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

2 Outline/Acknowledgments Mike Shaevitz Lesli Camilleri Willian Seligman Gary Cheng 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, (2009)

4 MicroBooNE Overview   e + e -

5 MicroBooNE Overview Ionization electrons drift to 3 recording planes – 2 Induction planes U, V: to vertical – 1 collection plane Y: vertical. Electro ns Induction planes U V Induction planes U V Collection plane Y

6 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. 8” PMT

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

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 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 16 LED Pulser Oscilloscope +500V (Mesh)‏ 50 cm Ground (Cryostat)

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: 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: Energy: 100MeV Mean: Energy: 150MeVMean: 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