Date post: | 15-Jan-2016 |
Category: |
Documents |
View: | 220 times |
Download: | 0 times |
zoneconvective
2e-+4p 4He+2e MeVcoeur
zoneradiative
500'000 km
(70% 1H, 28% 4He,...)
e
L=1.44 1011 m.
Le soleil
100
10-2
101
10-1
10-3
107
106
105
104
r[R ]
g cm-3]T[K]102108
T=107K: plasma with Tcin0.8 keV,
enough for penetration through Coulomb barrier via tunnel effect,
nuclear reactions
8B 8Be+e++e+14.6 MeV
3He+3He 4He+2p+12.86 MeV
p+p 2H+e++e+0.42 MeV
0.25 %99.75 %
2H+p 3He++5.49 MeV
3He+4He 7Be++1.59 MeV
86 %
14 %
Q=26.2 MeV
p+e-+p 2H+e+1.44 MeV
7Be+e- 7Li+e+0.87 MeV 7Be+p 8B++0.14 MeV
99.89 % 0.11 %
7Li+p 4He+4He+17.35 MeV
Q=25.7 MeV
8Be 4He+4He+3 MeV
Cycle pp(98.5 % de la luminosité)
12C+p 13N+
13N 13C+e++e (1.2 MeV)
13C+p 14N+
14N+p 15O+
15O 15N+ e++e (1.73 MeV)
15N+p 12C+4He
Cycle CNO (1.5 % soleil)
112 MeVscm
SNO
• CC interaction sensitive only to e. Proposed by Pontecorvo in 1946.
N* is extracted from the target with physical-chemical techniques and identified by its decay back in N.
1 Solar Neutrino Unit [SNU] = 1 interaction/sec each 1036 target atoms.
Radiochemical experiments e*NNe
2-46i cm 10 ~
)()(
)(i)( target dEPdE
EdENRRatenInteractio ee
ii
eAuger,raysXN*Ne eL,K
37Cl(e,e)37Ar (Ethr = 813 keV) Kshell EC t = 50.5 d
37Cl + 2.82 keV (Auger e-, X)
615 t C2Cl4 tank, in Homestake mine (4400 mwe) 30102.2 37Cl atoms (nat abundance 24 %)
Every 30 days inject 0.2 cc Ar, purge with He to remove 37Ar, fill prop. counter
pep 0.2 SNU 7Be 1.2 SNU 8B 6.2 SNU CNO 0.4 SNUTot calc. 8.1 ± 1.8
Measured 3.23 SNU ± 0.68 (0.46-0.08=0.38 atom/day)
cosmic background
Bahcall and
Pinsonnault
+SSM
Gallex-GNO Gran Sasso lab (3500 mwe)
)d4.11T(
GaEC
eGeGa
2/1
e71
7171e
30 t of Ga (40 % 71Ga) GeH4
Eth=0.233 MeV
Calibration with 51Cr source
day-1 SNU
pp 0.61 70.8 pep 0.02 3.0 7Be 0.30 34.3 8B 0.10 14.0 CNO 0.08 9.9 tot 1.14 132
tot 0.61 70.8 4
tot 66.9 5
BP+SSM
Gallex-GNO measured
SAGE (metallic Ga)
Deficit of solar neutrinos
Superkamiokande (Japon) :
50 kt H2Ophotomultiplicateurs
queatmosphéri,
)km104.1L(solaires
e
8e
)km300L(KEK
)km1200030L(
ee ee XeNXN e
)()()()(
XeNXN e
1000 tonnes D2O
12 m diameter Acrylic Vessel
18 m diameter support structure; 9500 PMTs (~60% photocathode coverage)
1700 tonnes inner shielding H2O
5300 tonnes outer shielding H2O
Urylon liner radon seal
depth: 2092 m (~6010 m.w.e.) ~70 muons/day
Sudbury Neutrino
Observatory
SNO, construction of acrylic vessel
Acrylic vessel+PMT
Water purification system Photos courtesy of SNO
Neutrino Reactions in SNO
- Q = 1.445 MeV- good measurement of e energy spectrum- some directional info (1 – 1/3 cos)- e only
- Q = 2.22 MeV - measures total 8B flux from the Sun- equal cross section for all active flavors
NCxx
npd
ES e−e− x
- low statistics - mainly sensitive to e, some and - strong directional sensitivity
CC e−ppd e
x
Čerenkov Detection
PMT MeasurementsPMT Measurements
-positionposition-chargecharge-timetime
Reconstructed EventReconstructed Event
--event vertexevent vertex-event direction-event direction-energy-energy-isotropy-isotropy
SNO Neutral Current Trilogy
Pure D2O
Nov 99 – May 01
n d t
(E = 6.25 MeV)
good CC
PRL 87, 071301 (2001)
PRL 89, 011301 (2002)
PRL 89, 011302 (2002)
“D2O Archival Long Paper” in progress
Salt
Jul 01 – Sep 03
n 35Cl 36Cl
(E = 8.6 MeV)
enhanced NC and event isotropy
PRL 92, 181301 (2004)
“Long Salt Paper” soon to be submitted
3He Counters
Fall 04 – Dec 06
n 3He t p
proportional counters = 5330 b
event-by-event separation
“First NCD Paper” in the future
Physics Motivation
Event-by-event separation. Measure NC and CC in separate data streams.
Different systematic uncertainties than neutron capture on NaCl.
3He array removes neutrons from CC, calibrates remainder. CC spectral shape.
Detection Principle
2H + x p + n + x - 2.22 MeV (NC)
3He + n p + 3H + 0.76 MeV
40 Strings on 1-m grid
398 m total active length
x
nNCD
PMT
SNO Phase III: 3He Detectors 3He Proportional Counters (“NC Detectors”)
391 days salt phase
Favored channel: ,e
N=235U, 238U, 239Pu, 241Pu
fission/MeV58.200Q
5.2kQnk)Z,A()Z,A(UUn 2211
236
92
235
92th
600 K (PWR)
A
Fragment distribution
ee)1Z,A()Z,A(
MeV70E
fission/65 e
PWR: 238U+3.5 % 235U (start)
nth+239Pu, 241Pu
nfast+238U
MeV8.1TE
MeVcm1014.9ApEA
e
2244
ee
nepe
e e (disappearance experiment)
Pth= 8.4 GWth, L = 1.050 km, M = 5 t
overburden: 300 mwe
CHOOZ
nepe
• Prompt e+, EP=1-8 MeV, visible energy
• Delayed neutron capture on Gd, ED=8 MeV
• Prompt(/) - Delayed(/) some pulse shape discrimination information
• Directionality: weak & statistical (to be studied for the future)
Time correlation: 30sec
Space correlation: < 1m3
prompt event:
E prompt E En 0.8 MeVQ~1.8 MeV Threshold
0.7-9 MeV
delayed event:MeV)8(~'* sGdGdn
6-11 MeV
CHOOZ
Gd loaded scintillator (0.1 %)
CHOOZ
CHOOZ
2244ee MeVcm1014.9ApEA
KAMLAND
KAMLAND
Chooz: 13<130
solar
Kamland Kamland + solar
solar: Cl37+Gallex+SAGE+SK+SNO
reactor: Kamland
allowed area (95 % CL)
SK: day-night assymetry
measured: %6.18.1A 3.16.1N
,e
SK atmospheric neutrinos
ExpectedBest fit
Favored channel:
Favored channel:
Provide an unambiguous evidence for oscillations in the region of atmospheric neutrinos by looking for appearance in a pure beam
Search for the subleading e oscillations (measurement of 13 )
732 KmGiven the distance (732 Km): flux optimized for the maximal number of charged current interactions
<L/E> = 43 Km/GeV : « off peak »
<E> 17 GeV
(e+e)/ 0.87%
/ 2.1%
prompt negligible
CNGS PROGRAM:
OPERA: 6200 CC+NC /year 19 CC/year (@ 2 10-3 eV2)
8.3kg
10 X0
Pb
Emulsion layers
1 mm
The basic unit: the « Brick »
• Based on the concept of the Emulsion Cloud Chamber (ECC)• 56 Pb sheets 1mm + 56 emulsion layers• Solves the problem of compatibility of large mass for neutrino interactions + high space resolution in a completely modular scheme
ECC are completely stand-alone detectors: Neutrino interaction vertex and kink topology reconstruction Measurement of the momenta of hadrons by multiple scattering dE/dx pion/muon separation at low energy Electron identification and measurement of the energy of the electrons and photons
10.2 x 12.7 x 7.5 cm
ECC Tecnique validated by the direct observation of : DONUT 2000
supermodule
8 m
Target Trackers
Pb/Em. target
ECC emulsions analysis:
Vertex, decay kink e/ ID, multiple scattering, kinematics
Extract selected brick
Pb/Em. brick
8 cm Pb 1 mm
Basic “cell”
Emulsion
trigger and localization of neutrino interactions muon identification and momentum/charge measurement need for a hybrid detector
Electronic detectors:
Brick finding, muon ID, charge and p
Link to mu ID,Candidate event
Use of the electronic detectors:
Spectrometer
Target Tracker
XY planes, 7000m2 in total32256 Scintillator strips 6.86m x 2.6cm x1cmAMCRYS-H (Kharkov) + Kuraray WLS
1000 MaPMT Hamamatsu 64channelsDedicated Front End electronics for gain correction Autotriggerable and threshold @ 1/5 p.eEthernet DAQ cardsWell above 5 p.e. /
readout end
(in the middle: worst case for two-end readout)
6.9m
Construction of the modules in progress (8/week)Installation at LNGS since September 2004
1.7 m
0 max
p.h.
Neutrino interaction trigger
Brick localization Muon tracking and ID
64 strips/module
OPERA structure with two Super-Modules
31 target planes / supermodule (in total: 206336 bricks, 1766 tons)
TargetsMagnetic Spectrometers
Proposal: July 2000, installation at LNGS started in May 2003
SM1 SM2
Data taking starts in 2006, prepare scanning!
sensitivity
full mixing, 5 years run @ 4.5 x1019 pot / year
signal
(m2 = 1.9 x 10-3 eV2)
signal
(m2 = 2.4 x 10-3 eV2)
signal
(m2 = 3.0x 10-3 eV2)
BKGD
OPERA1.8 kton fiducial
6.6(10) 10.5(15.8) 16.4(24.6) 0.7(1.06)
(…) with CNGS beam upgrade (X 1.5)
m2 (10-2 eV2)
Probability of observing in 5 years a number of candidates greater than a 4 background fluctuation
13, or Ue3= Y. Giomataris and J.D. Vergados
Xenon(?) at 1 barR determined from lateral diffusion
3H 3He+e+e- (Q=18.6 keV)6x1018 /s
Tmax=1.27 keVEth=200 eV
Neutrino energy
(T>200 eV)
R(m)m2=2.5x10-3
eV2
=0.17