The nominal luminosity of LHC, 10**34 cm**-2*sec**-1, combined together
with the 7 TeV beam energy will create a very hostile radiation environment
in the detector experimental hall. The radiation tolerance and
reliability of electronics are important issues for the CMS electronics
(see
Ref.1 and
tutorials tut1-3 in Ref.2)
including the endcap muon CSC front-end electronics.
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 parameters of the EMU CSC anode front end boards vs TID have been
measured in the 63 MeV proton
beam at the UC Davis. A few unpowered boards also were irradiated by
the neutrons in the reactor at OSU.
The goal (see T.Y.Ling's
talk at FNAL and Florida)
was to test everything to 3 times the ME1/1 dose including
also such effects as Displacement, SEU (Single Event Upset) and
SEL (Single Event Latch-up) at the fluence
equivalent to the neutron fluence of 2x10**12 n/cm**2 and TID effect at
5 krad. Though we only have to look
for changes in the gain, noise, threshold and timing up to 5 krad we also
looked for latch-up at high doses (60-70 krad).
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Introduction.