MicroBooNE: LarSoft Simulation & PMT Response Tests

1. MicroBooNE: LarSoft Simulation & PMT Response Tests Jessica Esquivel August 6 2009 Nevis Labs, Columbia University

2. Mike Shaevitz Lesli Camilleri Willian Seligman Gary Cheng Outline/Acknowledgments • MicroBooNE Overview • SuperNova Neutrinos • Hardware • Software • Future Work/Conclusion

3. MicroBooNE Overview • Liquid Argon Time Projection Chamber • Booster neutrino beam • Neutrinos from the Main Injector(NuMi) • Primary Physics done is studying the low energy excess seen in MiniBooNE Published: “Unexplained Excess of Electron-Like Events from a 1 GeV  Beam”, PRL 102, 101802 (2009)

4.  gg e+e- MicroBooNE Overview

5. Induction planes U V Collection plane Y Electrons MicroBooNE Overview • Ionization electrons drift to 3 recording planes • 2 Induction planes U, V: +- 60 to vertical • 1 collection plane Y: vertical.

6. 8” PMT MicroBooNE Overview • Scintillation light is collected by PMT's • Used to determine the time when event occured • PMT's are coated with a Tetraphenyl-butadiene (TPB) to shift the scintillated light to visible light.

7. Super Nova Neutrinos • Neutrino Signal is the first to emerge from a Supernova. • Can give information about the early stages of core collapse • All Large LArTPC's should have the capability of collecting supernova neutrino data. • MicroBooNE is the beginning of large scale LArTPC's • Cold Electronics will reduce electric noise • LAr purity for longer drifts

8. MicroBooNE Overview

9. 22.5° 0° 45° 67.5° 90° Hardware: PMT point response • First tests tested the point dependency on the PMT.

10. Hardware: PMT point response • Poor Correlation • Unsteady Pulse Generator

11. Hardware: PMT response as a function of angle

12. Hardware: Calculated vs Experimented • Fresnel's Equations shown below were used as a checkpoint calculations to make sure the data that was being collected was close to the calculated data.

13. Hardware: Angle of Incidence Vs Relative Mean • Plot shows the calculated mean using Fresnel's Equations plus the data collected at three different points on the PMT

14. Hardware: Angle of Incidence Vs. Relative Mean • Discrepancies calculated and measured data include: • Human error in measuring the angle of incidence. • 2.65% on average over all the points • 6.6% at point A • 1.45% at point D • 1.3% at point G • Index of refraction of PMT was unknown, 1.5 was used for calculating purposes instead.

15. Hardware: Photodetector response in electrostatic field • In the MicroBooNE experiment, the PMT’s will be exposed to an electric field of 500V/50cm • We are recreating this by building a blackbox with two aluminum plates mounted 50cm away.

16. Pulser Ground (Cryostat) Oscilloscope +500V (Mesh)‏ LED 16 50 cm Hardware: PMT E-Field Results • Turning on the +500V has no effect on the PMT pulse height • 500V was then increased to 700V • Still no effect • The cathode is grounded Therefore all outside field lines terminate on it. • It acts as a Faraday cage • PMT was also reversed • Still no effect: There is an electrostatic shield

17. Software • The LArSoft software package has been run for NUE-e interactions with incoming energies of: • 50MeV • 100MeV • 150MeV • The reason why LarSoft was run for such low energies was to be able to simulate supernova neutrinos which happen on a low energy scale.

18. Software: Event Display • All events were shown in this form. • To extract information, a program was needed.

19. Software • Histograms have been created for: • Incoming Neutrino/Anti-Neutrino Energy • Outgoing Lepton Energy • Outgoing Neutrino/Anti-Neutrino Energy • Theta between the Incoming Neutrino Vector and Outgoing Lepton Vector • Number of Voxels relative to the incoming Energy • Number of Voxels vs the Energy of Electrons

20. Software

21. Software

22. Software

23. Software • Neutrinos are left-handed and electrons are as well. • Before colision, the angular momentum is zero. • Direction isn't important after collision because in any direction, angular momentum will be conserved. • This results in a flat neutrino energy distribution

24. Software • Anti-Neutrinos are right-handed • Before Colision angular momentum is +1. • Direction is important because angular momentum needs to be conserved. • Anti-neutrinos must emerge in the forward direction in the center of mass • This results in a peaked energy distribution.

25. Software: Theta between Neutrino and lepton Mean Theta in Degrees is:13.32 degrees

26. Software: Voxel • A Voxel is a 3D pixel that divides the energy deposited in the Liquid Argon into X, Y and Z cubes • These voxels are then what drifts to the simulated wire chambers.

27. Software Energy: 50MeV Mean: 57.04 Energy: 100MeV Mean: 115.6 Energy: 150MeV Mean: 172.6

28. Software • Plot shows the correlation between the Number of Voxels and the Energy of an Outgoing Electron

29. Future Work • Understanding why some events are thrown out. • Plot the electrons coming from an NUEbar-e interaction separately from a NUE-e interaction. • Plot Energy of Voxels vs Energy of Electron • Do PMT response tests on the PMT being used in MicroBooNE • Using a more sophisticated setup to reduce human error