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Estimation of rates and backgrounds

There are several different parameterizations for $e^-$, $\pi$ and $e^+$ simulations. However, they include different mechanisms so give different yields at the kinematics of E99-117. Test runs have been done in August 2000, the result ($e/\pi $, $e^+/e^-$ ratios and cross sections) have been compared to simulations and the best parameterization has been choosed for the simulation of E99-117. For details please refer to Appendix A.

With average beam current 15$\mu A$, polarization 80%, target polarization 40%, spectrometer momentum acceptance $\frac{\Delta p}{p} = \pm 4.0\%$ and solid angle acceptance 4.9 msr with open collimater (or 3.9 msr with 6 msr collimator) , the rates have been estimated by whitlow's fit. $e/\pi $ and $e^+/e^-$ ratios have also been estimated and are shown in Table 5.



Table 2: Simulation of rates and $e/\pi $, $e^+/e^-$ ratios for E99-117
kine # $x$ $(\frac{\mathrm{d}^2\sigma}{\mathrm{d}\Omega\mathrm{d}E'}\big)_{e^-}$ rate $\pi^-/e^-$ $e^+/e^-$
    (nb/GeV-sr) (s$^{-1}$)    
1 0.610 0.8749 0.1410 $\sim$10 $\sim$ 0.2%
2 0.475 4.0528 0.9522 $\sim$20 $\sim$ 0.5%
3 0.331 7.1019 1.2805 $\sim$100 $\sim$ 3%


next up previous contents
Next: Run time optimization Up: Kinematics, Rates and Schedule Previous: Kinematics   Contents
Xiaochao Zheng 2001-06-09