arianna - a new concept for neutrino detection steve barwick, uc irvinemadison, aug. 2006 anita...
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ARIANNA - A New Concept for Neutrino Detection
Steve Barwick, UC Irvine Madison, Aug. 2006http://www.ps.uci.edu/~anita
ARIANNA Institutions: UCI, UCLA, UH, OSU,UCollege-London
The Energy Gap
There is a gap in the Energy response of current detectors between 1017-3x1018 eV
GA
P
ARIANNA is designed to span the gap
ARIANNA rates(6 month)
ESS Fe-only~40 few
(20,500 hrs)
Neutrino Cross-Section
] = 0.24 If Nev = 400If =0.5o
If =2GQRS
2 parameter fit:Normalizationcross-section
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
ARIANNA - 10 years
GQRS
ARIANNA Concept100 x 100 station array, ~1/2 Teraton
~300m
Ross Ice Shelf, Antarctica
Satellite Image of Victoria Land and Ross Ice Shelf
Ross Island
2
Dry Valleys
ARIANNA
south
Minna Bluff
~150
km
30x30 km2
Ice Thickness ~500m
Reflected and Direct Events
ignore ice
Direct Reflected(much greater solid angle)
S. Barwick, 3rd NOVE Workshop (Venice, 2006)
Reflection loss: Ross Ice Shelf
150
Regions of smoother than normal ice-water interface
1 2
80
165180
77.8
2~0 dB
~0 dB1
C.S. Neal, J. Glaciology, 24(1979)295
south
Ross Ice Shelf
Reflection properties of the Ross Ice Shelf
150
12
80
165
180
77.8
2
~0 dB
1
1 2
south
Basal Smoothness of Ross Ice Shelffrom C.S. Neal, Ann. Glaciology 3(1982)216.
Location Surface RMS height (m)
77o25’S, 171o38’E
(good reflection coef)
84o24’S, 163o43’W
(known poor refl. coef)
0.03
0.10
60 MHz, 60ns radio echo pulse
Corroborating Evidence for Smooth Surfaces
from K. W. Nicholls, et al., Geophy. Res. Lett 33(2006)L08612.
<8mm!Flow trace
Sonar map of surface beneath Fimbul Ice Shelf
Conclusion: In regions outside of Flow Traces, surface variation is <8 mm!
Event Reconstruction
• Preliminary studies show that the radio path ambiguity (direct or reflected) is manageable.
– ~ 1 deg– E/E ~ 1
Detector Response• Simulations assume 100x100 square array, 300m separation, 500m
thick ice, all v-flavors(1:1:1), firn layer, 2 Quad-ridge horns per station, 3-station multiplicity, 2/4 channel@2.3Vrms, depth dependent attenuation, 3dB reflection loss, standard model
• Preliminary studies show that ARIANNA is sensitive over all angles.
Dir
ect
&
Reflect
ed
Reflectonly
ARIANNA Configurations
Configurations in Study1: 1-Quad, 1/2 chan2: 2-Quad, 2/4 chan3: 1-Quad, 1 dipole, 1/3 chan4: 5-Quad-closed, 2/10 chan5: 5-Quad-spread, 2/10 chan6: 5 -Quad-spread, 2/10 chan
1 station only
Base
line
Note: Channel threshold =2.3Vrms, 3 stations in Trig, unless otherwise stated
Ice Property Systematics
Index of refractionof firn ice
EffectiveAttenuationlength
Reflection Coef. Scattering fromIce-Water
ARIANNA Config. Systematics
Separation betweenstations Channel Threshold
Stations in Trigger
Channel Multiplicity
ARIANNA Advantages
• Near McMurdo, logistics manageable• Site likely has good reflection and absorption properties• Site protected from RF interference, and likely to stay that way• Borrow technologies from Auger, ANITA• Deployment straightforward and stations serviceable• Design relatively insensitive to many imprecisely known ice
properties (eg, localized patches of bad ice, strong scattering, reflection)
• Negligible environmental impact – stations removable when project ends
• 24/7/(365/2)
ProtostationBlock Diagram of Electronics
Outlook• With AMANDA-II, the requisite tools to
inaugurate multi-messenger astronomy are available -> IceCube continues this technique.
• To probe the neutrino fluxes and physics at highest energies, new techniques are being developed based on radio cherenkov detection.
• ANITA extends search volume to 106 km3
– McMurdo launch expected Dec 2006
• ARIANNA spans the impending energy gap – Awaiting further ice studies in Nov’ 06 (A-127M, if you want to
track our progress), and not the only contender (SALSA, superRICE, acoustic detection)
– Development continues at a feverish rate
ARIANNA Spec Sheet
• ~0.5 Teraton, 30km x 30km, 100x100 array• Resides on Ross Ice Shelf, near McMurdo• Angular Resolution <1 deg• 2 view of sky• Energy Resolution E/E ~ 1• Energy interval = 5x1017 eV -1020 eV• GZK Event Rate
~40 events/6 mo. (ESS)Few/6 mo if Fe only
Station Configurations
top
side2m
“2 Quad”
top
side
“5 Quad, Closed”
2m
5 Quad, Spread has 5m spacing
Block Diagram of ARIANNA Station Electronics
Ice Thickness Map for ARIANNA
McMurdo
ARIANNA
170 km50
km
50 k
m
1 2
south
QuickTime™ and aTIFF (LZW) decompressor
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Antarctic Traverse Route
Use part of traverse infrastructure to access ARIANNA?
Hillary Route - ‘57
UCI/UCLA Simulation Comparison
UCLA UCI
Direct: N>3 direct raysReflect: N>3 reflected rays
Combo: N<3 for both direct and ref.Both: N>3 direct, N>3 reflect
PHOTONS: not deflected, but: reprocessed in sources, absorbed in IR (100 TeV), and CBR
PROTONS: deflection in magnetic fields, GZK cutoff
NEUTRINOS: not absorbed or deflected, hard to see
AN
ITA
-GZ
K
~100sm
For GZK E
CCsm
(Anchordoqui, et al, hep-ph/0307228)
EHE Neutrinos Explore Higher EHE Neutrinos Explore Higher DimensionsDimensions
Ice transparency
• Loss tangent a strong function of temperature
• For cold ice, UHF (0.1-1GHz) best
• Antarctic data approaches pure ice values
L = [n (’’/’)] –1 ~ 6 km at 300 MHz & -60C (pure ice, theory)
Matsuoka et al. 1996
The Energy Gap and ARIANNA
[ Antarctic Ross Iceshelf ANtenna Neutrino Array ]
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