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The table lists the constants changes that have been implemented. There are two sets of constants: Front-end(online) and Back-end(offline). Front-end means that the constants are applied online so that the raw data (.xtc files) already has them applied. Linearity refers to the electronics linearity constants. Back-end refers to the offline constants that are applied in OPR (IR-2 conditions database). Backend constants can applied retro-actively. Eg. On September 10th we installed back-end constants that are applicable to any data taken after 14th May. However any data processed before 10 September will not have these constants applied.

CONSTANTS CHANGES
Date Installed Run Validity Front-end change Front-end change details Back-end change Back-end change details
Apr 28 99 2031-2350 Yes Best guess gains, digicut 5 MeV Yes All set to 1.0
May 14 99 2351-7339 Yes MIP/QC gains No No
June 10 99 2351 onwards No No Yes Mip/QC correction applied for all runs from 2351
Aug 12 99 7340-8354 Yes New linearity, Digicut 2.5 MeV,new gains from bhabha's or MIP/QC where no bhabha Yes All Set to 1.0
Aug 24 99 8405-9080 Yes New linearity No No
Sep 7 99 9081-9726 Yes New linearity No No
Sep 10 99 2351 onwards No No Yes Source constants: Valid for all previous front-end constants from 14th May (run 2031) onwards. Data processed before 10 September has back-end constants as above. Data processed afterwards has valid source constants for all dates.
Oct 19 9839-9905 Yes New Linearity, New gains from source constants Yes Incorrectly set 9839-9905
Oct 22 9906 onwards No No Yes All set 1.0 start validity date 00:00:00 Oct 21 99

Colin Jessop
Last modified: Mon Oct 20 16:00:00 PDT 1999