1. Detector Baseline
EuroNu Meeting, RAL
20 January 2010
Paul Soler

2. Neutrino Factory Far Detector Baseline
Two MIND detectors: one of 100 kton at distance km and one of 50 kton at 7500 km
Dimensions:
15x15m2, length m, segmentation 3 cm Fe, 2 cm scintillator
No performance is gained from adding silver detector
iron (3 cm)
+ scintillators (2cm)
n beam
15 m
B=1 T
50-100kT m
EuroNu, RAL,
20 January 2011

3. Neutrino Factory Far Detector Baseline
Performance obtained in latest MIND analysis, efficiencies and migration matrices are now also part of baseline
Numu efficiency
Anti-numu efficiency
EuroNu, RAL,
20 January 2011

4. Baseline mass of intermediate detector
What mass should be adopted for detector at km?
Two possibilities (50 or 100 kton): baseline now set at 100 kton
The 7500 km detector remains at 50 kton since no significant improvement
Winter
IDS-NF-007
Back: ±20%
Near/far:±2.5
Matter: ±2%
Effect of
Having no
systematics
EuroNu, RAL,
20 January 2011

5. Neutrino Factory Far Detector Baseline
New geometry now approaching octagonal design (14 m), as in MINOS, to be able to implement toroidal field (1-2.2 T)
This is not baseline yet since performance not know, but will probably become baseline after performance determined
EuroNu, RAL,
20 January 2011

6. Silver Channel Far Detector
Silver channel detector and standard oscillations:
A nent (silver) detector was useful for removal of degeneracies in conjunction with golden channel at MIND
An Emulsion Cloud Chamber (ECC) type detector, as in Opera, was considered as part of ISS baseline
However, two MIND detectors, one at 4000 km and one at 7500 km, has better dCP vs q13 coverage than MIND+ECC, especially since energy of NF muons is now 25 GeV (ie. less taus)
No performance is gained from adding silver channel detector
EuroNu, RAL,
20 January 2011

7. Tau Far Detector in Baseline
Non standard interaction:
At source:
At detection:
Through propagation:
Winter, IDS-NF-08:
Test of non-unitarity, measure all probabilities:
Better to do in Near Detector
No improvement from silver channel at FD
Kopp, Ota, Winter PRD 78, , 2008
EuroNu, RAL,
20 January 2011

8. Tau Far Detector in Baseline
Sterile neutrino (3+1):
The nm disappearance plus nm → nt appearance adds information about sterile neutrino mixing angle
However, better to have tau detector at magic baseline for this analysis.
Final conclusions:
A tau far detector not essential for standard oscillation physics programme or for NSI in propagation
Better to concentrate on NSI at source and detection at near detector
Donini et al, arXiV:
EuroNu, RAL,
20 January 2011

9. Water Cherenkov Baseline
The MEMPHYS detector at Frejus tunnel is baseline for CERN based SPL Super Beam or Beta Beam (130 km)
Size: three modules of 3x65mx60m (440 kton) or 3x65mx80m (572 kton) being considered
Photocathode coverage: 30%
Considering 81,000 12” PMTs per module (but options are 8” or 10”)
MEMPHYS
440 kt
65m
60m
EuroNu, RAL,
20 January 2011

10. Near Detectors
Baseline is to have one ND per straight per ring (ie 4 detectors)
Need to check if one ND can measure beam divergence ~0.1/g
What is optimum distance: between m
How much shielding do we need?
EuroNu, RAL,
20 January 2011

11. Near Detector Block Diagram
Near Detector design will need three sections:
Vertex detector for charm/tau measurement at the front.
High resolution section (SciFi tracker or TRT tracker) for leptonic flux measurement
Mini-MIND detector for flux and muon measurement
n beam
3 m
B>1 T
~20 m
High Res Detector
Mini-MIND
Vertex
Detector
EuroNu, RAL,
20 January 2011

12. Baseline: Scintillating Fibre Tracker
One station: 4 planes fibres (4mm+ 50 mm scintillator)
20 stations
Dimensions: 1.5x1.5x1.1 m3 (2.5 tonnes)
23,000 fibres/station x 20 stations
Can deliver leptonic physics programme at ND
EuroNu, RAL,
20 January 2011

13. Alternative: High resolution TRT
High resolution magnetised detector (HiResMn)
LBNE near detector proposal
Mishra, Petti,
South Carolina
EuroNu, RAL,
20 January 2011

14. Tau/Charm detector Silicon vertex detector for tau/charm:
Use NOMAD-STAR as a model for this detector
NOMAD-STAR had 5 layers silicon 72cmx31cm with B4C target (45 kg)
In Neutrino Factory would need more layers but similar mass (~100 kg)
References: NIMA 413 (1998), 17; NIMA 419 (1998), 1; NIMA 486 (2002), 639; NIMA 506 (2003), 217; NIMA 569 (2006), 127)
EuroNu, RAL,
20 January 2011

15. NOMAD-STAR and charm Used NOMAD-STAR to search for charm events
Used impact parameter performance (measured at 33mm) of NOMAD-STAR and kinematic constraints of D0, D+, Ds+ decays
Efficiencies from analysis: 3.5% for D0, D+ and 12.7% for Ds+ detection
Fiducial volume small (72cmx36cmx15cm), only 5 layers and only one projectionwould improve with more layers (to be studied)
From 108 CC events/yr (0.1 ton), about 3.1x105 reconstructed charm
M.Ellis PhD thesis;
J.Phys G.29 (2003), 1975;
NIMA 569 (2006), 127)
EuroNu, RAL,
20 January 2011

16. Tau detection through impact parameter
Impact parameter technique through Si vertex detector (NAUSICAA) was studied in NIMA 378 (1996), 196.
Impact parameter resolution nm-CC=28mm
Impact parameter resolution nt-CC=62mm
Efficiencies:
tm: e=10%
tp(np0): e=10%
tppp(np0): e=23%
Total eff: e=0.85x10%+0.15x23%=12%
st/sm=0.49 for <En>~23 GeV
d~90mm nm nt
EuroNu, RAL,
20 January 2011

17. Neutrino Factory Near Detector for taus?
Rates: approx 108 nm CC events/year in 0.1 ton detector
Assume 12% eff from NAUSICAA and st/sm=0.49
Tau looks like charm so charm background a problem
Inclusive charm production at 27 GeV (from CHORUS): 6.4±1.0%
From GeV: ~4%4x106 charm events!!
Charm produced in CC reaction with d or s quark so always have lepton
Associated charm in NC interaction (see charm review De Lellis et al. Phys Rep 399 (2004), )
For anti-ne background could create D- which looks like signal, but need to identify e+ to reject background!!!
So, very important to have light detector (ie Scintillating Fibre tracker) behind vertex detector to identify positron (B-field as well) with high efficiency: assume ~50% (still have 2x106 background for 3.5x106 signal)
Even if we could use kinematic methods a la NOMAD to reduce all background:
(in 0.1 ton)
Very tough analysis!
EuroNu, RAL,
20 January 2011
Current NOMAD best limit:

18. Conclusions
MIND detectors at 4000 km with 100 kton and 7500 km with 50 kton mass is baseline for NF
Silver channel has been removed from NF baseline since it doesn’t improve sensitivity or NP reach
Water Cherenkov detector (MEMPHYS) includes three modules 65m diameter with 60m height (440 kt) but studying increasing to 80m height (572 kt)
Near detectors:
Four detectors at each straight of storage ring
Three components at NF: vertex + SciFi tracker + muon spectrometer
For SB and BB do not need vertex detector
SciFi tracker: 2.5 ton
Tau/charm can be reconstructed in 0.1 ton vertex detector – charm analysis feasible but tau analysis for NSI difficult due to wrong sign charm background at NF
EuroNu, RAL,
20 January 2011