A FIRST LEVEL TRIGGER APPROACH FOR THE CBM EXPERIMENT

ISBN: 9783954250080 Géneros: PD Sinópsis: In view of the very heavy CBM experiment constraints on the first level trigger no conventional trigger is obviously applicable Hence a fast trigger algorithm with the goal of realization in reconfigurable hardware had to be developed to fulfil all requirements of the experiment In this connection the general Hough transform which is already utilized in several other experiments is used as a basis This approach constitutes further a global method for tracking which transforms all particle interaction points with the detector stations by means of a defined formula into a parameter space corresponding to the momentum of the particle tracks This formula is of course developed especially for the given environment of CBM and defines thus the core of the applied three dimensional Hough transform As the main focus of attention is furthermore on the realization of the needed data throughput the necessary complex formula calculations give reason to outsource predefined formula results in lookup tables This circumstance offers then collaterally the possibility to utilize any other sufficiently precise method like RungeKutta of fourth order for example to compute these lookup tables because this computation can be evidently done offline without any effect on the Hough transforms processing speed For algorithm simulation purposes the CBMROOT framework provides the module ‚htrack which is written in the programming language C This module includes many analyses for the determination of algorithm parameters which can be even executed automatically to some extent In addition to this there are of course also analyses for the measurement of the algorithms quality as well as for the individual rating of each partial step of the algorithm Consequently the milestone of a customizable level one tracking algorithm which can be used without any specific knowledge is now obtained Besides this the investigated concepts are explicit