Detector simulation is accomplished by passing the four-vectors of all the particles produced by the Monte Carlo generator into a computer simulation of the OPAL detector.
This is done by the GOPAL [90] Monte Carlo program. This is based on the CERN GEANT [91] simulation package. The event generator produces four-vector files for the particles. These are passed to GOPAL which simulates the detector response, all the default constants for each of the OPAL subdetectors are also passed into GOPAL. The output of GOPAL is a copy of the constants used and the simulated ``raw data.'' These can then be passed into the ROPE program in the same way as the ``real data'' from the OPAL detector. DSTs can be produced and analysed in the same way for the Monte Carlo as is done for the data.
A schematic for this process is shown in figure 5.6.
