In order to better understand possible anisotropies in the azimuthal distribution of SpaceCharge (see, for example, zerobias data from day 47 of 2004), I have examined the signed DCA (sDCA) aziumthal distributions from several productions. I have separated these distributions into a static component and a dynamic component by determining <sDCA> in each phi bin for each dataset examined, and then looking at the differences from this mean. The mean does not truly equal the static component, but it is very helpful to subtract this component in order to see the the time-evolving component as both components are of similar magnitudes.

In the plots below, the first row shows the <sDCA> value for each phi bin (the bins are aligned along TPC sectors going from 2 o'clock, 1 o'clock, 12 o'clock, .... , 3o'clock with increasing phi). In the subsequent rows, I plot sDCA-<sDCA> versus day (with each phi bin offset) to see what's happening on sub-day time scales, versus day in a colored 2D graph to see what's happening on larger time scales, and versus SpaceCharge to see what's happening versus luminosity.

Additional comments below the plots.

2004

2004 AuAu200	early RFF data	FF data	late RFF data
<sDCA>
sDCA - <sDCA> vs. day
sDCA - <sDCA> vs. day
sDCA - <sDCA> vs. SpaceCharge

The <sDCA> values appear to have fluctuation on the +/-200 micron scale in azimuth. The FF and late RFF data show a feature at phi~3 that is probably due to backgrounds from the collider entering the TPC and causing SpaceCharge distortions in only one region in phi. All of the fluctuations seem to subside to well below 100 microns at the lowest luminosities, implying that <sDCA> perhaps does represent well the static misalignments/distortions.

For the early RFF data, there are some unusual structures. The above SpaceCharge plot for this data was set so that the range of sDCA at higher luminosities could be viewed. Here is a plot of the same data with the range modified to see more clearly the low luminosity data, for which the fluctuations are again well below 100 microns.

2005

For the 2005 data, I wanted to compare the P06ic production (which includes SVT and SSD in tracking) with the P06ib production (TPC-only tracking). However, only a small number of tracks actually included SVT or SSD hits in the P06ic data sample.

2005 CuCu	P06ib 200GeV RFF data	P06ic 200GeV RFF data	P06ic 62GeV RFF data
<sDCA>
sDCA - <sDCA> vs. day
sDCA - <sDCA> vs. day
sDCA - <sDCA> vs. SpaceCharge

Here, we again see <sDCA> distortions on the order of +/-200 microns, which are there independently of the SVT and SSD usage. This time, the feature at phi~3 is much more prominent, subsiding as the days progressed. It should be considered that the dip in this particular distortion is still atop the ~400 micron peak in the <sDCA> distribution at the same phi, so it is not reversing, but just decreasing relative to the average. A compensating feature appears at phi~4.5, which should exist if the E-by-E SpaceCharge code is working properly since it tries to pull the mean of all sDCAs to zero. It is difficult to say exactly what this means in terms of how the backgrounds causing this look.

There appears to be an "event" of some sort for only the first few runs on day 40, as seen by the offset sDCA-<sDCA> plots.

The 62 GeV CuCu data appears to have smaller static and dynamic distortions.

Gene Van Buren