1. The LiC Detector Toy (LDT) Tracking detector optimization with fast simulation VERTEX 2011, Rust M. Valentan, R. Frühwirth, M. Regler, M. Mitaroff

2. LiC Detector Toy (LDT) In a nutshell The “LiC Detector Toy” (short “LDT”) allows investigation of the track parameter resolution via Monte Carlo, for optimizing a detector setup Simulation of particle tracks through the track sensitive part of a collider detector with a solenoid magnetic field, including material effects Support of measurements by semiconductor pixel and strip detectors, and a TPC Track reconstruction by a Kalman filter, including tests of goodness of the fits Written in MatLab ® (a language and IDE by MathWorks) Version 2.0 available for GNU Octave June 22, 20112M. Valentan (HEPHY Vienna)

3. LiC Detector Toy (LDT) Motivation Compare track parameter resolutions of various detector setups, for both barrel and forward/backward regions Optimize size and position of the track sensitive devices, and of the detector material budgets A simple tool – easy to understand, handle and modify Can easily be adapted to meet individual needs Can be installed on a desktop or laptop PC Quick results by “shorter than a coffee break” Ideal tool for investigating the effect of local variations June 22, 20113M. Valentan (HEPHY Vienna)

4. LiC Detector Toy (LDT) Single or double Si strip layers, pixel layers, TPC Passive material possible Homogeneous magnetic field (by a solenoid), rotational symmetry w.r.t. the z-axis of the detector setup Start parameters for simulated tracks are user- defined: –Vertex position range,transverse momentum range, range of polar angle θ, number of tracks from the vertex. –Latest custom version reads start parameter from file Output: –Track parameter resolutions –Impact parameter resolutions –Test quantities June 22, 20114M. Valentan (HEPHY Vienna) General features

5. LiC Detector Toy (LDT) Graphic User Interface (GUI) Choose and display detector geometry View output Simulation parameters Save and load results June 22, 20115M. Valentan (HEPHY Vienna)

6. LiC Detector Toy (LDT) Detector model Human readable text file Coaxial cylinder layers of arbitrary length and position Circular plane layers, perpendicular to z-axis Passive layers 2D measurement –Barrel: RΦ and z –Forward: u and v Resolution in TPC may depend on z. x v δ1δ1 y δ2δ2 June 22, 20116M. Valentan (HEPHY Vienna)

7. LiC Detector Toy (LDT) 2D and 3D Detector Display June 22, 20117M. Valentan (HEPHY Vienna)

8. LiC Detector Toy (LDT) Exact helix track model Data corruption by measurement errors, multiple scattering and detector inefficiencies only Gaussian (e.g. for TPC) or uniformly distributed measurement errors Material budget assumed to be concentrated in “thin” layers, no special treatment of electrons: –Multiple scattering: |p| conserved, correct path length traversed; –Thickness of scatterers given in radiation lengths; –Scattering angles Gaussian distributed (Rossi-Greisen-Highland’s formula); –No energy loss (by ionisation or bremsstrahlung) simulated. June 22, 20118M. Valentan (HEPHY Vienna) Track simulation

9. LiC Detector Toy (LDT) Complex intermediate region Arbitrary sequence of cylindric and plane detector layers June 22, 20119M. Valentan (HEPHY Vienna)

10. LiC Detector Toy (LDT) No pattern recognition Single track fit by an exact Kalman filter Linear track model: Expansion point is a “reference track” Fitted parameters defined at the inside of the innermost layer: –{ Φ, z, θ, β = φ-Φ, κ = ±1/r H } with sign(κ) = sign(dφ/ds), and corresponding 5x5 covariance matrix Goodness of the fit monitored by pull quantities and χ² June 22, 201110M. Valentan (HEPHY Vienna) Track reconstruction

11. LiC Detector Toy (LDT) Automatic loops Several pairs of barrel and forward detector setups Several different start values for e.g. the transverse momentum Compare detector setups as function of –momentum –polar angle June 22, 201111M. Valentan (HEPHY Vienna)

12. LiC Detector Toy (LDT) Automatic loops rms of Δp t /p t 2 σ of projected impact These plots are direct outputs of the program! blue: green: red: ILD ILD without SIT ILD without SET June 22, 201112M. Valentan (HEPHY Vienna)

13. LiC Detector Toy (LDT) Fine grained simulation mode Normal: –Simulate many tracks –track parameter resolution from distribution Quick & dirty: –simulate one track –track parameter resolutions from covariance matrix –enables fine scanning of detector setup 13M. Valentan (HEPHY Vienna)June 22, 2011 quite clean

14. LiC Detector Toy (LDT) LDT 2.0 for GNU Octave Octave is free Command line based (no GUI) All features except for 3D detector display Factor 10 slower June 22, 201114M. Valentan (HEPHY Vienna)

15. LiC Detector Toy (LDT) LDT and other software Successful validation against –Fullsim: Mokka/Marlin (ILD) –Fastsim: SGV (ILD) External list of start parameters –Instead of simulating internally –Connection with event generators Output as csv file for further analysis –Successfully tested with RAVE vertex fitting toolkit June 22, 201115M. Valentan (HEPHY Vienna)

16. LiC Detector Toy (LDT) Wishlist Conical detector surfaces –> e.g. slanted part of Belle II SVD Segmentation in RΦ –> Simulation of ladders Simulation of e - /e + energy loss by bremsstrahlung; Continuous multiple scattering (e.g. in front of muon detectors). 16M. Valentan (HEPHY Vienna)June 22, 2011

17. LiC Detector Toy (LDT) 17M. Valentan (HEPHY Vienna)June 22, 2011

18. LiC Detector Toy (LDT) Updated TPC resolution TPC resolution as commented by Ron Settles: Includes: –Constant point resolution of endplates –Term dependent on angle β between track and normal vector of detector layer –Term dependent on polar angle θ and charge spreading June 22, 201118M. Valentan (HEPHY Vienna)