hi,
i just did a small mc study of the resolution from the current fast
fitter (does an analytic circle fit). i used run
$ANALDIR/v3_1/flr/flr-10175.root, which was generated with 200mu wire
resolution along with multiple scattering, and energy loss. for
600MeV<p<1GeV, i got a momentum resolution of 38MeV. this is without
wang's improvements of splicing two circles together with radii
proportional to the radius of the field in each region.
--chris
root [17] flr->Draw("pfl-pml","pwl>.6&&pwl<1")
(Int_t)572
root [18] FCN=707.781 FROM MIGRAD STATUS=CONVERGED 83
CALLS 84 TOTAL
EDM=1.10731e-09 STRATEGY= 1 ERROR MATRIX
ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 Constant 8.41230e+00 4.31558e-01 4.57707e-03 8.37437e-05
2 Mean -7.84356e-02 1.59099e-03 2.06901e-05 1.80328e-02
3 Sigma 3.79843e-02 1.12503e-03 8.37677e-05 5.53723e-03
(note that there is also an offset that can be corrected for.)
> +200mu assuming 200mu in x_i resolution
> +obtained resolutions:
> LIN QUAD CUB BLASTMC CUBCUB +200mu
> p/MeV 160 87 67 30 8 30
> h/mr 32 12 5 8 0.6 4.8
> f/mr 15 3 2 12 0.4 2.3
> z/mm 24 9 3.5 10 0.5 4.5
>
>
>
>
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