Performance of CIZ

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Table 1 gives you an overview of the developing hardware status of CIZ from 1995/96 to 1997/98 winter shutdown. A L4-histogram showing the CIZ hitmap for run 190020 is given in Figure 1.

History of hardware status from 1996 to 1997
Ring Number (0-14)	Dead since...	Run number
2	25.06.96	144360
5	06.07.96	147550
4	06.08.96	154165
0	11.09.96	158750
13	05.03.97	178322
valid until end of 97 run period

Table 1

Figure 1

In the winter shutdown 1997/98 the CIZ has been completely re-wired. During the entire 1998 datataking period all rings have been operated fully efficient using the nominal HV-settings.

On the 19th Febuary of 1999 ring 10 of CIZ had to be degraded due to a broken sense wire. The chamber could be operated with all other rings at their nominal HV-settings. For a stable running the trip limit on cathode number 10 had to be adjusted up to order(125muA). On August the 18th the current on cathode 10 increased drastically. The CIZ could be switched on only by degrading 5 rings (8 - 12). Ring 8 and 12 could be regained to full efficiency after optimizing the HV-settings. Two month later on October 23 ring 12 again had to be degraded. This status of 4 dead rings (9-12) persisted until the end of 2000 running period. The situation is summarized in Table 2 and a L4-histogram showing the CIZ hitmap for run 257633 is given in Figure 2.

History of hardware status from 1999 to 2000
Ring Number (0-14)	Dead since...	Run number
10	19.02.99	235158
8 - 12	18.08.99	250680
9 - 11	21.08.99	251301
9 - 12	23.10.99	257620
valid until end of 2000 run period

Table 2

Figure 2

The hardware status of CIZ is accounted for in the Monte Carlo simulation by the CYSW bank. In the given example ring 10 is degraded since the efficiency of the four wires of ring 10 has been set to zero. All other wires have an efficiency of 85%. The setting is effective from the run number (here 235158) which is specified by the expert. To write it into the data base use the command: ndbint '"cysw_version"'

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