icecube-gen2: the next generation neutrino …
TRANSCRIPT
ICECUBE-GEN2: THE NEXT GENERATION NEUTRINO
OBSERVATORY IN ANTARCTICA
Lu Lu for IceCube Gen2
Collaboration
Chiba University
Wilkinson Microwave
Anisotropy ProbeROSAT
CMB pair-production
NEUTRINOS: A NEW ERA FOR ASTRONOMY
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Hubble
FermiHAWC
IceCube
Pierre Auger
Telescope Array
GW
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WHY DO WE NEED GEN2 (HIGH ENERGY EXTENSION)The big picture:
Identify the sources responsible for high energy neutrinos seen by IceCube.
Extend diffuse spectrum to higher energy → connection with UHECR?
Neutrino flavour ratio and its indication of the source properties
Observation of Glashow resonance and tau neutrino
Cosmogenic neutrinos
…
Also:
Hadronic interaction models, cosmic-ray composition, charm production, exotic searches, PeV photons, high PT muons, elasticity and cross-section measurements …
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SO WE NEED A LARGER VOLUME In-ice upgrade*:
• ~ 10,000 more optical sensors
• 5 – 10 km3 instrumented volume
• ~ 120 strings
Wish-list:
• sensors with directionality and more effective area
• smaller holes to reduce drilling cost
• a surface array to veto cosmic-ray background
Challenges:
• -45ºC, 10,000 psi, logistics
*this talk we only focus on high-energy array for in-ice upgrade4
Gen2 High-energy array
PINGU
(low-energy)
In-ice high-energy array | surface veto array | ARA
GEOMETRY OPTIMISATION
# Strings 120
DOMs / String 80
String Length 1.3 km
Not yet decided, various types
Example geometry: “sunflower” with different string spacing
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200 m 240 m 300 m
In-ice high-energy array | surface veto array | ARA
DESIGNS FOR IN-ICE SENSORS
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• More sparse string spacing → sensors need to have larger effective area (Cherenkov UV photons)
• Benefits veto, event reconstruction
• For > PeV neutrinos we should have PMTs looking up since down-going is favoured due to earth absorption
IceCube DOM mDOM D-Egg WOMLOM
35 cm 36 cm 30 cm 11 cm 13 cm
Time delay
Time delay
Why new
sensors?
Directional information
Helps with reco
Simulation
down PMT
Simulation
upper PMT
Ch
arg
e
Hypo Anti-hypo
Example
200 TeV in sunflower 240 m
Down-going cascade
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PHYSICS CASE I: POINT SOURCE SENSITIVITY
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New sensor?
Current IceCube limit:
Markarian 421, 122 Mpc
δ= +38.21°
Discovery potential
PHYSICS CASE II: HIDDEN FEATURES IN THE DIFFUSE NEUTRINO SPECTRUM?
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Is there a connection
to UHECR?
Lars Mohrmann, phd thesis
?
Contained cascades and through-going
muons: events per year breaking down by
energy assuming E-2.13 spectrum
GEN2 WILL TELL US HOW DOES THE SPECTRUM GO
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Flavour dependent cut-off is an ultimate test for the source models
PHYSICS CASE III: FLAVOUR RATIO
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Glashow resonance boosts 6.3 PeV ഥν𝑒
π− → µ− + νµ 0: 1: 0
µ− → 𝑒− + ഥν𝑒+ νµ 1: 2: 0
𝑝 + 𝑝 → 𝑛π∓,0 + 𝑝 + 𝑝
ν𝑒νµ
synchrotron loss time < decay time,
muon loses energy before decay
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Muon damped
0:1:0 → 4:7:7
Neutron decay
π decay 1:2:0 → 1:1:1FLAVOUR RATIO
energy and flavour
dependent cut-off
Potentially to add
τ identification
1:0:0
https://en.wikipedia.org/wiki/Ternary_plot
30 years of Gen2, contours show 68% and 90%
SURFACE UPGRADESurface (75 km2 veto array) :
Icetop
Scintillators
Cherenkov telescope
Gary Binder
Surviva
l pro
ba
bility
Neutrino energy [GeV]
> PeV
Cos(z
enith
)
In-ice high-energy array | surface veto array | ARA
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1
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IceActAir-Cherenkov telescope
STUDYING HADRONIC INTERACTIONS
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Ralph Engel
Only in-ice can measure!
UHECR COSMOGENIC →
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P. Allison et al. (The ARA collaboration) Phys. Rev. D 93, 082003http://www.southpolestation.com/
1000 km3 volume
In-ice high-energy array | surface veto array | ARA
Auger - 9 yr x 3
ARA 37 – 3 yr
IceCube- 2 yr
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ROAD MAP
SUMMARY
• The high energy extension of IceCube, Gen2 is under design
• New sensor R&D are on-going and maturing
• Gen2 will provide a new and unique view of the high-energy Universe
• Sources, source properties and connections with UHECR are to be discovered
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+ KIT
G e n t o o
BACKUP
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https://arxiv.org/abs/1609.04981v1
backup