Results from UC Davis 63 MeV proton beam irradiation test.
March and April 2000 test
Conditions.
The measurements were taken at UC Davis by M. Tripathi (mani@physics.ucdavis.edu) and
B. Holbrook (bholbrook@ucdavis.edu) at the following conditions:
- A 63.3 MeV proton beam at an incident beam angle of 5 degrees with respect to the normal to the board.
- Six anode front end 16 ch boards with CMP16E chips on them were tested, boards 21, 23 and 26 in March,
boards 16, 19, 20 - in April.
- The following current and voltages were measured:
* I (amps) - total current;
* Vd (volts) - discriminator voltage;
* Va (volts) - amplifier voltage;
* Vc (volts) - power regulator voltage.
Data and specific operating conditions, results (boards 21, 23 and 26).
Board # 26
- received 3 successive exposures for a total of
13 krad
:
- 1 krad at beam current of 200 pA for approx. 4 minutes;
- 3 krad at beam current of 200 pA for approx. 11 minutes;
- 9 krad at beam current of 1 nA for approx. 7 minutes.
For the presentation the data were normalized to their initial values at beginning of the first exposure.
See results for the board # 26 vs (
time
) and (
dose
). The vertical discontinuities in the graphs are due to the DAQ bin resolution.
Board # 23
- received 2 successive exposures for a total of
30 krad
:
- 15 krad at beam current of 2 nA for approx. 5 minutes;
- 15 krad at beam current of 2 nA for approx. 5 minutes.
See results for the board # 23 vs (
time
) and (
dose
, up to first 15 krad).
Board # 21
- received 2 successive exposures for a total of
60 krad
:
- 30 krad at beam current of 4 nA for approx. 5 minutes;
- 30 krad at beam current of 4 nA for approx. 5 minutes.
See results for the board # 21 vs (
time
) and (
dose
, up to first 30 krad).
Data and specific operating conditions, results (boards 16, 19 and 20).
The figures below plot the current and voltages vs time and dose in logarithmic and linear scale.
The data were taken with a sample rate of 60 1/sec. The each 15-th point was plotted.
Board # 16
- received one exposure of
300 krad
at beam current of 20 nA for approx. 11 minutes;
Board # 19
- received one exposure of
600 krad
at beam current of 40 nA for approx. 11 minutes;
Board # 20
- received one exposure of
180 krad
at beam current of 40 nA for approx. 200 sec.
Comments.
- No latch-ups or spikes were seen in 3 boards (21,23 and 26) after a total exposure of about 100 krad.
- The amplifier and power regulator voltages do not recover immediately after irradiation.
- The current draw starts to increase at the dose of about 5 krad for the board # 26
and at the dose of about 1 krad for the boards ## 23,21. Note that the dose rates were
about of 0.25 krad/min and 3-6 krad/min for the boards #26 and ##21,23 correspondingly.
- At large doses (boards ## 16, 19 and 20) no latch-up was seen as well. However, at about
230 and 200 krad the current started dropping in boards 16 and 19 respectively. This could be
an indication of the fact that the chip had indeed died after this dose. Note that the dose rate for chip #19
was twice as much as for chip #16.
Discussion.
(N.Bondar, T.Ferguson, T.Y.Ling, N.Terentyev, M.Tripathi)
- For reminding - the neutron fluence and total ionizing dose (TID) corresponding to
10 year LHC operation at full luminosity (10 years =5*10**7 s at luminosity L = 10**34)
are 6.2*10**11 n/cm**2 and 1.78 krad in ME1/1 (for En > 100 keV). This is an extreme case.
For all other chambers the levels of radiation are less by at least an order of magnitude (see
a test plan
).
For comparison the total ionizing dose resulting from the 60 MeV protons is 14 krad for the
fluence of 10**11 p/cm**2. Irradiating with protons of energy in the 60 MeV to 200 MeV range
is considered as a practical and effective method for testing the electronics for total dose effect
(see details in the
test plan
and references therein).
- the total current of the anode front end card # 26 begins to increase after total dose of 4 - 5 krad
which is 2.5 times higher than the maximum neutron TID in ME1/1. It looks like the observed effect
depends from the rate the dose was delivered with. For two other boards (21,23) the current is
raising after TID of 1 krad (!), but for them the dose rate was 3-6 krad/min while for the board # 26
the rate was about 0.25 krad/min. The expected LHC neutron dose rate at ME1/1 is 5 orders of
magnitude lower. We should take the rate effect into account planning next set of the measurements
at starting dose rate, say, of 0.05-0.1 krad/min.
- In this run only static parameters have been tested and monitored. The basic specifications parameters,
such as threshold, noise and slewing time can be more sensitive to the TID. The complete set of measurements
including all parameters above as function of radiation level is planned for the new chips at UC Davis
in May-June. The goal (see T.Y.Ling's
talk
at FNAL and Florida) is to test everything to 3 times the ME1/1 dose
including also such effects as Displacement, SEU and SEL at the fluence equivalent to the neutron fluence
of 2x10**12 n/cm**2 and TID effect at 5 krad.
Back to radiation test page
Last modified: Wed Aug 09 11:20:00 CST 2000
teren@fnal.gov
Conditions.
Data and specific operating conditions,
results (boards 21, 23 and 26).
Data and specific operating conditions,
results (boards 16, 19 and 20).
Comments.
Discussion.