Results of radiation test of UF-PNPI HV distribution board prototype, made in UC Davis on April 10-11 2003.

Test log:

Test #	Component/board area name	HV Channel/Master	Dose/fluence	Dose rate	Beam current	Observations
1	HV channel 1,2,3 and around	4 KV	<10 rad	0.2 r/s	10 pA	HV diode GP02-40 in channel 2 shorted dead very soon under high voltage (after just a few rads)
2	HV diode GP02-40 on a fixture	1 KV	10 rad	0.2 r/s	10 pA	OK
3	HV diode GP02-40 on a fixture	2 KV	10 rad	0.2 r/s	10 pA	OK
4	HV diode GP02-40 on a fixture	3 KV	10 rad	0.2 r/s	10 pA	OK
5	HV diode GP02-40 on a fixture	4 KV	10 rad	0.2 r/s	10 pA	Failed (short)
6	2 HV diodes GP02-40 in series on a fixture	4 KV	10 rad	0.2 r/s	10 pA	OK
7	2 HV diodes GP02-40 in series on a fixture	4 KV	100 rad	0.2 r/s	10 pA	OK
8	2 HV diodes GP02-40 in series on a fixture	4 KV	770 rad	0.2 r/s	10 pA	OK
9	2 HV diodes GP02-40 in series on a fixture	4 KV	400 rad	1.15 r/s	50 pA	OK
10	HV transistor BUH2M20 on a fixture	1 KV	2000 rad	1.15 r/s	50 pA	OK
At this point HV diodes in all channels were removed. Solution is to use two diodes in series (see test 23), but modifying prototype in UCD is problematic. All tests of the board from this point were done without diodes.
11	HV channel 1,2,3 and around	3.6 KV	10 rad	1.15 r/s	50 pA	OK
12	HV channel 1,2,3 and around	3.6 KV	100 rad	1.15 r/s	50 pA	Current measurement in ch 2 and 3 jumps 500 nA. Not related to radiation (calibration problems)
13	HV channel 1,2,3 and around	3.6 KV	1000 rad	1.15 r/s	50 pA	OK
14	DAC and ADC	3.6 KV	1000 rad	2.3 r/s	100 pA	OK
15	Bus drivers	3.6 KV	1000 rad	2.3 r/s	100 pA	OK
16	Test DAC + multiplexers	3.6 KV	1000 rad	2.3 r/s	100 pA	OK
17	HV channel 1,2,3 and around Very large dose test	3.5/3.8 KV	10^11 p/cm^2 ~13000rad	22 r/s	1 nA	Channel 2 stops regulating above about 3.2 KV, so the problem is certainly NOT HV transistor. To be investigated. Until 10^11 p/cm^2was working fine. Failure is most probably due to huge dose rate and ionization.
18	LV regulators LM2990T-5.0-ND and LM1086IT-5.0-ND on a fixture	In: +-7V Out: +-5V	10^11 p/cm^2 ~13000rad	22 r/s	1 nA	OK
19	DAC and ADC	3.6/3.8 KV	4000 rad	1.08 r/s	50 pA	OK
20	Bus drivers	3.6/3.8 KV	4000 rad	2.15 r/s	100 pA	OK
21	Test DAC + multiplexors	3.6/3.8 KV	4000 rad	2.15 r/s	100 pA	OK
22	HV channel 6,7,8 and around	3.6/3.8 KV	5000 rad	2.15 r/s	100 pA	OK
23	3 chains of 2 HV diodes on a fixture	4 KV	5000 rad	2.15 r/s	100 pA	OK

Conclusions:

1. HV diode GP02-40 does not work under 4KV in radiation Two diodes in series work fine. This solution will be used in the system.
2. 5 Krad dose was given to all vital parts of the distribution board (HV channels, DAC and ADC, bus drivers and control logic, Test DAC, analog multiplexers) according to T.Y. Ling’s testing plan
3. All tests were done with the board and components completely powered and parameters were monitored during and after the test.