Tagging of charged particles in the CSI barrel

This document describes how to use the software available to tag the CSI blocks hit by charged particles. The information about the CSI detector can be found here and the information on how the tagging is performed is here.

Introduction.

The purpose of the CSI tagging code is to mark (tag) the CSI blocks that have been hit by charged particles and to calculate the "total CSI energy", the "untagged energy" and the "tagged energy".

The input to the tagging routines are the following groups:

• GROUP_CSI_HITS - the CSI blocks that have non-zero energy
• GROUP_GEO_VERTICES and GROUP_GEO_TRACKS- information about the charged particles detected in the event.

• GROUP_CSI_TAGS - contains the tagging information
• three numbers - total, tagged and untagged energies in the CSI.

Tagging routines

The tagging routines are prototyped in tagCsi.h

All the routines return a status code, 0 neams success, non-0 means error.

tagCsi_makeTags

will tag the array of csiHits and return a pointer to the malloced array of tags (csiTags). After use, csiTags should be free()ed.

tagCsi_doEvent

takes an event and generates the GROUP_CSI_TAGS.

tagCsi_countEnergy

takes an array of csiHits (pointer to GROUP_CSI_HITS), and array of csiTags (pointer to GROUP_CSI_TAGS) and computes the tagged and untagged CSI energy.

tagCsi_getEnergy

takes an event, generates the tags, computes and returns the tagged and untagged CSI energy, discards the tags (does not create GROUP_CSI_TAGS).

Examples

Generate the tags and compute tagged and untagged energy:

#include <tagCsi.h> ... itape_header_t *event; /* pointer to the event buffer */ int eventSize; /* size of the event buffer */ ... float etot,etagged,euntagged; ... tagCsi_doEvent(event,eventSize); /* produce the tags */ tagCsi_countEnergy(event, data_getGroup(GROUP_CSI_HITS), data_getGroup(GROUP_CSI_TAGS), 0, &etot,&etagged,&euntagged); ...

Just compute the tagged and untagged energy:

#include <tagCsi.h> ... itape_header_t *event; /* pointer to the event buffer */ ... float etot,etagged,euntagged; ... tagCsi_getEnergy(event, &etot,&etagged,&euntagged); ...