Commissioning and running of sPHENIX

[Stefan Bathe <stefan.bathe AT baruch.cuny.edu>]

RHIC

- one long store overnight

- today’s plan

  - rebucketing (RF work)

  - likely to finish early evening

  - beam will be unstable, so of no use for us

- Angelika might need access for collimators

  - if so it will be a 5-60 min access

  - we might go to controlled access for that if need be

- still need to get crossing angle for STAR

- also outstanding:  stochastic cooling

  - that’s for next week

- plan:  bring up a couple stores overnight with 56 bunches for STAR

  - we will take advantage of that for MBD timing and data taking again tonight

STAR

- night went well

- not quite ready for physics yet

- rebucketing will help

- observed collision z vertex offset away from sPHENIX by 1-2 ns

sPHENIX

- had a productive night

- one long store from 0:35 - ~ 8:00am

- initial ZDC scaler coincidence rate 3 kHz, minutes later up at 8 kHz, then slowly decaying throughout the store 

- provided MBD-based Ll1 trigger to GTM in global mode, triggering read-out of MBD and GL1

- timed in MBD on scope

- took data with MBD and GL1, dozens of runs, MBD timing and HV scans

- wide timing (vertex) distribution (no surprise:  beams not re-bucketed)

- offset by ~ 10 ns towards North (inconsistent with STAR observation, RHIC cannot tell us z offset)

- charge distributions in South look good, but not in North

- we may just have been triggering on junk

- will know much more when we repeat this exercise tonight with re-bucketed beam

Here’s a link to the slides Mickey made after staying up all night analyzing MBD data:

sdcc.bnl.gov

- 

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Stefan Bathe

Professor of Physics
Baruch College, CUNY
and RIKEN Visiting Scientist

Baruch:                                     BNL:
17 Lexington Ave                      Bldg. 510
office 940                                  office 2-229
phone 646-660-6272                phone 631-344-8490
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