For any questions, please contact us: fengc@stanford.edu, vcairo@slac.stanford.edu, young@slac.stanford.edu
The package is written in Python 3.6.8
To run it in Jupyter Notebook: %run trackingerror.py
For instructions of using the code in a notebook, see 'example.ipynb'.
To run the package in terminal:
python3 trackingerror.py [-h] [-f filename] [-p momentum] [-m mass] [-B MagneticField][-eta pseudorapidity][-verbose v]
e.g. in terminal run: python3 trackingerror.py -f example.txt
To see the help: python3 trackingerror.py -h
The supported layer configuration is solenoidal geometry (i.e. cylinder layers), with origin set at its center. xy plane denotes the transeverse plane. z-direction is in the direction of the cylinder axis. All layers are assumed to be infinite long along z-axis. Particle is assumed to be of unit charge e.
The units of output are:
sigma(pt)/pt: no unit
sigma(d): micrometer
sigma(phi): radians
sigma(z): micrometer
sigma(theta): radians
About the input file: The "-f" option allows you to read from the detector configuration from a txt file, but the file must be in certain format:
To comment out a line use "#".
Each line is a layer configuration.
The first column is the layer width (unit: radiation length X0).
The second column is the detector resoluton in xy plane (unit: meter).
The third column is the detector resolution in z direction (unit: meter).
The final column is the layer position in the radial direction with respect to the origin (unit: meter).
The order of the lines does not matter, but two layers with the same position must be avoided.
An example of input file format can be found in example.txt. This is just a placeholder with material thickness set at 0, equally spaced layers and same detector resolution in the longitudinal and radial directions.
To change parameters from command line:
-m M, --m M mass of the particle in GeV/c^2 (default: muon mass)
-B B, --B B magnetic field in T (default: 2T)
-eta ETA, --eta ETA pseudorapidity (default: 0)
-p P, --p P momentum of the particle in GeV/c (default: 1 GeV) (Note this is the total momentum)
Caveat: at least three layers are needed for a reasonable output.