HRS Timing & Related Issues

Vincent SulkoskyMassachusetts Institute of Technology

SRC Collaboration MeetingFebruary 21st, 2010

Refresher on TriggersT1 (RHRS Main)T2 (RHRS Efficiency)T3 (LHRS Main)T4 (LHRS Efficiency)T5 (Coincidence RHRS&&LHRS)T6 (BB E-plane)T7 HANDT8 (1024 Hz clock)

HRS Trigger DefinitionsT1/T3: “AND of the OR’s”:

S1-or&&S2-or“AND” of left-right PMTs of S1“AND” of left-right PMTs of S2mTypically S2m right PMTs are delayed 20 ns wrt S2m left PMTs (self-timing)“S2-or” delayed wrt “S1-or”: 20-30 ns

T2/T4: (2 out-of 3 trigger) includes GC and exclusive to T1/T2

HRS retiming (strobe): “S1-or||S2-or”

HRS Trigger Diagram

Coincidence Trigger Diagram

HRS RetimingL1A directly from weldmentStrobe (≥ 60 ns after L1A)Overlap results in retimed L1AIf no overlap, circuit times out and

produces a delayed retimed L1A ~ 200 ns later to force gates and stops, i.e., this happens for T8 triggers.

HRS Timing IssuesR-HRS S2m was not setup for self-

timingSome PMTs show considerable after-

pulsingHRS scintillator class by default takes

the latest hit (right before the stop)See multiple peaks in both HRS

scintillators, though appears to be localized more to S2m

HRS Self-Timing (g2p)

L-HRS, Dec. 2011Black: Right; Red: Left

HRS ‘Not’ Self-Timing (g2p)

R-HRS, Dec. 2011Black: Right; Red: Left

After-pulsing LHRS S1L PMTs

After-pulsing LHRS S1R PMTs

RHRS S1L PMTs

RHRS S1R PMTs

L-HRS Trigger TDCs

R-HRS Trigger TDCs

LHRS S2m

LHRS S2m: Double Peaks

Clearly not a left-right PMT issue!

LHRS S2m: Double Peaks

LHRS S2m: 2-to-1 Peak

LHRS S2m: Self-timing(?)

Plan to Move ForwardDetailed timing diagrams from

Spring 2011Work with Igor and Tai while both are

hereat JLabGoals: understand the data and

develop an algorithm to determine the correct tof