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Megaton Water Cherenkov Detectors and
Astrophysical Neutrinos
Maury Goodman, Argonne National Lab
September 2004 Now 2004; Maury Goodman
Megaton Water Detectors
1 Megaton = 1000 milli-Megaton
UNO (650 milli-Megaton) US Collaboration, focusing on Henderson Mine Frejus/CERN initiative
Hyper-Kamiokande (1000 milli-Megaton)
September 2004 Now 2004; Maury Goodman
Outline
AGN ’s “A Search for AGN ’s in Soudan 2”
[Astroparticle Physics 20 (2004) 533-547]
A taste of UNO & astrophysics Sources Supernova Relic ’s Shopping list of other possible sources of
astrophysical ’s
Status of Thousand-Milli-Megaton Water Cherenkov projects
September 2004 Now 2004; Maury Goodman
Search for AGN ’s in Soudan 2
September 2004 Now 2004; Maury Goodman
Soudan 2
♣ M = 1 milli-Megaton
♣ Very fine-grained iron calorimeter drift chamber built to study proton decay
♣ Use horizontal muons to identify neutrino induced sample
♣ Use energy loss to search for AGN ’s
September 2004 Now 2004; Maury Goodman
Horizontal muons are neutrino induced.
z > 82 o
Must take topography into account
Slant depth > 14kmwe Multiple scattering cut
September 2004 Now 2004; Maury Goodman
induced
Acceptance is 1.77 sr or 14% of 4
September 2004 Now 2004; Maury Goodman
N = 65; t = 2 108 s live; = .56; Aeff=87m2
() = 4.01 0.50 0.30 10-13 cm-2s-1sr-1
( E > 1.8 GeV)
The 65 events are presumably all atmospheric neutrinos. AGN neutrinos would presumably have added energy loss along the tracks
September 2004 Now 2004; Maury Goodman
Muon Energy Lossabove 1 TeV
1 TeV
Example of a horizontal muon in a 20m x 3m fine grained detector
September 2004 Now 2004; Maury Goodman
Expected energy loss in Soudan 2
No event had any visible catastrophic energy loss
Efficiency was calculated using a predetermined cut of 5 GeV
E(TeV) clCM-2SR-1S-1
5 60% 2.2 10-14
20 91 1.5
100 99 1.4
September 2004 Now 2004; Maury Goodman
Soudan 2 limits
September 2004 Now 2004; Maury Goodman
Search for AGN ’s in
Water Detectors
September 2004 Now 2004; Maury Goodman
Up-’s in Super-K
• For “SK-I”– 4/96 to 7/01
• 1680 live-days– More than other SK
analyses, this is insensitive to poor detector conditions
• For >7m path (>1.6 GeV):– 1901 thru-
• 354 are showering
– 468 stop-– <1.4o tracking res.
September 2004 Now 2004; Maury Goodman
UNO and UHE
Area matters for detecting up-going Take Super-K as baseline (50 milli MT)
Effective area ~1200m2 for entering events UNO is 13x SK’s volume (650 milli MT)
Only 5.5x the area, ~6600m2
Low background sensitivity will increase by 5.5Large background sensitivity will increase by 2.3
km3 detectors will be ~1,000,000m2
and are already under constructionUNO won’t compete for anything triggered by km3
September 2004 Now 2004; Maury Goodman
Lower Energies?
But long-string PMT detectors such as AMANDA, Antares, Baikal, etc. have very high Energy thresholds
UNO will have a ~5 MeV or ~10 MeV depending on final PMT density
Strategy would be similar to Soudan 2
September 2004 Now 2004; Maury Goodman
Astro Issues
(The next several slides courtesy Alec Habig) In searching for sources, previous
experiments have taken a hodge podge approach
Experience says: you look at noise in enough different ways, you will see surprising things! Needed-
A priori tests!! Blind analyses? (Avoids some penalties for trials.)
September 2004 Now 2004; Maury Goodman
Backgrounds
• Our background for source searches (and most all our data) are atmospheric
• Two approaches :– Bootstrap– Monte Carlo
September 2004 Now 2004; Maury Goodman
Bootstrap
• Take the observed events• Randomly re-assign directions and live times• Pros:
– Easily generates background which matches angular and live time distribution of real data
– Any astrophysical will be scrambled in RA and disappear from the background sample
• Cons:– For low statistics samples backgrounds are too granular,
introducing non-Poissonian effects– Trying to smear space or time to combat granularity
introduces different non-Poissonian effects
September 2004 Now 2004; Maury Goodman
Monte Carlo
• Use the experiment’s atmospheric Monte Carlo events, assigned times from the experimental live time distribution
• Pros:– Guaranteed to contain no point sources– Directly simulates your background
• Cons:– Only as good as your MC– More work to make, especially the live-time
distribution (given rates << clock ticks, need to save down-going CR distribution)
September 2004 Now 2004; Maury Goodman
All-sky survey
• Do we see anything anywhere sticking out over background?1. break the data into spatial bins on the sky, sizes
chosen for good S/N (not obvious)
2. Calculate the expected atm. background in bins
3. Apply Poisson statistics, discover things or set limits
September 2004 Now 2004; Maury Goodman
Bins
• Being a spherical sky, an igloo pixelization works better than the alternatives
• Problem: a source on a bin boundary would be unnoticed– Doing multiple offset
surveys solves this but kills sensitivity with trials factors
September 2004 Now 2004; Maury Goodman
Cones
• Another approach: overlapping cones– Any point in the sky is
near center of at least one cone
– Fewer bin-edge problems, but must deal with odd oversampling effects
September 2004 Now 2004; Maury Goodman
Unbinned Searches
How about avoiding bin edges entirely?
Try 2-point correlation functionUsed for galactic large-
scale structure searchesProblem – best for large
scale structure, not so sensitive to small clusters
Protheroe statistic …
September 2004 Now 2004; Maury Goodman
• Haven’t seen any sources in an all-sky survey, so limits can be set on any given potential point source
• To test your favorite model of production at some high energy astrophysical source:– Up- near sources counted,
4o ½ angle cone shown here– Expected count from atm.
background calculated– Compute flux limits for
modelers to play with– SGR’s/Magnetars of current
interest
Pick a Source, Any Source
Source BG
Acceptance
x106cm2
90% c.l. limit
x10-14cm-2s-1
Cyg X-1 6 2.54 3.731 1.486
Cyg X-3 3 2.40 3.083 1.049
Her X-1 2 2.53 3.718 0.680
Sco X-1 3 2.95 6.533 0.465
Vela X-1 8 3.69 8.040 0.798
Crab N. 1 2.57 4.776 0.420
3C273 5 2.70 5.814 0.795
Per A 2 2.49 3.010 0.842
Vir A 4 2.76 5.329 0.712
Coma cl. 4 2.67 4.358 0.881
Gal. C. 1 3.51 7.144 0.269
Geminga 3 2.90 5.034 0.607
Mrk 421 2 2.62 3.414 0.734
Mrk 501 3 2.33 3.233 1.008
1ES1426 1 2.33 2.830 0.713
SGR 1900+14 2 2.51 5.483 0.461
SGR 0526-66 6 5.17 12.070 0.341
1E 1048-5937 5 5.98 11.920 0.273
SGR 1806-20 2 2.84 6.734 0.365
GX339-4 4 4.39 9.194 0.345
SMC X-1 5 4.90 12.203 0.293
September 2004 Now 2004; Maury Goodman
Supernova Remnant Neutrinos
September 2004 Now 2004; Maury Goodman
SN Relic
Look for the sum of all SNe long long ago in galaxies far far awaySupernovae Relic Neutrinos (SRN)
Provides a direct test of various early star-formation models by integrating over all stars and the whole universe
Expected signal !
1Lucas, G., 1975
September 2004 Now 2004; Maury Goodman
SN Relic S/N
8B flux
hep flux
atm. e flux
SRN window!
September 2004 Now 2004; Maury Goodman
Super-K SNR limit
• Flux limit < 1.2 cm-2 s-1
above 18 MeV• Super Kamiokande
Collaboration Phys.Rev.Lett. 90 (2003) 061101
atm. e
Michel e
DataTotal bg90%cl SRN
September 2004 Now 2004; Maury Goodman
Recent estimates
September 2004 Now 2004; Maury Goodman
SNR an expected UNO signal
• With 450 kton fiducial volume, expect 20-60 events per year
• This is a background limited search• Deeper underground – better sensitivity
• One sigma “hint” expected in 0.5 to 6 years.
September 2004 Now 2004; Maury Goodman
Other searches in large water detectors
September 2004 Now 2004; Maury Goodman
WIMP Detection
• WIMPs could be seen indirectly via their annihilation products (eventually ) if they are captured and settle into the center of a gravitational well
• WIMPs of larger mass would produce a tighter beam – Differently sized angular windows allow searches to be
optimized for different mass WIMPs SK Paper submitted to PRD
September 2004 Now 2004; Maury Goodman
WIMPs in the Earth
Unosc atm MCDataOsc atm MC
• WIMPs could only get trapped in the Earth by interacting in a spin-independent way– All those even heavy nuclei
in the Earth with no net spin
• from WIMP annihilation would come from the nadir– No excess seen in any sized
angular cone (compared to background of oscillated atmospheric Monte Carlo)
September 2004 Now 2004; Maury Goodman
Earth WIMP-induced Up- Limits
• Resulting upper limits on the WIMP-induced up- from the center of the Earth vs. WIMP mass– Varies as a function of
possible WIMP mass– Lower limits for higher
masses are due to the better S/N in smaller angular search windows
– Lowest masses ruled out anyway by accelerator searches
September 2004 Now 2004; Maury Goodman
Earth WIMP-induced Up- Limits
• Resulting upper limits on the WIMP-induced up- from the center of the Earth vs. WIMP mass– Varies as a function of
possible WIMP mass– Lower limits for higher
masses are due to the better S/N in smaller angular search windows
– Lowest masses ruled out anyway by accelerator searches
UNO
September 2004 Now 2004; Maury Goodman
Sun WIMP-induced Up- Limits
• Resulting upper limits on the WIMP-induced up- from the Sun vs. WIMP mass
• Same features as from Earth– But probes different
WIMP interactions– Unfortunately hard for
South Pole detectors to see the Sun (it’s always near the horizon)
September 2004 Now 2004; Maury Goodman
Other searches
• WIMP’s from the galactic core• Galactic “Atmospheric” ’s• Diffuse AGN Search• Coincidence with Gamma Ray Bursts• Coincidence with xxx
September 2004 Now 2004; Maury Goodman
Status of Megaton Water Cherenkov proposals
September 2004 Now 2004; Maury Goodman
UNO goal
Reminder, the main goal is proton decay
September 2004 Now 2004; Maury Goodman
UNO sensitivity(t)
Super-K
91.6 ktyr
5.7x1033 yr
September 2004 Now 2004; Maury Goodman
UNO Conceptual Design
September 2004 Now 2004; Maury Goodman
FREJUS
2) Components of the Project
-> a very large Laboratory to allow the installation of a Megaton-scale Cerenkov Detector ( 106 m3)
Present Tunnel
FutureSafety Tunnel
Present Laboratory
Future Laboratorywith Water Cerenkov Detectors
CERN
FRÉJUS
and (or) neutrino beta-beam
Three types of geometry that will be consideredin the preliminary study for the future Lab.
September 2004 Now 2004; Maury Goodman
Frejus
13 km (12 870 m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2122 232425262728293031323334
70m x 70m x 250m
France Italy
Future Lab.
Present road Tunnel at Fréjus (grey)andfuture Tunnel (black) for safety (*) and for an independent access to the Fréjus Lab(s)______________________________________________________ (*) with 34 bypasses (shelters) connecting the two Tunnels
September 2004 Now 2004; Maury Goodman
US sites
Henderson
September 2004 Now 2004; Maury Goodman
Henderson Mine Overview
Mine is owned by:Climax Molybdenum Company,a subsidiary of Phelps Dodge Corporation
Mine product: Molybdenum ore (Moly)Mining method: Panel Caving (Block Caving)Production rate: 21,000 tons per dayMine life: About another 20 years
Henderson is the 6th or 7th largest underground hard rock mine in the world.A 28 ft diameter shaft from surface (10,500 ft) to 7500 level capable of hauling up to 200 people at a time. Trip down takes about 5
minutes.
September 2004 Now 2004; Maury GoodmanAp
, 2
004
UN
O C
olla
bora
tion
M
eeti
ng
Henderson Mine Overview
September 2004 Now 2004; Maury GoodmanAp
, 2
004
UN
O C
olla
bora
tion
M
eeti
ng
Underground Lab layout
Two access tunnels. 20 by 18 ft.
2*3600 ft @ 10% grade.
Estimated access costs $11 million
Estimated UNO ex. cost $81 million
Total excavation cost $120 million (30% cont.)
September 2004 Now 2004; Maury Goodman
Tochibora
September 2004 Now 2004; Maury Goodman
Rock Properties at Proposed Sites Rock Properties at Proposed Sites for Hyper-KAMIOKANDE Cavernfor Hyper-KAMIOKANDE Cavern
Spacing
Condition
Orientation
Poisson's Ratio 0.26 0.25
Location
Items MOZUMI Mine TOCHIBORA MINE Overburden (Subsurface Depth)
Rock Types
870 m 700 m
Hornblende Gneiss, Migmatite, partly with Limestone
Hornblende Biotite Gneiss, and Migmatite
Density 0.026 MN/m3 0.026 MN/m3 Compressive Strength 105 MPa - 120 MPa 150 MPa - 250 MPa Tensile Strength 9 MPa 8 - 10 MPa Young's Modulus 48 GPa 45 - 55 GPa
0.6 - 2 m
Very Rough
Very Favorable
Ground Water None None
0.2 - 0.6 m
Slightly Rough
Favorable
Rock Quality Designation (RQD) 78 % 85 % Rock Mass Ratings (RMR) 79 89
Rock Class (Japanese ) B - CH A - B
Discontinuities
Rock Mass Classification Ⅱ Ⅰ Good Rock Mass Very Good Rock Mass
September 2004 Now 2004; Maury Goodman2 detectors×48m × 50m ×250m, Total mass = 1 Mton
Twin Detector Hyper-Kamiokande
September 2004 Now 2004; Maury Goodman
UNO Meeting
• http://nngroup.physics.sunysb.edu/uno/UNO04-Keystone/
• UNO Collaboration Meeting (UNO04) / Unification Day Workshop
• Keystone Resorts & Conference Center, Keystone, Colorado Oct. 14-16, 2004
• This meeting will include one-day workshop dedicated to Proton Decays in Unification Theories on Oct. 15 and a tour of the Henderson mine on Oct. 16.
• Chang Kee Jung: [email protected], 631-632-8108
September 2004 Now 2004; Maury Goodman
Conclusion
• Astrophysical neutrinos will be an interesting topic for study by huge Water Cherenkov detectors, if they are built
• I don’t think astrophysical neutrinos will be a strong part of the motivation for building Thousand-milli-Megaton Water Cherenkov detectors
• Proton decay is a strong motivation– But that would be another talk
September 2004 Now 2004; Maury Goodman
September 2004 Now 2004; Maury Goodman
Megaton detectors & superbeams
Experiments at neutrino superbeams, and new off-axis experiments to measure 13 need to measure neutrino interactions in the 1-5 GeV region.
Proton decay detectors need to well measure event energies around 1 GeV
It makes sense to many to combine these two in a diverse physics program
This hasn’t been the favored scheme (e.g. P929) for two main reasons1. A proton decay detector needs to be underground2. A water detector quickly loses its e/NC rejection power from
1 GeV to 2 GeV This dual program should be kept in mind as
developments proceed.
September 2004 Now 2004; Maury Goodman
Previous estimates
September 2004 Now 2004; Maury Goodman
WIMPs in the Galactic Core
Unosc atm MCDataOsc atm MC
• WIMPs could get caught in the Really Big gravity well at the center of the Milky Way
• Make a cos() Galactic Center plot for all the up- events– No excess seen
compared to background of oscillated atmospheric Monte Carlo