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Efficiency and Sensitivity for the HALO Detector

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Efficiency and Sensitivity for the HALO Detector

Cara Esposito

Saint Joseph’s University

Dr. Kate Scholberg

Duke University

- Brief background on neutrinos, supernovae, and the HALO detector
- Efficiency and the important information gained from examining the efficiency
- Sensitivity for HALO
- Summary

- The Equation above is for the probability of detecting flavor g at L for a two flavor case.
- Although there are three flavors, the Δm2 remains
- Normal Mass Hierarchy (NMH) has one heavy and two light mass states, while IMH has two heavy and one light mass state

Before

After

- Supernovae happen when a massive star can no longer sustain itself and it explodes
- 99% of the energy of core collapse supernovae is neutrinos

- SNOLab in Canada
- 79 tons of lead
- 128 helium detectors
- 2 km underground
- HALO 2 is currently in the developing phase and will most likely use 1 kiloton of lead

Lead

Helium Detectors

- Visualization of the simulation using Geant4

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- The left panel is for inverted mass hierarchy
- The right panel is for normal mass hierarchy

- From the energy deposited in the detector we can determine whether it’s a 1N or a 2N event.

1N

2n

- From the energy deposited in the detector we can determine whether it’s a 1N or a 2N event.

- Tells us how well the detector works

- HALO 1’s sensitivity for 5kpc supernovae
- Contours in which ninety percent of the number of one-neutron and two-neutron events fall
- The different colored curves correspond to different spectral parameters

- For 10 kpc supernovae HALO 1 can only constrain extreme models

- HALO 2 ‘s discriminatory power will increase with a greater number of counts for 10 kpc supernovae.

- Simulated neutron events in the HALO Geant4 simulator
- Efficiency for 1N events is approximately 36%
- Efficiency for 2N events is approximately 56%
- HALO 1 has good sensitivity for 5 kpc supernovae, but can only constrain extreme models for 10 kpc supernovae
- HALO 2 the larger the number of counts, the greater the yield for the discriminatory power

- K.Scholberg, C.Walter, A.Himmel, Duke University High Energy Physics Neutrino Group
- Triangle Universities Nuclear Laboratory's Research Experience for Undergraduates
- Halo Collaboration/SNOLab