X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=TOF%2FREADME;h=b8f4bf4c510c0835e14b411e1c8f7c9f18cf53e2;hb=891efa0008e3246e2f7ebc6a5bf8cebccffae8ef;hp=13714a129db2e05431f1f122bf8bf8256f250bac;hpb=2825e4fb345c46ac5aac1547c42c3a924c8d85cb;p=u%2Fmrichter%2FAliRoot.git diff --git a/TOF/README b/TOF/README index 13714a129db..b8f4bf4c510 100644 --- a/TOF/README +++ b/TOF/README @@ -1,11 +1,11 @@ - README file for ALICE Time Of Flight Detector Oflfine Code + README file for ALICE Time Of Flight Detector Offline Code ========================================================== Intorduction ------------ This is a short overview of the TOF code within the AliROOT framework. - +Some additional details have been introduced to Structure --------- @@ -163,6 +163,185 @@ Till today (February 6th 2008), it contains the following classes AliTOFQADataMakerRec: +TOF Calibration: +---------------- + +1. Online Calibration + +1.1. New Calibration Schema + +1.1.1. Configuration + +The online calibration which is performed by the TOF preprocessor is +configured according to a CDB object (stored in /TOF/Calib/Config), where +a flag for the computation of the delays is set according to the type +of data taking (cosmics ---> kFALSE / beam ---> kTRUE), and where the +starting validity of the calibration objects that will be written in the +OCDB is defined (see sec. 1.1.3.). The data are stored in the CDB object +as entries in a TMap, with IDs "ComputingDelays" and "StartingRun" +respectively. + +1.1.2. Objects + +- AliTOFChannelOnlineArray: array of floats containing the delay value + calculated for each TOF channel by the TOF preprocessor starting from + the DAQ DA for PHYSICS runs (see TOFda.cxx). Inheriting from TObject. + +- AliTOFChannelOnlineStatusArray: array of chars defining the status for each + TOF channel according to the processing of the data coming from PULSER and + NOISE runs (TOFpulserda.cxx, TOFnoiseda.cxx). The status is defined also + according to the FEE map written in the DCS FXS, where the status ON/OFF + of the channels is stored. The first (least significant) two bits refer to the + FEE status, the second two to the pulser data, and the third two to the noise + data, leaving the last two empy. The status is always (FEE/pulser/noise) + defined as: + 00 --> Unknown; + 01 --> Good; + 10 --> Bad. + Inheriting from TObject. + +1.1.3. OCDB + +- /TOF/Calib/ParOnlineDelay: directory where the AliTOFChannelOnlineArray + calibration objects are stored, with validity [0, 999999999], increasing the + sv number every time. After offline calibration takes place, in case a reset + is needed at run XYZ, the validity changes to [XYZ, 999999999], again + with increasing sv. + +- /TOF/Calib/Status: directory where the AliTOFChannelOnlineStatusArray + calibration objects are stored, with validity [current_run, 999999999]. In + case of a PHYSICS run, the update occurs only if the FEE map has changed. + In case of a PULSER/NOISE run, the update occurs once at the very end of the + processing, so to merge the information from the FEE status map and those + from the TOFpulserda/TOFnoiseda. + +1.1.4. Reference Data + +- /TOF/Calib/DAQData: directory to store the histograms at run level that + are produced by the TOFda. + +- /TOF/Calib/DCSData: directory to store the data that come out from the + processing of the TOF DCS DPs. + +- /TOF/Calib/PulserData: directory to store the histograms that are produced + by the TOFpulserda. + +- /TOF/Calib/NoiseData: directory to store the histograms that are produced + by the TOFnoiseda. + +- /TOF/Calib/FEEData: directory to store the histogram reproducing the FEE + status of the TOF channels. + +1.1.5. Usage in Reconstruction + +During reconstruction, both the AliTOFChannelOnlineArray and the +AliTOFChannelOnlineStatusArray corresponding to the current run have to be +loaded from OCDB in the AliTOFReconstructor class instance. From there, +they are passed to the AliTOFClusterFinder, where the status of the channel is +used in order to decide whether to use it or not, while the delay is used to +calibrate when the offline calibration information is not yet available. + +1.2. Old Calibration Schema + +1.2.1. Configuration + +No OCDB configuration entry is foreseen. + +1.2.2. Objects + +- AliTOFChannelOnline: object containing the value of the delay for a + certain TOF channel. Inheriting from TObject. An TObjArray of 157248 of such + objects is used to store the information coming from the TOF online + calibration. Inheriting from TObject. + +- AliTOFChannelOnlineStatus: object containing the status of a TOF channel + as determined during the reading of the FEE map/ during a pulser run/ + during a noise run. Three TObjArray objects of 157248 of such objects should + be present in the OCDB for each run: one related to the FEE status of the + channels, one related to pulser run results, and one related to noise + run results. The status is defined as: + 00 --> Unknown; + 01 --> Good; + 10 --> Bad. + Inheriting from TObject. + +1.2.3. OCDB + +- /TOF/Calib/ParOnline: directory where a TObjArray of 157248 AliTOFChannelOnline + calibration objects are stored, with validity [0, 999999999], increasing the + sv number every time. After offline calibration takes place, in case a reset + is needed at run XYZ, the validity changes to [XYZ, 999999999], again + with increasing sv. + +- /TOF/Calib/HW: directory where a TObjArray of 157248 AliTOFChannelOnlineStatus + calibration objects are stored, with validity [current_run, 999999999], as + obtained from reading the FEE map from the DCS FXS. The update occurs only if + the FEE map has changed. + +- /TOF/Calib/Pulser: directory where a TObjArray of 157248 AliTOFChannelOnlineStatus + calibration objects are stored, with validity [current_run, 999999999], as + obtained from a pulser run. + +- /TOF/Calib/Noise: directory where a TObjArray of 157248 AliTOFChannelOnlineStatus + calibration objects are stored, with validity [current_run, 999999999], as + obtained from a noise run. + +1.2.4. Reference Data + +- /TOF/Calib/DAQData: directory to store the histograms at run level that + are produced by the TOFda. + +- /TOF/Calib/DCSData: directory to store the data that come out from the + processing of the TOF DCS DPs. + +- /TOF/Calib/PulserData: directory to store the histograms that are produced + by the TOFpulserda. + +- /TOF/Calib/NoiseData: directory to store the histograms that are produced + by the TOFnoiseda. + +- /TOF/Calib/FEEData: directory to store the histogram reproducing the FEE + status of the TOF channels. + +1.2.5. Usage in Reconstruction + +During reconstruction, the TObjArray of AliTOFChannelOnline and the three +TObjArray objects of AliTOFChannelOnlineStatus coming from the FEE map, the +pulser run data, and the noise run data corresponding to the current run have to +be loaded from OCDB in the AliTOFReconstructor class instance. From there, +they are passed to the AliTOFClusterFinder, where the status of the channel is +used in order to decide whether to use it or not, while the delay is used to +calibrate when the offline calibration information is not yet available. + +2. TOF Offline Calibration + +2.1. Object + +- AliTOFChannelOffline: object containing the calibration parameters for + each TOF channel that should correct both for the delay introduced by the + electronics and the hardware, and for the time slewing effect. A TObjArray + of 157248 of such objects is stored in the CDB to perform refined calibration + during reconstruction. Inheriting from TObject. + +2.2. OCDB + +- /TOF/Calib/ParOffline: directory containing the CDB entry corresponding to the + offline calibration of the TOF as stored in a TObjArray object of 157248 + AliTOFChannelOffline objects with validity [0, 999999999], increasing the + sv number every time. In case a reset is needed at run XYZ, after collecting + the statistics necessary to the offline calibration (when the online + calibration object becomes valid again), the validity changes to + [XYZ, 999999999], again with increasing sv. + +2.3 Usage in Reconstruction + +The TObjArray of 157248 AliTOFChannelOffline objects is retrieved for the current +run in AliTOFReconstructor, and passed to AliTOFClusterFinder. As soon as enough +statistics is collected for every channel, since the validity +of the offline calibration object was set, for each channel with a valid +status, the calibration is performed using the calibration parameters present in +this TObjArray of AliTOFChannelOffline. + Authors: --------