Event Codes for the Cu beam

Main event codes for HXR/SXR running (with permission from Carolina Bianchini Mattison):

Detailed picture of event codes and modifier bits

Relative timing of the event codes

LCLS timing operates at 360 Hz; each 360 Hz interval is called a "time slot".  The time slots iterate from 1 to 6 and then cycle back to 1 again.  So, time slot 1 (or any particular time slot) occurs every 6 360Hz intervals or 60 Hz.  In addition to that, a set of markers are generated to distinguish the consecutive sets of time slots.  A 60 Hz marker is attached to every set of 6 time slots; a 30 Hz marker is attached to every other set of 6 time slots; a 10 Hz marker is attached to every 6th set of time slots, and so on down to 0.5 Hz.  Thus, the sequence of time slots and markers looks like

I hope you get the idea...

A set of event codes maps to the occurrence of these time slots in the following manner.

There are also event codes 10, 20, 30, 40, 50, 60.  These are generated such that 10 = 11+41, 20=21+51, 30=31+61, 40=11+41, 50=21+51, 60=31+61; i.e. they are all 120 Hz and occur for two different timeslots each.

Shared Beam Timing

When the copper LINAC is setup to deliver beam to both soft and hard x-ray lines it does so by preferentially sending hard x-ray beam on time slot 4 and soft x-ray beam on time slot 1.  LCLS only uses time slots 1 and 4 to deliver beam.  To get more than 60 Hz beam to either line requires the other time slot (1 or 4) to be used.  So, the shared delivery modes should look like so

and so on.  I hope you get the idea.  The general rule is that the lower rate beam line will always be delivered on its time slot (1=SXR, 4=HXR) and its beam rate marker (0.5 .. 60Hz), and the other beam line will consume the remainder of the time slots 1 and 4.

Special Event codes