100 likes | 200 Views
Front-end quality database. G. Auriemma. Summary. Database of Eletis test results is available at the web page: http://auriemma.web.cern.ch/auriemma/TestBench/PZtestbench_1.htm Updated until 21/10/2006 (3968 cards) In the last version card quality indicators have been added (for each channel)
E N D
Front-end qualitydatabase G. Auriemma
Summary • Database of Eletis test results is available at the web page:http://auriemma.web.cern.ch/auriemma/TestBench/PZtestbench_1.htm • Updated until 21/10/2006 (3968 cards) • In the last version card quality indicators have been added (for each channel) • A summary database with a compact quality indicator for each card is also available G. Auriemma
Front panel of test bench at the end of the test run Cards in database A card which not passed the test with green light is not in the database This card must be rejected by Eletis (however its code is saved in a file) G. Auriemma
m s How we take the measures • Pulse 25000 times for each level S-curve • pre-calculate mean and r.m.s and… ENC • fit the gaussian … • A flag is set if the fit fails G-curve G. Auriemma
Chi-square as a measure of noisyness sfit Distribution of ENC on all positive cards @ Cdet= 33, 52, 100 @150 pF G. Auriemma
Comparison Chi square distribution with 4 dof Expected value=4 R.M.S=2.82 G. Auriemma
Correlation of Chi-square with the noise rate From bias scan Predicted Rate (3fC) (Hz) G. Auriemma
A compact card quality indicator • A very simple quality indicator has been proposed by Pierluigi: • 1 for a failed fit flag • 2 for a chi-square>20 • The sum over the channels of the card of this values is the compact card indicator • The summary database is a list of records of the type: • 4UE20900101381 ---------------- 0.0 (channels OK) • 4UE20900100949 --X------------- 2.0 (3° ch. noisy) • 4UE20900100762 ---------------- 0.0 (channels OK) • 4UE20900101860 --X------?---X-- 5.0 (fit failed on 10° ch.) • 4UE20900101284 ---------------- 0.0 • 4UE20900100013 ---X--------X--- 4.0 G. Auriemma
Selection produced by the indicator G. Auriemma
Conclusions • Some preliminary comparison with cards discarded in Frascati indicates that there is a strong correlation between the proposed indicator and problems with the card. • However some of the discarded cards showed no problems in the test at Eletis, and gave ENC’s well inside the averages. • All the cards that have been found to have dead channels where OK at the time of the Eletis test (post burn-in). G. Auriemma