Transcript Efficiency and Sensitivity for the HALO Detector

Cara Esposito
Saint Joseph’s University
Dr. Kate Scholberg
Duke University
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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
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Supernovae happen
when a massive star
can no longer sustain
itself and it explodes
99% of the energy of
core collapse
supernovae is
neutrinos
Before
After
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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
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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
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From the
energy
deposited in
the detector
we can
determine
whether it’s a
1N or a 2N
event.
1N
2n
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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
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HALO 1’s sensitivity
for 5kpc supernovae
Contours in which
ninety percent of the
number of oneneutron and twoneutron events fall
The different colored
curves correspond to
different spectral
parameters
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For 10 kpc
supernovae HALO 1
can only constrain
extreme models
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HALO 2 ‘s
discriminatory power
will increase with a
greater number of
counts for 10 kpc
supernovae.
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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
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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