26 Apr 2004
We shipped Fasti electronics to TNG, all travels went good, and in
the last two weeks, we tested it at the telescope with Nics. Starting with a very high RON (Read Out
Noise), we worked to reduce the noise till a (nearly) good
result.
We reached an acceptable noise level too late to let FASTI
installed for normal operation, so we plan a second expedition, in the near
future to finalize the installation.
We evaluated the RON (Read Out Noise) with the procedure described in
(Hunt,
94) and with a procedure suggested by Oliva (Priv.Comm.).
The results, to be taken only as an indication of astronomical performances,
should still be improved. All reads have been taken with a 400kHz read out.
To be comparable with Arcetri measures, we report only two
quadrants.
The global noise is around 4.2 counts (~33 electrons, integrations
up to 50s, data below),
while the Oliva evaluator gives 5.5 counts (45 electrons,
integrations of 2s). In analogous condition the present electronics
gives 4.5 counts (35 electrons, Oliva evaluator)
The equivalence between counts and electrons inside the detector has to be measured,
but preliminary estimates lead to 8 electrons/counts.
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