EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

Beam Threader

The threader simulates beam steering through a machine with field and alignment errors in situations where the beam does not circulate and the closed orbit cannot be measured.

If enabled, threading is executed whenever a trajectory or closed orbit search is carried out by the TWISS module.

The following MAD-X commands control the action of the threader :



option, threader ;
enables the threader

when set, the threader checks at all monitors the difference with respect to the stored orbit there (from keeporbit) if useorbit is present. The threader then provides kicks (if possible) to reduce the orbit difference below the maxima specified on the threader command. This procedure allows to thread with orbit bumps present



threader, vector = {xmax, ymax, att} ;
sets the parameters for the threader
xmax, ymax : orbit excursion (at a monitor) at which threader acts
att        : attenuation factor for the kicks applied by the threader
defaults   : {0.005, 0.005, 1.000}




Hans Grote, 31.10.2008