ANITA: Hunting for Ultra-High Energy Neutrinos in Antarctica Ryan - - PowerPoint PPT Presentation
ANITA: Hunting for Ultra-High Energy Neutrinos in Antarctica Ryan Nichol Outline Timeline From Austria in 1912 to Antarctica in 2006/8 Motivation For Astronomers, Astrophysicists and Particle Physicists Detection
– From Austria in 1912 to Antarctica in 2006/8
– For Astronomers, Astrophysicists and Particle Physicists
– Problem of size – Askaryan effect
– Why Antarctica – Detector Concept – Results
2
3
Wolfgang Pauli does “something very bad”... he postulates the neutrino
Gurgen Askaryan hypothesises coherent radio emission from particle cascades in dielectric media
Wilson and Penzias discover the cosmic microwave background
Victor Hess discovers cosmic rays, by flying balloons up to 3 miles above Austria
4
Super-Kamiokande discover neutrinos have mass. Using neutrinos produced by cosmic rays in the atmosphere
Kamiokande, IMB and Baksan detect neutrinos from a nearby supernova
Greisen, Zatsepin & Kuzmin predict the end of the cosmic ray spectrum
ANITA-I launches from Williams Field in Antarctica
5
6
Radio Neutrinos? X-Ray Infrared Optical
!"#$%&'&%('%)*"+,-)." /&'01%(%&*'%+ 21-+#"3'0-+($4."*
The Particle
Neutrinos can probe the distances and energies that other particles can’t reach.
For Astronomers For Astrophysicsts
7
p + ϒCMB → Δ* → n + π+ ➘ µ+ + νµ ➘ e+ + νµ + νe
Auger 2007 ICRC Results
8
p
ν
50Mpc Radius
GZK Neutrinos Point Back to original proton source
– Large extra dimensions – Micro blackholes
– z=1 is v. long baseline
9
Large extra dimensions
Anchordoqui et al. Astro-ph/0307228
GZK !
Anchordoqui et al: hep-ph/0605086
Table from David Saltzberg
– Neutrino mass limits – Supernova mechanics – + lots more
10
10 20 30 40 50 60 70 80 90 100 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005
Annual Citations (from SPIRES) of SN 1987A Papers Plots stolen from Georg Raflett
11
~1 GZK neutrinos/km2/year @ 1018 eV the ν-N interaction length ̃ 300km ∴ 0.003 neutrino interactions/km3/year
12
– Mature field but not scalable to huge volumes
– Active field best candidate for first detection
– Emerging field, with much R&D
– Air showers
13 radio Cerenkov
Cerenkov acoustic
µ
incoming neutrino
Incoherent Coherent Coherent
– 20% Negative charge excess:
– Excess travelling with, v > c/n
– For λ > R emission is coherent, so P ∝ E2shower
14
e± or ϒ Typical Dimensions: L ≈ 10 m RMoliere ≈ 10 cm
– (like a big cat’s litter box)
15
11
From Saltzberg, Gorham, Walz et al PRL 2001
16
!20 !15 !10 !5 5 10 15 20 25 30 !3 !2 !1 1 2 time, ns reference volts !20 !15 !10 !5 5 10 15 20 25 30 !60 !40 !20 20 40 time, ns field strength, V/m/MHz raw RF Cherenkov partially deconvolved raw impulse response partially deconvolved
From PRL 99, 171101 (2007)
17
18
19
Honolulu, Hawaii, USA
Irvine, California, USA
Angeles Los Angeles, California, USA
London, UK
Newark, Delaware
Pasadena, California, USA
Lawrence, Kansas, USA
Minneapolis, Minnesota, USA
Columbus, Ohio, USA
Center Menlo Park, California, USA
Taipei, Taiwan
Louis
– Lots of Ice
– Also:
exclusively dedicated to scientific research
population – So relatively free of manmade noise
20
Ice depth data from BEDMAP consortium
– A balloon borne experiment
21
22
L1 - Antenna L2 - Cluster L3 - Global
– Just 0.02mm thick – Takes 100 million litres
hours) to fill
23
24
25
– Three and a half sort of polar orbits – Recorded over 8 million triggers
26
Fits inside the balloon at altitude
– Initiated by detonating small explosive to separate from balloon – Descend gently on a parachute to the ground – Release parachute to prevent dragging
dragged for 100 miles (ending up in a crevice)
was dropped from 5000 feet
27 Photos from Dana Braun
28
29
AB"F) A4)
107
Sum of x-corrs
Calibration pulse map
from A. Romero Wolf, Neutrino 2008
Cross-Correlated Waveforms
30
Broadband antenna Ross ice shelf 25 m
To Payload
Pulser
Reconstructed event locations ~150km 0.8 deg in Azimuth 0.2 deg in Elevation
31
“Camp” = any human-made installation, active or not
– 0 V-Pol (no Askaryan like neutrino signals) – 6 H-Pol
32
“Camp” = any human-made installation, active or not
– Only top of Cherenkov cone escapes TIR at surface – Fresnel coefficients transmit more V-pol than H-pol
– Radio signals from cosmic ray air shower
33
34 From PRL 103, 051103 (2009)
– Lower system temperature by ~40K
– Improve efficiency by ~20% (lower thresholds)
– Improve sensitivity by ~30%
– Improve sensitivity by ~30%
– Factor of 1.7 in threshold --> x3 in event rate – Up to 30% in exposure (flight path dependent) – Up to 40% in livetime – Total factor > 5 in neutrino event rate
35
– Better flight path – Over 27 million events – Over 100,000 Taylor Dome pulses
– Two students spent a week camping
36
37
38 Launch Termination Day ANITA-1
Antenna Noise Temp (K)
39
– ANITA-II payload is already as large as the launch vehicle can cope with – Possible augmentations include:
– Turn the balloon in to the detector – Create a reflective radio mirror inside the balloon focussing the radio pulses to a central feed array
40
– Deploy radio detectors around the IceCube experiment – Possibility to measure neutrino with all three detection methods simultaneously – Need large footprint to detect GZK neutrinos
41
– SalSA (Salt Dome)
42
1 2 3 4 5 6 7 Depth (km)
Antenna array
Rock salt can have extremely low RF loss
Frequency (GHz)
0.1 1
Field Attenuation Length (m)
10 100
LF Antennas, 50 ft. LF Antennas, 75 ft. Midband Antennas, 50 ft. Midband Antennas, 90 ft. HF Antennas, 50 ft. HF Antennas, 90 ft. Fit to Data 1/Frequency
43
44
– At least at 37km – Paint everything white
– Not too hot – Not too cold – Need half black half white
45 Thanks to the artists: Kai Smart, Dana Grant, Karen Joyce and ??? and Jeff Kowalski for the photographs
46
Date
– Second flight (December 2008) will start to constrain ‘standard’ GZK neutrino models.
– Probing fundamental physics at energies beyond the reach of terrestrial accelerators.
47
48
– 10 man weeks in a tent in the dry valleys – Waiting for the balloon to fly over
49
50
Taylor Dome
52
Pretty pictures from Hubble, Chandra (X-ray) and AAO
53
10 20 30 40 50 60 70 80 90 100 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005
Annual Citations (from SPIRES) of SN 1987A Papers Plots stolen from Georg Raflett
– AstronThe pretty pictures answer.
54
Radio Neutrinos? X-Ray Infrared Optical “The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.” Marcel Proust
– Infrared Background – CMB
– Deflected by magnetic fields – Attenuated by CMB
– Can reach the energies and distances that
55
!"#$%&'&%('%)*"+,-)." /&'01%(%&*'%+ 21-+#"3'0-+($4."*
The Particle
– Earth CR flux only – Injection Spectrum – Cosmological Evolution – Optical Density of Source
56
ν ν total
Engel, Seckel & Stanev
57
Sub-ns pulse, Ep-p~ 200 V/m!
simulated shower curve 2GHz data Reflection from side wall
100% polarized In proper plane
58
Coherent signal over 4 orders of magnitude SNR dominant for E > 10 TeV
– Attenuation length is greater than 1km – Limits set on the birefringence – Many GPR measurements also
59
– Uses Optical Cherenkov method
60
No excess above atmospheric neutrinos
61
62
Measure Time Difference Between Antennas Using Cross-Correlations Upper Lower
63
107
Sum of x-corrs
4x106
Sum of x-corrs
Calibration Signal Thermal Noise
64
!
! >2,*#!2,#*)02!?6/3!
3=07,"08!)*78**)2!,7!,2! "/22,@08!7/!38)2=68!7.8! A,68-7,/*!/?!)66,B)0!/?!6)A,/! "=028!7/!C&$:/!,*!808B)7,/*! )*A!CD$:/!,*!)E,3=7.! F@)28A!/*!<+GH<I0,78!
! H.8!*8=76,*/!A,68-7,/*!-)*!
B)6(!)6/=*A!6)A,/!"=028! A,68-7,/*!@=7!,2!-/*276),*8A! 7/!C%/!,*!808B)7,/*!)*A!@(! KI:/!,*!)E,3=7.!@(! "/0)6,E)7,/*!)*#08$
C%/ CL/
66
!
The observed voltage Vobs is proportional to the neutrino energy E!: y is the fraction of neutrino energy in the cascade heff is the effective height of the antenna (gain) R is the range to the cascade Gaussian in " from observer position on Cerenkov cone
(estimated from RF spectrum)
Exponential is attenuation in ice at depth d.
(estimated from RF spectrum and polarization effects) Gives: #$! / $
!~ 1.9 (60% of which is intrinsic from y)
2
"2
– ARIANNA (Ice Shelf) – SalSA (Salt Dome)
67
1 2 3 4 5 6 7 Depth (km)
Antenna array
Rock salt can have extremely low RF loss
Frequency (GHz)
0.1 1
Field Attenuation Length (m)
10 100
LF Antennas, 50 ft. LF Antennas, 75 ft. Midband Antennas, 50 ft. Midband Antennas, 90 ft. HF Antennas, 50 ft. HF Antennas, 90 ft. Fit to Data 1/Frequency
– Array of antennas on top of the Ross Ice shelf
– Advantages:
68
Ice shelf Reflected Ray Direct Ray
69
Better than 300m across the band
Preliminary
– “Call that an accelerator?”
we work out where it is, how it works and what exactly it is accelerating.
– “World’s largest scientific experiment?”
actually detected anything yet (but hey, neither have you).
– “Call that a long-baseline neutrino experiment?”
little blighters.
– “Yet more stuff that might happen before the ILC”
71
72
– Established 1937 – Takes its name from McMurdo Sound (named after Lieutenant Archibald McMurdo of the Terror – Near Scott’s Hut – Food is inedible 363 days a year
– Harbour (two weeks a year) – 3 Airfields – 1 bowling alley – 3 bars
73
– Own galley (so edible food) – Three payloads in 2006 – No indoor plumbing though
74