SNO and the New SNOLAB. Art McDonald Queen’s University, Kingston, Ontario, Canada. , SNO. Bahcall et al. Flavour Change for Solar Neutrinos. Previous Experiments Sensitive to Electron Neutrinos. Solar Model Flux Calculations. CNO.
Queen’s University, Kingston, Ontario, Canada
Bahcall et al.
Flavour Change for Solar Neutrinos
Previous Experiments Sensitive
to Electron Neutrinos
Solar Model Flux Calculations
SNO was designed to observe separately ne and all neutrino types to determine if low ne fluxes
come from flavor change or solar models
Ethresh = 1.4 MeV
Ethresh = 2.2 MeV
Equally sensitive to e nmt
3 ways to
Elastic Scattering (ES)(D2O & H2O)
x, but enhanced fore
SNO: 3 neutron (NC) detectionmethods (systematically different)
Phase I (D2O)
Nov. 99 - May 01
Phase II (salt)
July 01 - Sep. 03
Phase III (3He)
Nov. 04-Dec. 06
n captures on
NC and CC separation by energy, radial, and directional distributions
2 t NaCl. n captures on
NC and CC separation by event isotropy
40 proportional counters
Effc. ~ 30% capture
Measure NC rate with entirely different detection system.
n + 3He p + 3H
6800 feet (~2km) underground
Acrylic vessel (AV)
12 m diameter
1000 tonnes D2O
1700 tonnes H2O
5300 tonnes H2O
- Entire detector
Built as a Class 2000
- Low Radioactivity
The heavy water has recently been returned and development work is in progress
on SNO+ with liquid scintillator and 150Nd additive.
9 ft x 12 ft x 9 ft mine cage and re-assembled under
ultra-clean conditions. Every worker takes a shower
and wears clean, lint-free clothing.
to date and
Energy calibrated to ~1.5 %
Throughout detector volume
+ AmBe, 24Na
b’s from 8Li, g’s from 16N
Optical calibration at 5 wavelengths with the “Laserball”
determined by > 7 s.
CC, NC FLUXES
The Total Flux of Active
Neutrinos is measured
independently (NC) and agrees
well with solar model
5.82 +- 1.3 (Bahcall et al),
5.31 +- 0.6 (Turck-Chieze et al)
Electron neutrinos are
Only about 1/3 of total!
results define the
(m2 > m1) through the
Matter interaction (MSW)
- SNO: CC/NC flux
defines tan2q12< 1
(ie Non - Maximal mixing)
by more than 5
LMA for solar n predicts very small
spectral distortion, small (~ 3 %) day-night
asymmetry, as observed by SK, SNO
KAMLAND (Reactor n’s)
Phys.Rev.Lett. 92 (2004) [Improves limit by 1000]
Neutral-Current Detectors (NCD):
An array of 3He proportional counters
40 strings on 1-m grid
~440 m total active length
Phase III production data taking Dec 2004 to Dec 2006. D2O now removed.
the first two SNO Phases and reduces the threshold by > 1 MeV.
This also provides improved accuracy on CC/NC flux ratio and therefore
q12 mixing matrix element.
Very low Background. About one count per 2 hours in region of interest.
Can be reduced by a factor of more than 20 by pulse shape discrimination.
Phase 1 Experimental area: Available 2008
Cryopit addition: Excavation nearly completed. Available early 2009.
Total additional excavated volume in new lab: 2 times SNO volume.
Cube Hall (2008)
70 to 800 times lower
m fluxes than
Gran Sasso, Kamioka.
All Lab Air: Class < 2000
Cryopit Rock Removal
Bolting, Shotcrete and
Concrete will be completed
in several weeks.
Cube Hall and Ladder Lab
Excavation complete, walls painted, services being installed.
Timing of Liquid Argon/Neon Scintillation: DEAP-1 (7 kg),MINI-CLEAN (360 kg),
DEAP/CLEAN (3.6 Tonne)
Freon Super-saturated Gel: PICASSO
Silicon Bolometers: SUPER-CDMS(25 kg)
Neutrino-less Double Beta Decay:
150Nd: Organo-metallic in liquid scintillator in SNO+
136Xe: EXO (Gas or Liquid) (Longer Term)
CdTe: COBRA(Longer Term)
Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos)
Liquid Ne: CLEAN (also Dark Matter) (Longer Term)
SNO+: Liquid scintillator; HALO: Pb plus SNO 3He detectors.
6 th Workshop and
Experiment Review Committee
Aug 22, 23, 2007
RED IMPLIES APPROVED
Letters of Intent/Interest for SNOLAB
108 simulated e-’s
g rejection > 108
@ 10 keV
DEAP/CLEAN: 1 Tonne Fiducial Liquid Argon Dark Matter (WIMP) detector
Queen’s, Alberta, Carleton, Laurentian, SNOLAB, TRIUMF, LANL, Yale, Boston, South Dakota, New Mexico, North Carolina, Texas, NIST Boulder, MIT
M.G. Boulay & A. Hime, astro-ph/0411358
Ran DEAP-1 on surface to background limit ( 6 x 10-8 PSD) , moved to SNOLAB.
Now running underground for Pulse Shape Discrimination studies and DM search
PSD agrees with
Light alone is
sufficient for 109
for 1 tonne DM
PSD already OK for 1 tonne fiducial Ar if depleted x 20 in 39Ar. (See Galbiati et al)
~ 5 x 10-44
Schedule: Mini-CLEAN (360 kg): 100 kg Fiducial: 2009,
DEAP/CLEAN (3600 kg): 1000 kg Fiducial: starting 2010
Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP Lisbon, Idaho State, Idaho Nat Lab, Oxford, Sussex, TU Dresden
liquid is lighter
than water so
the Acrylic Vessel
must be held down.
AV Hold Down
Otherwise, the existing detector, electronics etc. are unchanged.
SNO+ ( Hold Down150Nd n - less Double Beta Decay)
0n: 1057 events per
year with 500 kg
scintillator in SNO+.
similar to Kamland.
One year of data
mn = 0.15 eV
Sensitivity Limits (3 yrs): Natural Nd (56 kg isotope): mnbb ~ 0.1 eV
500 kg enriched 150Nd: mnbb ~ 0.04 eV
H Hold Down elium
Pb: Most sensitivity to electron neutrinos.
~ 50 events for SN at center of Galaxy.
A lead detector for
SNOLAB, LANL, Washington,
Duke, Minnesota, Digipen IT
HALO-1: 80 tons of existing Pb
& SNO Neutron Detector Array
Electrons Hold Down
R&D in Canada: EXO-gas double beta counter
. . . . . . . .
. . . . . . . .
For 200 kg, 10 bar, box is 1.5 m on a side
EXO-gas Canada: Carleton, Laurentian
WIMP-Nucleus Spin-Dependent Interaction Hold Down
Fluorine is very sensitive for the spin-dependent interaction
Indiana, Pisa, BTI
Up to 2.6 kg being run in 2007-08
SUMMARY Hold Down