Changing Detector Size and Position

In principle some changes can be made by changing the GEDP and GEDS banks but there are severe restrictions on this because, for reasons on efficiency, some of the contents of these banks is ``hardwired'' into the code that uses them. Execution time control is limited to the following:-

• Enabling/Disabling Parts of the detector. See section 12.2.4.

• Switching elements into simple approximation mode (perhaps several levels of approximation).

• Defining exact measurements and position of the elements. The symbolic commands $translate_geom and $rotate_geom can help here. Take care when moving a calibration source to move all the elements; there is no system to apply a translation or rotation to a group of related regions. See for example calibration_8li_generic.cmd.

You cannot in general:-

1. Change region priorities.

2. Change the lists of owned, internal and external regions.

3. Add or remove primitives or change their type, operation or surface information.

The only exception is the inner calibration source which is generic, see section 12.3.2