MC simulations for the project of FCC-ee Compton beam polarimeter.
The method is discussed in the publication https://arxiv.org/abs/1803.09595.
Tested with python 3.85 [GCC 9.3.0] and ROOT 6.22/03 on Linux Mint kernel 5.4.0-58-generic
- Simulation parameters may be altered in the hardware.py.
- Use mc-compton.py for Monte-Carlo generation of photon and electron distributions.
- The result will be saved to a root file with a name, similar to Sun Dec 13 10:49:17 2020.root.
- For fitting, alter the filename in eFit.py (somewhere around 140 line) and run the script.
- Bear in mind that the fitting procedure is quite long at this stage.
On my Intel(R) Core(TM) i3-6100U CPU @ 2.30GHz laptop the fit (with default parameter set) converges after 197 iterations, which takes
Real Time = 4115.06 seconds Cpu Time = 4122.41 seconds.
If this method is ever used, the fitting procedure should definitely be improved.
The fit result with default settings is:
FCN=6447.49 FROM MIGRAD STATUS=CONVERGED 208 CALLS 209 TOTAL EDM=2.08144e-09 STRATEGY= 1 ERROR MATRIX UNCERTAINTY 0.8 per cent EXT PARAMETER PARABOLIC MINOS ERRORS NO. NAME VALUE ERROR NEGATIVE POSITIVE 1 X_{0} 1.15679e-02 1.00231e-02 2 X_{1} 3.47635e+02 3.26152e-03 3 Y_{0} -1.06824e+00 4.15379e-05 4 Y_{1} 1.06820e+00 4.07565e-05 5 #kappa 1.62800e+00 fixed 6 P_{#parallel} 0.00000e+00 fixed 7 P_{#perp} 1.02652e-01 1.65003e-03 8 #sigma_{x} 1.96462e-01 4.54456e-03 9 #sigma_{y} 2.36739e-02 2.45517e-05 10 norm 5.22868e+07 1.41892e+04 Chi2: 6447.487180 NDF: 6119 Probability: 0.001729 A = 347.6238 +/- 0.0105 (0.00003) 1.627839909428406 0.00012432482133096817 E = 45.59708 +/- 0.00348