1. T2K at Université de Genève
 today
T2K clever ideas
ND280
schedule
outline
N. Abgrall, P. Bene, A. Blondel, A. Bravar, M. Di Marco,
D. Ferrere, F. Masciocchi, M. Ravonel, E. Perrin
19-20 octobre 2006
Workshop on "Neutrinos and flavors physics"
CHIPP (Berne)

2. neutrino today Minos 1st results + Opera start : 2006 still unknown:
Gerda: construction starts …now !
Double-CHOOZ : data from far detector 2008, data with both detectors 2010
T2K: J-parc ready 2008, data 2009
NOvA : approval for construction 2007, data 2010
Katrin : start data taking fall 2009, full sensitivity 2015
still unknown:
oscillation parameters
12 m12 23 m23
13
  CP violation
absolute mass
nature: majorana or dirac ?
good timing !
 disappearance : precision measurement
e appearance : discovery ! improve sensitivity to sin2 213 by an order of magnitude
search for sterile components by NC events
drives the
design

3. T2K clever ideas far detector already exists: Super-Kamiokande
off-axis beam: highest intensity, almost monoenergetic
sub-GeV ’s: two-body kinematics 3 2
-like
e-like 0
E  1GeV,  = 0 – 180

4. T2K-I:    high precision
assuming 13~0 : P( )= 1 - sin2223  sin2(1.27 m223  L/E)
goals:
(sin2223
(m223eV
challenge:
detection of oscillation signal
 from CCQE
over background: CC-10
Baseline (L/E)
T.Nakadaira, Nu2006

5. T2K-II:  e discovery
assuming m212 is small: P( e)= sin2213  sin223  sin2(m223  L/E)
challenge:
detection of
oscillation signal
e from CCQE
over backgrounds:
e from NC-0
beam contamination from K,  ~0.2%
T2K: km, 0.8 GeV
Baseline (L/E)
goal: sin2213 0.006

6. T2K-II:  e discovery
T2K physics
T.Nakadaira, Nu2006

7. JPARC- ~0.6GeV n beam 0.75 MW 50 GeV PS (2009 )
K2K & T2K
Phase II:
4 MW upgrade
Phase II
HK: 1000 kt
JPARC- ~0.6GeV n beam 0.75 MW 50 GeV PS (2009 )
SK: 22.5 kt
Kamioka
J-PARC
K2K ~1.2 GeV n beam
0.01 MW 12 GeV PS
(1999 2005)

8. Off Axis Beam Far Det. q low fraction of high energy 
quasi monochromatic beam
oscillation maximum q
Target
Horns
Decay Pipe
Far Det.

9. requirements for near detectors
crucial:  spectrum at SuperK predicted by  spectrum at ND280m x Far/Near ratio
determination of off-axis angle
accuracy <<1 mrad  on-axis detector
CC  and e fluxes at 5%
 off-axis tracking detectors
flux shape, absolute E scale, E resolution
0 production cross sections
 Pi-Zero, Ecal
pid: +/- and e+/e- identification
detection of recoil p+ and - +
e contamination with <10% uncertainty
neutrino interactions in water target
Fermi motion   momentum resolution – 100MeV/c
Near detectors requirements

10. T2K far and near detectors
beam production
near detectors
Super-K p n
140m 0m
280m
2 km
295 km
on-axis
off-axis
muon monitor
beam direction + intensity of  beam “spill-by-spill”
study of systematics
(see talk by A. Badertscher)
not approved yet
Super-Kamioande (50kt)
“Off-axis”:
Measure neutrino beam spectrum
Estimate backgrounds with a precision of <10%
Essential for the measurement of 13
“On-axis”:
control the beam direction
A. Cervera CHIPP 2005

11. T2K (Re13@CERN) ND280m ND2km  monitor SK Possible Future p n
on-axis
off-axis
neutrino decay
volume
A.Blondel CHIPP oct.2006

12. ND280m hall off-axis (~2o) on-axis 37m  19m accuracy of  beam
direction 0.18 mrad

13. ND 280 UA1 magnet (0.2 T) tracker : optimized for CC studies
ECAL (Pb/scintillator):
photons from 0 and pid e/
UA1 magnet (0.2 T)
inner volume: 3.5x3.6x7.0 m3
+ SMRD (side  range detector):
1.7 cm gaps instrumented with scintillator
muons produced at angles near 90° cannot be measured by the TPCs – provide  energy measurement to < 10%
veto activity from  interactions in magnet or walls, basis for a cosmic trigger for calibrations
ND 280
tracker :
optimized for CC studies
POD ( detector):
optimized for  from NC

14.  detector
high statistics measurements of n interactions with electromagnetic showers
scintillating bar tracking planes
interleaved with passive water layers (blue), fiducial = 1.7 tons
statistical subtraction of events in rear from front used to determine oxygen cross sections
~17103 NC single p0 events expected in water target for 1021 pot (1 year)
50-60% efficiency for p0 reconstruction (p > 200 MeV/c)
p0 fake rate ~ 20%

15. ND280 tracker 2 FGD’s: 3 TPC’s: FGD requirements :
σ(p)/p < 10 % at 1 GeV/c
dE/dx capability: separate e / μ
~ 4x105  interactions in a nominal year (1021 POT)
2 FGD’s:
solid active (+ water) target modules
~ 1.2 ton total mass in each FGD module
3 TPC’s:
gas time projection chamber modules
TPC inner volumes ~ 16 kg gas, resulting in ~ 2x103 
FGD
each FGD: 2x2x0.3 m3 target volume, ~1.2 ton
scintillator bars: 1x1x200 cm3 arranged in alternating x-y planes
fine segmentation needed to track low energy protons, in order to distinguish CCQE and non-elastic
the back FGD contains water layers
3cm passive water layers between each x-y scintillator plane
“SiPM” readout

16. Tracker - TPC
low diffusion gas to achieve resolution sufficient for  / e separation:
10% for p < 1 GeV/c
dE/dx resolution: ~ 7%
double wall with field cage as inner wall
gas amplification : Micromegas
Barcelona-Genève-Saclay
see talk by
N. Abgrall
- 6 read-out planes (0.6x2.5 m2)
- Total drift distance 1.25 m
- B=0.2 T E=200V/cm
- Pad size: 0.6 to 0.8 cm
- ~100k channels
Dp/p2=7% in one chamber

17. nm CC event
ne CC event
Side view
Top view

18. Schedule T2K physics run: 2009
SK reconstruction completed April 2006, fully operational July 2006  back to 40% photo-coverage
Beam line construction started in April 2004
50 GeV MR commissioning: 2008
 beamline commissioning: April 2009
ND280 groups now seeking construction funding
April 2007: ND280 hall construction start
May 2008: Install UA1 magnet
Aug-Dec 2008: complete ND280 building
Jan 2009: installation of ND280 detectors
on axis detector
off axis Tracker
Summer/Fall 2009: install remaining detectors
T2K physics run: 2009

19. Swiss contributions to T2K
talk by
N.Abgrall
UniGe: construction of Micromegas modules (84 modules + spares) at CERN: mechanics + automatic bench testing and pad-by-pad calibration (~ channels)
contribution to refurbisment of UA1 magnet (shared contribution by EU groups)
Swiss groups could lead the effort of NA49/T2K
-- Measurement of particle production by GeV protons from carbon target in the NA49 apparatus
UniBe and ETHZ have applied to T2K
-- proposed contribution to ND280 detectors under discussion
-- long term interest in a possible 2km Larg detector
talk by
S.Bravar
talk by
A.Badertscher

20. conclusions T2K is a key experiment in  physics:
natural scale-up from past and actual to future experiments
potential for discovery
funded and under construction
so far on schedule to start in spring 2009
Starting from HARP and K2K, moving on to T2K and possibly NA49, EU and CH are pursuing an increasingly stronger contribution to the Japanese Long-baseline neutrino programme
Université de Genève is involved in
ND280: TPC readout (construction and testing) and software
possibly leading the NA49 effort
temporary website for T2K and T2K-NA49:

24. Target and horn magnets
1st Horn
2nd Horn
3rd Horn
Graphite Target
beam
I=320kA
Graphite target
Prototype
- thermal shock resistant
to MW
- He-gas cooling system
status
1st Horn excitation May Operation at 320 kA July Production of 1, 2, 3 Horns Installation

25. ND280 group Russia Spain Switzerland United Kingdom United States
Canada
UBC, Regina, Toronto, Victoria, TRIUMF, York
France
CEA/Saclay
Italy
Bari, Napoli, Padova, Rome
Japan
Hiroshima, KEK, Kobe, Kyoto, ICRR, Tokyo
Korea
Chonnam, Dongshin, Kangwon, Kyungpook, Gyeongsang, Sejong, Seoul, SungKyunKwan
Russia
INR Moscow
Spain
Barcelona, Valencia
Switzerland
Geneva
United Kingdom
Imperial, Lancaster, Liverpool, Queen Mary, CCLRC, Sheffield, Warwick
United States
Louisiana State, Stony Brook, Rochester, Washington