Eic Root software framework Alexander Kiselev EIC Software

Eic. Root software framework Alexander Kiselev EIC Software Meeting Jefferson Lab September, 24 2015 Brookhaven Lab July, 10 2019

Eic. Root framework building blocks n Panda. Root “Ideal” track finder, Interface to Gen. Fit … n n n Interface to GEANT, ROOT, … Fair. Base n MC generated evts import Fast smearing codes n TPC R&D stuff, … n Eic. Root Cbm. Root eic-smear n Fopi. Root n solenoid modeling RICH stuff IR design configuration ROOT-based I/O, VGM, VMC (e. g. easy switch between G 3 & G 4)

End user view n No executable (steering through ROOT macro scripts) simulation digitization reconstruction PID; assembly -> MC points -> Hits -> Tracks, clusters -> Events n n ROOT files for analysis available after each step C++ class structure is well defined at each I/O stage

Geometry description n Input formats: n ROOT TGeo (with mapping) GEANT GDML Old HADES. geo files n CAD design drawings (. stp, . stl) n n n Output format: n STAR TGeo Be. AST TGeo ROOT TGeo (geometry modules used for a particular simulation run are assembled on-the-fly into a TGeo. Manager instance and written out into the output simulation. root file used by digitization and reconstruction)

Typical applications § Physics analysis (? ) § Test beam data analysis § R&D studies § Tracking § Calorimetry § RICH simulations (Fopi. Root codes adapted) § TPC modeling (Cbm. Root codes adapted) q Lately: e. RHIC IR design

e. RHIC model detector layout (2015)(hermetic coverage) -4<h<4: Tracking & e/m Calorimetry hadronic calorimeters SBS e/m calorimeters RICH detectors 9. 0 m CBM EIC R&D (UCLA, BNL) ons tr elec EIC R&D (UCLA, BNL) ALICE rons had silicon trackers TPC GEM trackers 3 T solenoid coils

e. RHIC model detector layout (2018) 3 T solenoid cryostat coils iron yoke hadro ons electr ns 0 m u hadronic calorimeters e/m calorimeters RICH detectors 9. o t p silicon trackers GEM trackers TPC

Examples of geometry building blocks Q 2 E B 0 Si tracker ~7 20 mrad vacuum pipe 5 c m p B 0 vacuum chamber exit window GEMs HCal Em. Cal m. Vertex

Example case studies 12 Ge. V pions: Hcal vs Em. Calorimeter design optimization Tracker momentum resolution slope ~1. 20 DIS electron reconstruction Roman Pot acceptance Neutron fluence 100 x 10 Ge. V first quad aperture & beam pipe RP B 0

EIC smearing generator interface MC generator ASCII output Tree code: Build ROOT tree containing events PYTHIA DPMJet PEPSI Milou gmc_trans Rapgap LEPTO Djangoh n Smearer: Perform fast detector smearing Large number of EIC Monte Carlo generators with standard ASCII format Both event import and smearing functionality is supported in Eic. Root

Calorimeter code implementation n Written from scratch (use ideas rather than codes) n n ATLAS fast simulation (“frozen” showers) CMS topological cluster search Unified interface (geometry definition, digitization, clustering) for all EIC calorimeter types Rather detailed digitization: n n n configurable light yield exponential decay time; light collection in a time window attenuation length; possible light reflection on one “cell” end Si. PM dark counting rate; APD gain, ENF, ENC configurable thresholds

Calorimetry “designer” tools § As long as the following is true: n n your dream calorimeter is a logical 2 D matrix … … composed of “long cells” as elementary units, all the game is based on (known) light output per energy deposit, energy resolution after “ideal” digitization suffices as a result § … one can with a moderate effort (99% of which is writing a ROOT C macro with geometry and mapping description) build custom Eic. Root-friendly calorimeter which can be used for both standalone resolution studies and/or as an optional EIC device (and internal cell structure does not matter) -> see examples/calorimetry directory for details

STAR Em. Cal upgrade simulations 3 degree track-to-tower-axis incident angle n n “Exact” geometry description “Realistic” digitization stands for: 40 MHz Si. PM noise in 50 ns gate; 4 m attenuation length; 5 pixel single tower threshold; 70% light reflection on upstream fiber end; -> good agreement with original MC studies and measured data

STAR HCal upgrade simulations 12 Ge. V pions: Hcal vs Em. Cal - GEANT 4, FTFP_BERT physics list - Birk’s correction accounted by hand slope ~1. 20 -energy resolution comparable to ZEUS 1987 paper HCal Em. Cal

Tracking code implementation n Large parts of other experiment’s codes adapted: n n n Panda. Root: “ideal” track finder, Gen. Fit fitter, etc Fopi. Root: TPC digitization, realistic track finders (Hough transform; Riemann sphere fit), Gen. Fit fitter, RAVE vertex builder, etc HERMES: linearized Kalman filter forward spectrometers Kalman filter fit quality for two “extreme” track configurations <ndf> = 206 <ndf> = 9 1 Ge. V/c p+ tracks at h=0. 5: 32 Ge. V/c p+ tracks at h=3. 0:

Feature list & restrictions § Modularity and flexibility in geometry description § Several detector templates available in digitization: § Flat 1 D (strip) and 2 D (pixel) sensors; gaussian and sqrt(12) smearing § Flat 2 D {r, f} sensors (endcap-like) § Volume 3 D (TPC-like) § Volume 1+2 D (axial symmetric along the track) § Kalman filter fitting through all hits at once (via Gen. Fit)

Feature list & restrictions § Only ROOT TGeo geometry is supported § Mapping information should be bundled in the same ROOT files with TGeo geometry description and it is directly available for digitization and reconstruction codes (so for each MC hit the information about physical volume it belongs to - shape, 3 D transformation, etc - can be polled on-the-fly at any time) § “Ideal” (known a-priori) hit-to-track association

Example R&D study: vertex+barrel tracker Consider vertex tracker + TPC in 3 T field; shoot 10 Ge. V/c pions at q=75 o -> see examples/tracking/config. 2 directory for details § Once Docker image is downloaded it takes <5 minutes to generate this plot

Eic. Root via Docker container Momentum resolution Calorimeters by Hakan Wennloef

Eic. Root via Docker container Momentum resolution Vertex Layers Calorimeters by Matt Posik

Eic. Root via Docker container Impact of the outer forward GEM detectors on seeding the RICH ring Momentum resolution reconstruction in Be. AST geometry Momentum Resolution vs. Theta (10 Ge. V Pions) 6 Width (Sigma) of (preco-pgen)/pgen [%] n 5 No outer GEMs Outer forward GEMs 4 With Outer GEMs 3 2 1 Momentum resolution 0 0 10 20 30 40 Angle of Deviation from Beam Pipe (degrees) TPC Momentum Resolution vs. Particle Momentum (Pions, Theta = 15. 41 0) Width (Sigma) of (preco-pgen)/pgen [%] 7 Ve No Outer GEMs 6 5 Inner forward GEMs x rte RICH r cto te de Si tracker With Outer GEMs 4 3 2 Calorimeters 1 0 0 20 40 Momentum (Ge. V/c) 60 80 by Matt Bomberger

Take away message § Eic. Root can be used “as is” for standalone R&D studies § Several ready-to-go examples exist Git § Codes available for download from BNL SVN server q. . . as well as in Docker container image(s) q . . . and can seemingly be incorporated in a more generic packaging scheme if needed