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SLAC Aerial View. SLAC ESD looking anew at timing. The short-term (3 year) LCLS needs A long-term revamping of Klystron control A new look at the prototype NLC ideas Provide input to this meeting
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SLAC ESD looking anew at timing • The short-term (3 year) LCLS needs • A long-term revamping of Klystron control • A new look at the prototype NLC ideas • Provide input to this meeting • How do we join SLC timing to EPICS timing to run the LCLS injector and Argonne-supplied Undulator?
SLAC Timing System Specifications • Blue Book: • (~1968) • Resolution: 50 nSec • - Jitter: 15 nSec • - Main Trigger Line • Waveform: • + / - 400 Volts PEP – II: (~1998) - Resolution: 2.1 nSec - Jitter: 20 pSec - NIM Level Waveform: 0 to –0.7 V into 50 Ohms
Waveforms: 119 MHz and NIM Pulse FIDO Output PDU Output
PDU – SLC Style Sixteen channels per PDU; One channel shown
PDU, Backplane, and STB Counters Drivers
Kickers Single Beam Dumper Logic Beam Position Monitors PAU – pulsed analog read or write Toroid Charge Monitors Trigger Gate and Synchronizer Klystron Controls Gated ADC readout Some Triggered Devices
Software aspects • PDU is loaded with tables of delays (TMAT) • These tables are indexed by beam code • Beam code information is sent separately at 360 Hz (PNET) • This information was once 16 bits, now is 128 bits, plan is for at least 1024 bits. • 16 STB outputs are delayed as a function of beam code
Software aspects - 2 • PNET broadcast includes base beam code (#<32), high-order bits of pulse ID, modes, and beam code information as a function of mode. • Code can intervene to create more complex scenarios (beam code #>31) • PNET includes information for current pulse, next, and/or next+1 • Since 128 bits is not nearly enough, much information is a function of modes (near front of buffer) • This complexity is referred to as Regional Beam Codes
What is included in timing? • Stable phase reference • Per-pulse digital information • Preset timed data acquisition • Preprogramming of complex scenarios • Collecting beam-based acquisitions SLAC speak = BPM Buffered Acquisition • Data do not pass through any database • Correlation done on host machine using Pulse ID • Can all this be digital at 1GHz (or faster)?