Using the beam telescope and test beam infrastructure of DESY the material budget can be imaged: By integrating a material in the telescope, collecting data and reconstructing the scattering angle, the sample under test (SUT) can be 2D imaged in terms of position-dependent scattering angles. Furthermore, by using known material and one method radiation lengths - or the figure of merit thickness over radiation length (x/X0) - can be calibrated and used for unknown samples.
In November 2017 a first meeting happened with people working on these studies. The agenda and the contributions you find here: https://indico.desy.de/indico/event/18907/overview Participants of this first little workshop were: Jan-Hendrik Arling (DESY, ATLAS), Jan Dreyling-Eschweiler (DESY, ATLAS), Hendrik Jansen (DESY, CMS), Claus Kleinworth (DESY, CMS), Michaela Queitsch-Maitland (DESY, ATLAS), Benjamin Schwenker (University Goettingen, BelleII), Paul Schütze (DESY, CMS), Ulf Stolzenberg (University Goettingen, BelleII), Mengqing Wu (DESY, FLC).
First common goals of this "working collaboration" are:
- Provide an easy usage to get material budget images
- Compare and investigate different approaches and methods
- Providing calibration data and framework for more precise tracking
If you are interested to contribute, please contact us.
Example from ATLAS ITK, M. Queitsch-Maitland
Example from 3D-Tomography and https://desycloud.desy.de/index.php/s/fNMvKhVy9MmKn2U, P. Schütze
Caution: All below is under construction!
Step 1: Taking data
These is a brief summary out of experience.
- Define your telescope geometry
- coarsely adopt to thickness (range) of sample
- geometry and beam energy stay fixed for all runs
- alignment run: no sample
- calibration run: known material and thickness
- sample run
- Measurement settings and time:
- high energy and high rate, for example 4 GeV
- collimator settings
- ~5 tracks per plane
- ~1-2 kHz trigger rate
- for analysis >1000 tracks per image cell to achieve a proper resolution
Step 2: Track and scattering angle reconstruction
Kalman filter approach.
- install CLHEP: https://gitlab.cern.ch/CLHEP/CLHEP
- install/download ROOT: https://root.cern.ch/
- install TBSW: https://bitbucket.org/BenjaminSchwenker/tbsw
- adjust install.sh
to be continued