The calorimeter reconstruction code in ARTE-01-09

Changes since the previous versions


Data table changes

Here there is the list of tables which have been changed since ARTE-01-08 and which are relevant for the calorimeter digitization/reconstruction/analysis.

HITC table

  • GCAL: the field GCAL which was used to store the coded address of the hit cell has been removed.
  • GCCE: the field GCCE is now used to identify the hit cell. GCCE points to an entry of the GCCE cell description table. It points also to the ECHF and ECHS tables which are all parallel to the GCCE one. The GCCE entry superseeds complitely the old GCAL one. If the old value is needed, it can be found in the CEID field of the GCCE entry pointed.
  • ADC: The ADC value read by the read-out or simulated by the digitization modules minus pedestal.
  • ECBO table

  • LINK: added field.
  • ECHC table

    This table has been deleted. It was used for the channel calibration. Now the calibration data have been split into the ECHS and ECHF tables.

    ECHS table

    Slow update rate channel calibration table.

    ECHF table

    Fast update rate channel calibration table.


    Code modifications

    Many code modifications have been made in the digi and care modules, mostly for making possible to have a calorimeter reconstruction outside ARTE and to deal with the new ECAL calibration tables. More important than the routines which have been modified are the functionalities modifications listed below.


    Functionality modifications

    1. Initialization: The calorimeter reconstruction initialization is needed if you use HITC data. Starting from this version, if calorimeter digitization is required (which means that the routine dgcal is called), the care inizialization is triggered, if not already done. This is needed in order to set up appropriately some geometry tables (GCCE, GCGD, GNEI, GCAX) and the ECAL calibration tables (ECBO, ECHS, ECHF). A new geometry file is read in order to find out which ECAL boards and which ECAL channels are actually used. The default file is in $HB/$HBVERS/geo/ECAL/ecalboard.dat
    2. Digitization: during the digitization, only connected channels (which means channels connected to some board) are actually digitized. With digi level 0(default), the ADC field of the HITC bank is not filled. With level 1, it is filled with the (simulated) ADC count value (with pedestal).
    3. CARE first step: During this step the HITC bank gets the following changes. With dglev 1 the pedestal is subracted to the ADC field. With digitization level 2, the R field is filled with the expected error (in GeV) to the energy measured (Q field). At the end of the clusterization step, the RCCL bank is filled. The TX, TY fields of the RCCL bank are filled with the expected slope of a strait line track coming from the origin (0,0,0) and pointing to the position of the cluster (X,Y,Z). The (RCCL) CVE covariance matrix is filled with the expected values assuming that the cluster has been generated by an electromagnetic signal (gamma or electron). With dglev 0 or 1 the non-zero values are those relative to (X, Y); with dglev 2 the CVE is not zero for values (X, Y, E). All values are measured at the calorimeter position and can be different from the vertex one (due to bremsstrahlung, ionization losses, pair creation, magnet bending, secondary vertex origin .... and so on). The (RCCL) VCOG contains the covariance matrix of the spread of the (x,y) center position of the cells forming the cluster. As for the previous care versions, the links from the RCCL bank to others are not set during the first step.
    4. CARE second step: Taking advantage of external track data the calorimeter code does a second cluster finding and classify the clusters in charged and neutral ones. Links from the RCCL bank to the MTRA, HITC, RSEG are established. In the old version, the link between RCCL and MTRA was filled only once for cluster and it referred to the most important MC particle that gave origin to the cluster. In this version, for each cluster there is more than one relation per cluster: the linked tracks are globally responsible for at least 80% of the energy measured in the cluster and are stored sorted by the energy deposit. As before, the first linked track gave the most important contribution to the cluster.


    Known bugs in ARTE-01-09-r1


    References

    1. Progress report on the ECAL reconstruction software (PS-file), Hera-B Note 97-135 [Mauro Villa]



    9-Nov-98 Mauro Villa