|
32.2 |
|
| PP27 |
|
|
139.8 |
|
|
1.0 |
| PP28 not tested |
|
166.4 |
|
|
|
|
| PP29 |
|
|
153.24 |
|
|
0.95 |
| CTR mean value of lot |
158.2 |
154.5 |
154.4 |
86.3 |
35.1 |
0.93 |
| CTR in % of original |
100% |
100% |
100% |
54.5% |
22.7% |
0.6% |
Figure 3 The change in current transfer ratio as
function of neutron irradiation. At a does rate of 7x1011
3 out of 8 optocoupler still worked. Tests at CERN show that
by increasing the gain of the circuit in which the optocouplers are
used it should be possible to use them up to about 3x1012 n/cm2.
4) Test of microcontroller AT90S1200.
Five AT90S1200 were programmed with a test pattern in 1024
bytes of flash and 64 bytes of EEPROM memories. They were subjected to
9x1012 All devices were still working without any
memory erased after the tests.
Last Updated on 16/11/98