Sphenix-tpc-l mailing list

[Takao Sakaguchi <takao AT bnl.gov>]

Dear All,

 Here are the minutes from the sPHENIX TPC meeting

today.

Takao
-------------------

------------------

Update on space charge simulation by Carlos
------------------

- There are couple of slides that were already shown in the
tracking meeting a few weeks ago.

- The idea is to see the position offset due to the distortion
of the electric field due to the ions left in the field cage.

- The delta-r of thee code that Carlos wrote produces the

similar trend as the one shown in ALICE TDR, but some

difference in the R-dependence is seen. Still under the

investigation. (50KHz operation)

- Question by TS is how stable this delta-r is when the

rate fluctuates from, say, 30 to 60 KHz. This is not studied

yet (Carlos's answer)

- sPHENIX has ~ 10 times smaller distortion.

- From slide 12, Carlos tried to see the number of ions

left in the field cage under the 50 KHz operation. FYI,

sPHENIX is operated at 15+ KHz, using PYTHIA 8.

(p+p case. later, Carlos will run HIJING. TS suggested

to run 10 PYTHIA events and pack into one event,

if it is easier).

- The number of ions left in the cage is increasing as the

number of events accumulated. TS is interested in seeing

the point that the number saturates.

- The number of ions should be converted to the ICD in order

to compare with ALICE TDR number.

---------------

Some discussion about simulation with Carlos
---------------

- Tomorrow (Tuesday), Carlos and Alan will sit down and talk

about how to advance the current TPC simulation, including

the field distortion study that Carlos did.

- Carlos agreed to report the outcome from the discussion to
the sphenix-tpc-l list.

- Yorito, after the meeting, mentioned that the IBF parameter

may affect to the result of the current study. It would be nice to

see the result with some change in the IBF parameter.

---------------

Electronics update report by TS.
---------------

- We are inclined to follow the the STAR iTPC electronics option.

- TS will keep in touch with iTPC group, and try to get preliminary

electronics for our TPC development.

Next meeting in two weeks, which is May 16.

Takao

--

Takao Sakaguchi
Brookhaven National Laboratory
Physics Department, Bldg. 510C
takao AT bnl.gov
Office: 1-631-344-3345