Hit Density Rates for MVD

Wieman 5/08/04
revised 5/13/04
revised 5/15/04
revised 5/24/04
revised 9/8/04
corrected central single event 6/17/05
L=10^27 results 7/21/05

This version is for getting the average dose.

Don't use for peak

To estimate the number of pileup tracks

Note: dN/dz is written
as dNdz this is true for all derivatives in this analysis.

This simplifies to: (see space charge analysis code)

pseudo rapidity particle density for central

Measured min bias cross section at RHIC, F. Retiere

First history:

Minbias event rate, ZDC count rate

9.1 kHz at the start of a good run, see Run Log entry for run 5081011
03:21 21-March-2004, this must be at the time that the run has been started. This run peaks at 12 kHz according to the RICH scalers. There is another run that peaks higher at 15 kHz (phone call to Marco Van Leeuwen who checked RICH scalers. We will use 10 kHz as the nominal maximum rate because there will always be a start up delay.

Min bias cross section for ZDC coinc. (Jamie Dunlop)

The canonical design luminosity is 2X10²⁶/cm²/sec for Au+Au, so this is 5 times design.

selected luminosity for this analysis

Current Luminosity projections for late 2008 from

http://www.rhichome.bnl.gov/RHIC/Runs/RhicProjections.pdf

Does the integral look right? We expect 2 for the integral over ~-1<h<1

Find z at h = 1

guess value

found value

OK checks out

Convolute the dh/dz distribution over the diamond

convolution function

OK looks all right

central

min bias

One event hit density for silicon with central event at the center

Hit density for a central event on the outer surface of the MVD

Hit density for a central event on the inner surface of the MVD

Hit density rate for Au Au interactions at the maximum luminosity at a given radius, convoluted over the diamond.

(see cross check of this function at bottom of page)

Hit density rate on the outer MVD outer barrel

Hit density rate on the inner MVD outer barrel

Hit density with 4 ms frame read time MVD outer barrel

Hit density with 4 ms frame read time, MVD inner barrel

Probability of a cell of area DA having signal from more than one hit

Assume that 9 pixels get a signal from each hit

Pixel area

Pixel pileup probability for central collision

MVD outer barrel

MVD inner barrel

Pixel pileup probability for 4 ms integration, L = 10^27 Hz/cm^2

MVD outer barrel

MVD inner barrel

Probability for incorrectly associating a background hit with the track

projection numbers for 1 GeV/c pions from Fabrice Excel spread sheet, May 21,04

mis-hit probability formula, see
GhostTracks.mcd

Probability for background hit assignment error

MVD outer, integrated background

MVD inner, integrated background

MVD outer, central collision Au+Au

MVD inner, central collision Au+Au

Check that convoluted function for hit density per area gives the right number of particles by integrating over the surface of a long tube

OK, expected to be roughly the same, but smaller radius extends to higher h for a give z. The numbers are large because large h are included and we have used the incorrect distribution of constant dN/dh