The STAR experiment

Steve's caiibrations page contains most of the details:

http://www.star.bnl.gov/protected/spin/trent/calibration/calibration.html

I decided not to correct for SpaceCharge and GridLeak in the 62GeV p+p dataset from 2006. This decision was based on the following points. Note that the plots are from some of the early production of P06ie (the conclusions were made from a smaller pre-production sample, but I could make the plots with better statistics from the production).

Signed DCA

Signed DCA profile versus BBC sum (east+west), where the red markers are from using east-TPC-only tracks, blue is west-TPC-only, and black is all tracks combined:

Some observations:

• The lowest luminosity bin does not fit the pattern of the higher luminosity data (it seems to have only small distortions, which is what we would like to see!).
• For the rest, there appears to be some luminosity dependence, and it goes it the correct direction for this field (negative slope for positive field).
• The east and west TPC are offset from each other. My first guess on this was that the You do not have access to view this node wasn't doing it's job so well on the east, and this was causing a shifted sDCA. But other east-west differences show up (see the next section) which hint that the shorted ring may not be the problem.
• The overall effects are small, with sDCA values generally of a few hundred microns. A plot of the track-by-track sDCA can be found here, and I estimate that overall the sDCA is offset from zero by about 300-400 microns, with an RMS of about 500 microns (due to the luminosity range).

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Residuals

Global track residuals at low (left, BBC sum < 1e5) and high (right, BBC sum > 1.5e5) luminosities versus Z and padrow:

Key points:

• These distortions are quite small, producing residuals in the range of 100-200 microns.
• There is a notable east-west difference, and the distortions appear to be almost non-existent in the west. Some east-west differences have been observed in the past, but were atop a much larger distortion, and were considered not worth worrying about.
• Almost no z-dependence is at odds with our correction model.
• The high luminosity data appears less distorted than the low luminosity (which agrees with the sDCA plots above). Could it really be that what I am labeling as low luminosity (low BBC sum rate) is actually more distorted? Perhaps some backgrounds existed during the periods of low luminosity data, which went away during the periods of higher luminosity (which tended to be earlier during the 62 GeV running).

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Summary

First, it is worthwhile to note that our ionization distortion correction machinery is not set up for east/west differences. Using a sagitta error of 400+/-500 microns, here is the estimated error in transverse momentum reconstruction of primary tracks, in delta Pt / Pt^2 (fractional momentum error per GeV/c of momentum):

We can see that we expect something like an error pf 0.33% per GeV/c of Pt. This corresponds to an average error of 3 MeV/c on a Pt = 1 GeV/c track, and about 85 MeV/c on a 5 GeV/c track (with fluctuations of about +/-100 MeV/c from the mean). There are less than 20 million events with TPC information in this pp62 dataset (mostly the "mb" trigger). This will statistically limit any analyis from high-pt studies, precluding the need to have the data calibrated to higher precision than already exists in this uncorrected data.

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Gene Van Buren

I've updated my codes to do a more systematic investigation of the stability of the gains.  Instead of trying to get sufficient tower-by-tower statistics for different time periods, I'm looking at MIP peaks for single runs integrated over all towers.  Here's the plot:

Simulation of HBT effect from the daughter lambdas of sigma's or xi's, as shown in the graphs.

The charge to the Review Committee for evaluation of the HFT proposal is archived here. The online document can be found under http://hepwww.physics.yale.edu/star/upgrades/Draft-Charge.pdf

The TUP Review is scheduled for Dec. 7th, 2006, and will consist of material from the HFT, IST and HPD groups. The draft charge for the review will be similar to the HFT review charge, archived here: Tracking Review Committee Charge.

StarVMC/StarVMCApplication:

• StMCHitDescriptor
• StarMCHits
• Step
• StarMCSimplePrimaryGenerator

 

Example of setting the input file: StBFChain::ProcessLine ((StVMCMaker *) 0xaeab6f0)->SetInputFile("/star/simu/simu/gstardata/evgenRoot/evgen.3.root");

The high voltage control program has two configuration files that need to be created prior to the utilization of the program. Those files are:

1. default.ini

   This is the basic configuration file. In this file there is information about the high voltage database file, which box and CW-Base need to be turned on, serial line settings and other configuration stuff. This file do not need to be edited by hand. There is a special window in the high voltage program that can be used to modify this file.

 

There are a few commands for expert operation. They are:

1. Led Ampl. entry box

   This Configures the LED pulser amplitude. Enter the value and press [Set] to set it for all the tower crates

Steve Trentalange (on site all run) e-mail: trent@physics.ucla.edu
Phone: x1038 (BNL) or (323) 610-4724 (cell)

Oleg Tsai (on site all run) e-mail: tsai@physics.ucla.edu

SMD High Voltage Operation Manual

Version 1.00
11/12/03, O.D.Tsai

Overview

Overview

This program is designed to control the high voltage of  towers PMT's (Photo Multiplier Tubes). Each tube has an independent high voltage settings. Each PMT is connect to a CW-Base that controls the high voltage for the base. The CW-Base connects to a personal computer running Windows through a RS-485 serial line. The personal computer runs a LabView program that communicates to all CW-Bases in the system to set and monitor the high voltage on each PMT. 

Hello,
At todays meeting I'd like to present my my results on lambda correlations
http://www.star.bnl.gov/protected/hbt/radman/ffrff.htm

If it is not a problem I'd like to start no sooner than at