SEM - HOW TO		M. Zeier July 23, 2001
	============

This file:
~cdaq/gen/Documents/tbpm_guide.txt

Modes
=====

EVENT mode: The beam position is determined for each event and
the output voltages are acquired in an ADC. To determine the beam
profile/position the run needs to be analyzed.

STATIC mode: The following average values of the beam are
determined: x centroid, y centroid, x diameter and y diameter
These values are updated after each helicity period. The values get stored in
scalers via V to f converters. The information is also available
on the TBPM-SMU Remote Display to the left of the Online Replay
Terminal. The display gets updated only every few seconds.

The standard mode during production will be STATIC mode. EVENT mode will only
be used to calibrate the raster currents vs beam position.

Operation
=========

The SEM electronics is  down in the hall can be turned on remotely in the
electronics room. There are two cards in the bottom NIM bin of
rack CH03B19. It is important to turn on the SMU unit first,
otherwise the NIM bin will trip. The SMU card has a switch to
chose between EVENT mode and STATIC mode.
The EVENT electronics needs to be on for either operation while
the STATIC electronics can be off for EVENT mode.

In case of weird behaviour stop the run and power-cycle both electronics. 

Documentation
=============

More detailed information can be found in the black binder
(TBPM/SEM User's manual) to the upper left of the Online Replay
terminal, above the TBPM-SMU Remote Display unit.

Even more detailed information can be found in the two grey
binders (Design Documentation) on the wooden book shelf.

Experts
=======

Marko Zeier