1kt reconstruction tools on G4 output Comparison with fwdetsim

1kt reconstruction tools on G4 output Comparison with fwdetsim Maximilien Fechner (Saclay) in collaboration with S. Mine (UCI) • While at UCI : geometry library, Qmaps, … • Ktafit & ktafit 2 • polfit M. Fechner, 2km-meeting

Geometry issues • In order to use 1kt software, the « 1kt » geant4 setting must be used PMT numbering is still completely different (affects gexyz, geoset, neighbsk,…) • Therefore : libgeom.kt, libsklib.kt must be modified ( all 1kt programs expect specific common blocks to be filled) • Use « geofile.txt », and rewrite neighbsk M. Fechner, 2km-meeting

Standard 1kt PMT number Standard 2km PMT number M. Fechner, 2km-meeting

Comparison between geant4 and fwdetsim • In order to make sure both simulations agree : • I compare qmaps (amount of collected charge vs. PMT number) • time distributions (tisk) • total charge distributions (qismsk) • Nhit distributions (nqisk) • I generated 1000 500 MeV e- events, at the center of the detector in both geant4 • and fwdetsim_5.21 • The 2km tube numbers are converted to 1kt tube numbers M. Fechner, 2km-meeting

Qmaps 10000 fwdetsim 2000 Pmt number geant4 10000 Not enough hits on the endcaps 2000 2000 Geant4-fwdetsim -2000 M. Fechner, 2km-meeting

Effect of the different PMT numbering schemes on the qmap 1kt numbering 2km numbering M. Fechner, 2km-meeting

Tisk distribution fwdetsim, geant4 zoom ns ns I added a 960.0 ns offset to the PMT hit time in JHF2kmWCDigitizer.cc (otherwise Ktafit 1&2 crash), this value should be slightly lower M. Fechner, 2km-meeting

Nhit and total charge distributions Total charge in pe Number of hit pmts Too few PMTs are hit in JHF2km qisk M. Fechner, 2km-meeting

Ktafit comparison • 1000 e- @ 500 MeV were generated using fwdetsim and JHF2km • Reconstructed using ktafit (with the proper geometry corrections) : vertex fit and initial ring direction only M. Fechner, 2km-meeting

fwdetsim, geant4 Position Direction The precision on the vertex is twice as bad for geant4 M. Fechner, 2km-meeting

Ktafit2 for Geant4 • 1000 e- events @ 500 MeV in JHF2km reconstructed using ktafit+ktafit2 • Same thing for µ- • Not enough time to apply ktafit2 to the fwdetsim samples… • Energy seems OK but PID is wrong (should be <0 for e-) muons, e-

ktpolfit • 1000 pi0 @ 500 MeV • 1000 e- @ 500 MeV • Comparison of Dlikelihood and invariant masses • Using gamma MCtrue information as input • At the moment these comparisons are qualitative M. Fechner, 2km-meeting

200 MeV 200 MeV 100 MeV 100 MeV Invariant mass distributions Wide fit and forward fit For electrons Invariant mass distributions Wide fit and forward fit For Pi0 M. Fechner, 2km-meeting

Ktpolfit works ! M. Fechner, 2km-meeting

Summary • After modification of libgeom.kt and libsklib.kt (+include files) the 1kt reconstruction programs can successfully process JHF2km | root2zbs output • But the reconstruction is worse than with standard 1kt MC samples • JHF2km needs tuning : reflection and scattering ? • Katfit, ktafit2 probably require additional modifications • Ktpolfit improvement under way… M. Fechner, 2km-meeting

1kt reconstruction tools on G4 output Comparison with fwdetsim