SNO+ (1000 tonnes highly purified Liquid Scintillator): 2010

Erich W. Vogt
Canadian Statesman
in Sub-atomic Physics

TRIUMF and UBC in the SNO Project
Faculty, and TRIUMF Scientists: Chris Waltham, Rich
Helmer, Scott Oser
Post Docs: Salvador Gil, Rob Komar , Thomas Kutter,
Juergen Wendland, Blair Jamieson, Ron Schubank,
Reena Meijer Drees
Graduate Students: Alan Poon, Jaret Heise, Christian
Nally, Tyron Tsui, Louis McGarry, Guy Ouellette
Undergraduates: Mitch Crowe, Bryce Croll, Ben Short,
Ivan Sham, Jamil Sharif, Tudor Costin, Dave Branch,
Jonathan Harris, Rob Newman, Vicky Valiani, Kiara
Moran, Siong Ng, Chris Nell, Chris Callendar, Sam
Marchand, Janice Boyce

Flavour Change for Solar Neutrinos
Solar Model Flux Calculations
CNO
Bahcall et al.
, SNO
Previous Experiments Sensitive
to Electron Neutrinos
SNO was designed to observe separately ν e and all
neutrino types to determine if low ν e fluxes
come from flavor change or solar models

Unique Signatures in SNO (D 2 O)
Charged-Current (CC)
ν e+d → e - +p+p
Ethresh = 1.4 MeV
νe only
Neutral-Current (NC)
ν x+d →ν x+n+p
E thresh = 2.2 MeV
Equally sensitive to νe e νμ ντ Elastic Scattering (ES) (D 2O & H 2O)
ν x+e - →ν x+e -
ν x, but enhanced for ν e
3 ways to
detect neutrons

SNO: 3 neutron (NC) detection
methods (systematically different)
Phase I (D 2O)
Nov. 99 - May 01
n captures on
2 H(n, γ) 3 H
Effc. ~14.4%
NC and CC separation
by energy, radial, and
directional
distributions
2 H+n
3 H
6.25 MeV
Phase II (salt)
July 01 - Sep. 03
2 t NaCl. n captures
on
35 Cl(n, γ) 36 Cl
Effc. ~40%
NC and CC separation
by event isotropy
35 Cl+n
36 Cl
8.6 MeV
Phase III ( 3 He)
Nov. 04-Dec. 06
40 proportional
counters
3He(n, p) 3H Effc. ~ 30% capture
Measure NC rate with
entirely different
detection system.
5 cm
3 H
3 He
p
n
n + 3 He → p + 3 H

The Sudbury Neutrino Observatory: SNO
Acrylic vessel (AV)
12 m diameter
1000 tonnes D 2 O
($300 million)
1700 tonnes H 2 O
inner shielding
5300 tonnes H 2 O
outer shielding
~9500 PMT’s
6800 feet (~2km) underground
Creighton mine
Sudbury, CA
- Entire detector
Built as a Class 2000
Clean room
- Low Radioactivity
Detector materials
The heavy water has recently been returned and development work is in progress
on SNO+ with liquid scintillator and 150 Nd additive.

SNO: One million pieces transported down in the
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.
Over 70,000
Showers
to date and
counting

Christian Nally Jaret Heise
UBC Graduate Students during Detector Construction

Two Undergrads taught by Erich Vogt in their first year at UBC:
Fraser Duncan:
- Detector Operations Manager for SNO
- Deputy Director of SNO
- Associate Director of SNOLAB
Please pass on my best wishes to Erich. He was a strong
supporter of graduate students especially myself (well, in my mind)
during his tenure as Director of TRIUMF. It has special meaning for
me that the seminar to honour him is in Hebb Theater at UBC. The
first lecture of my first day at university 28 years ago (sigh) was
in Hebb Theater and the professor was Erich Vogt. I recall apples
levitating into the rafters... - Fraser
Aksel Hallin:
- Tier 1 Canada Research Chair at Alberta
- Calibration Group Leader on SNO
I came to UBC in 1973 and took the first year honours physics course from
Erich. I remember him as someone who was very approachable and really
enjoyed students. I also remember talking with Erich before deciding to go
to Princeton (his alma mater) for graduate work…. - Aksel

- Major work by Chris Waltham and
his students on the development and
testing of the light collectors
installed on each photomultiplier.
- Alan Poon with testing apparatus in
1990 at UBC. Did his Ph. D. work on
the (p,t) calibration source and is
now the Analysis Coordinator for
SNO as a Staff Member at LBL.

Glove Box and manipulator
system for calibration sources
Roland Roper, Ivor Yhap, Roland Kokke…
Rich Helmer and TRIUMF staff and
students did primary electronics testing
and commissioning as well as providing
major components for the SNO detector.
Rich was the Commissioning Manager.
“Whiffletrees” for load balancing on
ropes supporting the acrylic vessel

6.13 MeV
SNO Energy Calibrations: 25% of running time
19.8 MeV
β’s from 8 Li (Rich Helmer)
γ’s from 16 N
and t(p,γ) 4 He (Alan Poon)
Energy calibrated to ~1.5 %
Throughout detector volume
252 Cf neutrons
Optical calibration at 5 wavelengths with the “Laserball”
+ AmBe, 24 Na

ν μ ,
ν τ
φ
φ
CC
NC
φ
(In
ES
=
=
Electron neutrinos
1.
68
4.
94
= 2.
35
units of
φ
φ
CC
NC
+ 0.
06
−0.
06
+ 0.
21
−0.
21
( stat. )
( stat. )
( stat. )
−2
cm s
+ 0.
08
−0.
09
+ 0.
38
−0.
34
+ 0.
22 + 0.
15
−0.
22 −0.
15
6 −1
10
=
0.
34
±
( syst. )
( syst. )
( syst. )
)
0.
023(
stat. )
+ 0.
029
−0.
031
Flavor change
determined by > 7 σ.
CC, NC FLUXES
MEASURED
INDEPENDENTLY
The Total Flux of Active
Neutrinos is measured
independently (NC) and agrees
well with solar model
Calculations:
5.82 +- 1.3 (Bahcall et al),
5.31 +- 0.6 (Turck-Chieze et al)
Electron neutrinos are
Only about 1/3 of total!

U
li
Using the oscillation framework:
⎛U
⎜
= ⎜U
⎜
⎝U
⎛ c
⎜
= ⎜−
s
⎜
⎝ 0
12
12
where c
ij
e1
μ1
τ1
s
c
If neutrinos have mass:
12
12
0
U
U
U
e2
μ2
τ 2
ij
U
U
U
e3
μ3
τ3
0⎞
⎛1
⎟ ⎜
0⎟
⋅⎜
0
1⎟
⎜
⎠ ⎝0
= cosθ
, and
⎞
⎟
⎟
⎟
⎠
− s
s
c
ij
0
23
23
s
c
0
23
23
= sinθ
ij
⎞ ⎛1
⎟ ⎜
⎟⋅
⎜0
⎟ ⎜
⎠ ⎝0
0
1
0
ν ∑
0 ⎞ ⎛ c
⎟ ⎜
0 ⎟⋅
⎜ 0
e
−iδ
⎟ ⎜
⎠ ⎝−
s
l = U li ν i
For 3 Active neutrinos. (MiniBoone has recently ruled out LSND result)
Solar,Reactor Atmospheric
P(νμ → νe
)
13
13
0
1
0
( 1.
27
s
c
13
0
13
⎞ ⎛1
⎟ ⎜
⎟⋅
⎜0
⎟ ⎜
⎠ ⎝0
Δm
E
e
0
−iα
/ 2
0
2
)
e
0
0
−iα
/ 2+
iδ
For two neutrino oscillation in a vacuum: (a valid approximation in many cases)
2
2 2 L
=
Maki-Nakagawa-Sakata-Pontecorvo matrix
sin
?
CP Violating Phase Reactor, Accel. Majorana Phases
2θ
sin
?
(Double β decay only)
?
Range defined for Δm 12 , Δm 23
3
⎞
⎟
⎟
⎟
⎠

Matter Effects – the MSW effect
i
d
dt
⎡ν
e ⎤
⎢ ⎥
⎣ν
x ⎦
=
H
⎡ν
e ⎤
⎢ ⎥
⎣ν
x ⎦
2
2
⎡ Δm
Δm ⎤
⎢−
cos2θ + 2G
FN
e sin2θ⎥
H = ⎢
4E
4E
2
2 ⎥
⎢ Δm
Δm
sin2θ
cos2θ⎥
⎢⎣
4E
4E ⎥⎦
The extra term arises because solar ν e have an extra interaction
via W exchange with electrons in the Sun or Earth.
In the oscillation formula:
sin
2
2θ
m
=
ω =
−
2
sin 2θ
2
( ω − cos2θ
) + sin
2GF
Ne
E / Δm
(Mikheyev, Smirnov, Wolfenstein)
2
2
2θ
MSW effect can produce an energy spectrum distortion
and flavor regeneration in Earth giving a Day-night effect.
If observed, matter interactions define the mass heirarchy.

SOLAR ONLY
AFTER
SNO SALT
DATA
MSW: Large
Mixing Angle
(LMA) Region
- The solar
results define the
mass hierarchy
(m 2 > m 1) through the
Matter interaction (MSW)
- SNO: CC/NC flux
defines tan 2 θ 12 < 1
(ie Non - Maximal mixing)
by more than 5
standard deviations
LMA for solar ν predicts very small
spectral distortion, small (~ 3 %) day-night
asymmetry, as observed by SK, SNO
Asym O
salt + D = 0 . 037 ±
2
(Scott Oser and students)
SOLAR PLUS
KAMLAND (Reactor ν’s)
0 . 040

Periodicity in Solar Flux?
(Scott Oser and students)
hep-ex/0507079
SNO data 1999-2003
Unbinned Maximum Likelihood
Method compares fit for
Sinusoidal variation with
Expectation for zero amplitude.
Monte Carlo used to estimate
sensitivity shows
35% probability of a larger
likelihood ratio (S) with zero
sinusoidal amplitude than the
maximum S observed in the fits.
Conclusion: No observed
sinusoidal variation at periods
from 1 day to 10 years.
Analysis sensitive to amplitude
of 8-10% at 99% C.L..

SNO Muon & Atmospheric Neutrino Analysis
Analysis:
Chris Waltham,
Thomas Kutter,
Tyron Tsui,
Christian Nally ….
Also: Supernova Watch (SNEWS) (Jaret Heise UBC Thesis)
SNEWS: International collaboration of detectors to watch for burst of
neutrinos from a galactic supernova and alert the astronomical community.

Final Phase: SNO Phase III
Neutral-Current Detectors (NCD):
An array of 3 He proportional counters
40 strings on 1-m grid
~440 m total active length
• Search for spectral distortion
• Improve solar neutrino flux by breaking the
CC and NC correlation (ρ = -0.53 in Phase II):
CC: Cherenkov Signal ⇒ PMT Array
NC: n+ 3 He ⇒ NCD Array
•Improvement in θ 12, as
Correlations D 2 O unconstrained D 2 O constrained Salt unconstrained NCD
NC,CC -0.950 -0.520 -0.521 ~0
CC,ES -0.208 -0.162 -0.156 ~-0.2
ES,NC -0.297 -0.105 -0.064 ~0
Blind
Analysis
Phase III production data taking Dec 2004 to Dec 2006. D 2 O now removed.

Blind Data
Another analysis
is almost complete
that combines data
from
the first two SNO
Phases and
reduces the
threshold by ~ 1
MeV.
This also provides
improved accuracy
on CC/NC flux
ratio and therefore
θ 12 mixing matrix
element.
NCD Phase Signal
Extraction: Jamieson, Oser…
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.

New International Underground Facility: SNOLAB
Phase 1 Experimental area: Available 2008
Cryopit addition: Excavation nearly completed. Available 2009.
Total additional excavated volume in new lab: 2 times SNO volume.
For Experiments that benefit from a very deep and clean lab:
• ν - less Double Beta Decay
• Dark Matter
• Solar Neutrinos
• Geo – neutrinos
• Supernova ν `s
David Sinclair: Director
of Facility Development
TRIUMF Research
Scientist at Carleton
SUSEL

SNOLAB (Same depth as SNO: 2 km)
Cube Hall (2008)
70 to 800 times lower
μ fluxes than
Gran Sasso, Kamioka.
SNO Cavern
(Existing)
Personnel
facilities
Ladder Labs
(2008)
Phase II
Cryopit (2009)
All Lab Air: Class < 2000
Utility
Area

Excavation Status
ryopit Rock Removal
omplete
olting, Shotcrete and
oncrete will be completed
several weeks.
Cryopit
Cube Hall and Ladder Lab
Excavation complete, walls
painted, services being
installed.
Ladder Lab
Cube Hall

Cube Hall

Dark Matter:
Letters of Intent/Interest for SNOLAB
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:
150 Nd: Organo-metallic in liquid scintillator in SNO+
136 Xe: EXO (Gas or Liquid) (Longer Term)
CdTe: COBRA (Longer Term)
Solar Neutrinos:
Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos)
Liquid Ne: CLEAN (also Dark Matter) (Longer Term)
SuperNovae:
SNO+: Liquid scintillator; HALO: Pb plus SNO 3 He detectors.
6 th Workshop and
Experiment Review Committee
Aug 22, 23, 2007
www.snolab.ca
RED IMPLIES APPROVED
FOR SITING

Composition of the Universe as we understand it in 2008
(Very different than 20 years ago thanks to very sensitive astronomical,
astronomical,
astrophysical and particle physics experiments.)
Responsible for accelerating the Universe’s expansion
Neutrinos
Are only
a few %
With SNOLAB we can look for Dark Matter particles (WIMPS)
left from the Big Bang, with ultra-low ultra low radioactive background.

DEAP/CLEAN: 1 Tonne
Fiducial Liquid Argon Dark
Matter (WIMP) detector
- Scintillation time spectrum for Ar
enables nuclear recoils from WIMP
collisions to be separated from
betas and gammas from 39 Ar
background using only scintillation
light.
- DEAP and CLEAN collaborations
have come together to build new
detectors with a simple and easily
scaled technology at SNOLAB.
Queen’s, Alberta, Carleton, Laurentian,
SNOLAB, TRIUMF (Retiere), LANL,
Yale, Boston, South Dakota, New
Mexico, TUNL, Texas, NIST Boulder
Events/0.01 wide bin
Relative probability
8
10
7
10
6
10
5
10
4
10
3
10
2
10
10
10
10
1
-1
-2
10
-3
10
-4
10
-1
10 1 10
10 8 simulated e-’s
From simulation,
γ rejection > 10 8
@ 10 keV
10 keV events
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
2
10
electrons
nuclear recoils
3
10
- e
photon
nuclear recoils
100 simulated
WIMPs
M.G. Boulay & A. Hime, astro-ph/0411358
T
4
10
(ns)
F
prompt

Cube Hall
MiniCLEAN
360 kg
2009
DEAP/CLEAN
3.6 tonne
2010
Assembly
Clean Room
DEAP/CLEAN
Process Systems
DEAP-1 (7 kg): 6 x 10 -8 discrimination of 39 Ar betas demonstrated in running on surface.
Now counting underground. Aiming at better than 10 -9 with lower background there.
Existing discrimination would be adequate if depleted argon (x20) from helium sources is used.

WIMP Sensitivity with 1 tonne of argon
)
2
alized per nucleon (cm
10
-41
10
10
CDMS-2008
-40
-42
CDMS-II
Present
Experimental
Limits
For nominal threshold of 20 keV visible energy, 1000 kg LAr for 3 years is
sensitive to 10 -43
10
Teff
threshold
15 keV
-46 cm2 . Present schedule: Mini-CLEAN 100 kg Fiducial: 2009,
DEAP/CLEAN: 1000 kg Fiducial: starting 2010

NEUTRINOLESS DOUBLE BETA DECAY: SNO+ ( 150 Nd), EXO ( 136 Nd)
Measuring Effective ν Mass: m νββ = |∑ i U ei ²m i |
m νββ = |m 1 cos 2 θ 13 cos²θ 12 + m 2 e 2iα cos 2 θ 13 sin²θ 12 + m 3 e 2iβ sin²θ 13 |
Mass Hierarchies
normal hierarchy inverted hierarchy
Normal Inverted
Next Generation Detectors:
Want sensitivity

Main Engineering Changes for SNO+ : Scint. Purification, AV Hold Down
The organic
liquid is lighter
than water so
the Acrylic Vessel
must be held down.
Existing
AV Support
Ropes
Otherwise, the existing detector, electronics etc. are unchanged.
AV Hold Down
Ropes
(V. Strickland,
TRIUMF Carleton:
Finite element
calcs.)

SNO+: Neutrino-less Double Beta Decay: 150 Nd
• Nd is one of the most favorable double beta decay candidates
with large phase space due to high endpoint: 3.37 MeV.
• Ideal scintillator (Linear Alkyl Benzene) has been identified.
More light output than Kamland, Borexino, no effect on acrylic.
• Nd metallic-organic compound has been demonstrated to have
long attenuation lengths, stable for more than a year.
• 1 tonne of Nd will cause very little degradation of light output.
• Isotopic abundance 5.6% (in SNO+ 1 tonne Nd = 56 kg 150 Nd)
• Collaboration to enrich 150 Nd using French laser isotope facility.
Possibility of hundreds of kg of isotope production.
• SNO+ Capital proposal to be submitted Oct. 2008.
• Plan to start with natural Nd in 2010.
• Other physics: CNO solar neutrinos, pep solar neutrinos to
study neutrino properties, geo-neutrinos, supernova search..
Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP
Lisbon, Oxford, Sussex, Dresden

SNO+ ( 150 Nd ν - less Double Beta Decay)
0ν: 1057 events per
year with 500 kg
150 Nd-loaded liquid
scintillator in SNO+.
Simulation
assuming light
output and
background
similar to Kamland.
U Chain
One year of data
m ν = 0.15 eV
Th Chain
Sensitivity (3 yrs): Natural Nd (56 kg isotope): m νββ ~ 0.1 eV
500 kg enriched 150 Nd: m νββ ~ 0.03 eV

A lead detector for
supernova neutrinos
in SNOLAB
H elium
A nd
L ead
O bservatory
Pb: Most sensitivity to electron neutrinos.
~ 50 events for SN at center of Galaxy.
Laurentian, TRIUMF (Yen),
SNOLAB, LANL, Washington,
Duke, Minnesota, Digipen IT HALO-1: 80 tons of existing Pb
& SNO Neutron Detector Array

R&D in Canada: EXO-gas double beta counter
Micro-megas
Electrode
Grids
Xe Gas
Isobutane
TEA
136 Xe decay
. . . . . . . .
. . . . . . . .
For 200 kg, 10 bar, box is 1.5 m on a side
EXO-gas Canada: Carleton (Sinclair), Laurentian
Anode Pads
WLS Bar
Lasers
Ba Ion
PMT
Electrons

Fluorine is very sensitive for the spin-dependent interaction
Montreal, Queen’s
Indiana, Pisa, BTI
WIMP-Nucleus Spin-Dependent Interaction
Acoustic
Signal
Up to 2.6 kg being run in 2007-08

Summary
Excellent Partnerships in the past and for the future….
All of us in Canadian Subatomic physics owe a
tremendous amount to:

Erich W. Vogt
TRIUMF Director 1981-94
Canadian Statesman
in Sub-atomic Physics