Hit Density Rates for MVD

Wieman 5/08/04
revised 5/13/04
revised 5/15/04

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

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. Improvements in luminosity are expected largely to be improvements in average, but RHIC II will have peak luminosity increases of 2-3 times the 15 kHz reported above.

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.

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

OK looks all right

central

min bias

One event hit density for silicon with central event

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.

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 of more than one hit in the tracking search window projected from SVT to MVD outer barrel.

Projection uncertainly from the SVT to the MVD outer barrel for 1.2 GeV/c pion, determined with GEANT tracking simulation, F. Retiere

To get 98% hit acceptance the search window should have a radius of 2.8 s, see
AcceptanceWindow.mcd

Area of the tracking window using 2.8 s radius

search window pileup probability for central collision

at MVD outer barrel

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

at MVD outer barrel

Probability of more than one hit in the tracking search window projected from MVD outer layer to MVD inner layer.

Projection uncertainly from MVD outer layer to inner layer 1.2 GeV/c pion, determined with GEANT tracking simulation, F. Retiere

To get 98% hit acceptance the search window should have a radius of 2.8 s, see
AcceptanceWindow.mcd

Area of the tracking window using 2.8 s radius

search window pileup probability for central collision

at MVD inner barrel

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

at MVD inner barrel

Proabability for in correctly associating a bacground hit with the track

projection numbers for 1 GeV/c pions from Fabrice Excell 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