MEMPHYS
MEgaton Mass PHYSics Detector
N. Vassilopoulos / LAL
on behalf of MEMPHYS Collaboration
without LAGUNA aspects (L.Mosca)
without R&D on PMTs (J.E. Campagne)
without Fréjus Site aspects (M. Russo)
NNN07 - 04/10/07
emphasis: software developments and
MEMPHYNO prototype design
1
MEMPHYS: Underground Laboratory and Detector

underground water Cherenkov at Fréjus
(Alps), Modane, France

total fiducial mass: 440 kton or 550 kton: 3
or 4 cylindrical modules 65X65 m
•
•
size limited by light attenuation length
(λ~80m) and pressure on PMTs
readout : ~3 x 81k 12″ PMTs, 30% cover
Laboratoire
Souterrain
de Modane
(# PEs = 40%cover with 20″ PMTs)

possibility of an additional shaft for Liquid
Argon and/or liquid scintillator detector of
100kton
65m
http://2www.apc.univparis7.fr/APC_CS/Experiences/MEMPHYS/
arXiv: hep-ex/0607026
Contacts: J.E. Campagne and M. Mezzetto
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60m
2
MEMPHYS: Fréjus layout
Excavation reaches near current Lab. 2013
excavation will start
in 2008
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MEMPHYS: Fréjus schedule
2007
2012
2017
2020
depends of course on LAGUNA (European decisions)
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and NNN world coordination
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MEMPHYS: Photodetection

12″ PMTs x ~80000 per shaft, 30% coverage  readout plan:
•
•
•
•
•

ASIC: readout integrated electronics circuit as close to detector
operate with a common high voltage and thus need of variable gain to equalize PMT
response
high speed discriminator to auto trigger on single photoelectron
digitization of charge ADC & of time of arrival over 12 bits to provide large dynamic range
and nano-second accuracy
digital data out: power wires
PMm2 R&D project: integrated circuit & complete module studies and construction
sketch of 4x4 12″ PMTs module
voltages applied through the same cable
Electronics as close as possible to PMTs
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MEMPHYS: Physics

Proton decay

SuperNovae neutrinos
•
materiel taken from (see also for further details)
A. Tonazzo’s talk at NOW06:
MEMPHYS non oscillating Physics,
http://www.ba.infn.it/~now/now2006/
core-collapse understanding, explore violent phenomena in the universe  SN
trigger, star formation in the early universe  Diffuse SN

Neutrino Astrophysics

 oscillation measurements with  beams
materiel taken from J. E. Campagne et al.,
Physics potential of the CERN-MEMPHYS
oscillation project, JHEP04(2007)003
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MEMPHYS: Proton Decay
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MEMPHYS: SN rates at Mton detector
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MEMPHYS: “real time” movie of shock waves effects
0.4 Mton, galactic SN (10kpc) for
invert beta decay
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Fogli et al. hep-ph/0412046
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MEMPHYS: SN trigger
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MEMPHYS: Difusse SN v’s
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CERN-MEMPHYS: Oscillation measurements with  beams
 θ13 discovery reach and
sensitivity to CP Violation
CERN
Fréjus
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CERN-MEMPHYS: Oscillation measurements with  beams
main results

discovery reach of sin22θ13 ≈ 5 x 10-3 3σ irrespectively of the actual
value of δCP
βB beam’s ions/year reduced by 2:
performance is strongly depended on ion
production
 max CP violation (for δCP = π/2, 3π/2) can be
discovered at 3σ down to sin22θ13 ≈ 2(9) x 10-4 for βB
(SPL)
 also, ATM + SPL/βB provides sensitivity to mass hierarchy at
2σ sin22θ13 >≈ 0.02-0.03
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MEMPHYS: Mass Hierarchy from atmosperic  s
If D-CHOOZ finds a non zero value for sin22θ13 then a megaton
water cherenkov detector can make a distinction between the two
hierarchies, R. Gandhi et al., hep-phy/07071723
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MEMPHYS: MC Present Status

Event Generator:

NUANCE for  beam,  Atmospheric & Proton Decay

Simulation (based on Geant4):
• Interface with the OpenScientist v16r0 framework (G. Barrand/LALAPC) provided using distribution kits including Geant4 & CLHEP &
AIDA-IO implementation to RIO (also HDF5, XML)
• 3 modes of running in the same framework:

Interactive Viewing, Batch processing, AIDA_ROOT analysis
• event info from MC, primary + non-Optical photons track infos
• hits: each PM maintain a list of arrival time of optical photons detected
(i.e. photo-cathod efficiency)
transparency by J. E. Campagne
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2km WC Geometry
10% de g Č
1% de g Č
0.1% de g Č
p0 2g
transparency by J. E.
Campagne
g
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m(2GeV)
p
16
m→m-→eOnly detected op. photons
1600ns
Interactive
histogram to identify
the e Michel optical
photons…
transparency by J. E.
Campagne
MEMPHYS v7
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 atmospheric (1-10GeV)
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transparency by J. E.
Campagne
MEMPHYS v7
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MEMPHYS: Simulation Studies for a small scale Prototype
MEMPHYNO
Thomas Patzak, Eddy Richard, Alessandra Tonazzo / APC-PARIS
Jean-Eric Campagne, Nikos Vassilopoulos / LAL-ORSAY
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

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purposes :
•
full test of electronics and acquisition chain
•
trigger threshold studies
•
self-trigger mode
volume ~10 t
at least one matrix of 16 PMTs with DAQ system
(developed by PMm2 project, J.E.Campagne et al.)
install at APC, then at Fréjus lab: max available space:
3x3x3 m3
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

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tests with radioactive sources (monoenergetic,
point-like) and cosmic muons (direction selected
with hodoscope) on surface
measure background level @ underground site
MEMPHYS simulation & visualization code
2x2x2m³ water volume
2 different PMTs’ modules simulated at bottom
side :
4x4 12in PMTs = ~35% coverage (for one
side
pictures for detected
optical photons
electron 10 MeV, pz / p = -1, vtx : centre
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muon 1 GeV, pz / p = -1, vtx : top centre
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MEMPHYS: MEMPHYNO e-, μ- studies
OPs’ arrival times
PEs per PMT
# of PMTs per electron
e- 20MeV
μ- 1GeV
muons generated over the
detector’s surface with pz / p = -1
e- E (MeV)
1
2.5
5
10
15
20
25
PEs / MeV / el
0.2
1.1
1.5
1.7
1.8
1.8
1.8
X 6 (sides)
1.2
6.6
9
10.2
10.8
10.8
10.8
MEMPHYS
2
7.7
10
10.9
11.1
11.2
11.1
10k per energy electrons generated
at the detector’s centre with random
direction
Table: MEMPHYNO’s PEs per MeV per electron
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MEMPHYNO
electrons 10 MeV : vertex finding
 primary vertex fit based only on each PMT’s timing info: ti PMT = ti + TOFi => ti = ti PMT – TOFi
, where TOFi = (n / c) x D, D = distance between each PMT and grid’s coordinates
 maximize estimator E a la SK to find the true vertex of electron :
direction
solid up to 450 around –z
dashed up to 250 around –z
estimator for all grid points vs
distance from true vertex
best fit
electrons generated at the detector’s centre
direction
solid
up to 450 around –z
dashed up to 250 around –z
best fit
1.
2.
3.
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for the primary fit :
grid analysis (5cm spacing) in MEMPHYNO
good resolution for downwards electrons in
x-y plane where is the PMTs’ module
(shown)
resolution becomes worse as pz/p
increases due to one PMTs’ module :
best for perpendicular electrons
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MEMPHYNO
μ
muons 1 GeV
light propagation effect of OPs :
 check correlation of PMT time with distance between
muon’s exit point and detection PMT’s coordinates
pz/p = -1
pz/p = -1
entry/exit: centre
entry/exit: middle
pz/p = -1
entry/exit: edges
pz/p < 0


pz/p = -1 : later produced OPs are detected first
pz/p < 0 : relation not clean
diagonal
trajectory
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MEMPHYNO
simulation work


any detector layout parametrization and
analysis
ring reconstruction and PMT analysis
graphics tools
one detector design example & plots
by E. Richard Stagiaire @APC-PARIS

first steps towards event reconstruction & PID
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MEMPHYS: conclusions, since NNN06

the physics case is still strong, some new studies


LAGUNA has been approved and will finance more site studies in Fréjus as well
as further steps with analysis code and physics studies, in collaboration with LENA
and GLACIER
the photodetector R&D is in progress (PMm2)

a new MC based in GEANT4 is in construction, studies in :
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

a prototype MEMPHYNO is in the design phase to be constructed in 2008-2009. It
will provide studies on:
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vertex finding
light propagation
DAQ
self triggering
threshold studies
work on simulation, mechanical design, PMT R&D at APC & LAL
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Thanks
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MEMPHYS: Fréjus feasibility study
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MEMPHYS: Fréjus summary
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MEMPHYS: Proton Decay, p  e+ p0

search for p  e+ p0 (3 showering event),
efficiency ~ 43%
predictions: p~1034-1036 yrs
bdg: atm -  e  N e  N'p 0
  p > 1.6x1033yrs by SK

 p > 1.6x1035yrs at 90% CL for 5Mt.yr

by MEMPHYS


MEMPHYS coverage 30% with 12”PMTs is equivalent
to coverage 40% with 20”PMTs in terms of #PE.
MEMPHYS relies on the study by UNO, adapting the
results
H2O is best for this channel
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MEMPHYS: Proton Decay, p  K v

search for p  K v (K+ below
cherenkov threshold so the channel is
detected via the decay products of K+ )
•
•
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

K m, monoenergetic m + 6.3 MeV
prompt-g from capture
v
K  p+p0 with p0gg
predictions: p~3x1033-3x1034 yrs
p > 2.3x1033yrs by SK
p ~ 2x1034yrs for 5Mt.yr by MEMPHYS
H2O not as good as LAr, Lsint
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MEMPHYS: SN ν in water Čerenkov detectors
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MEMPHYS: SN and θ13 information
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MEMPHYS: SN neutronization burst
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MEMPHYS: SN shockwave information
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CERN-MEMPHYS: Oscillation measurements with  beams
sensitivity to the mass hierarchy
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MEMPHYS: Oscillation measurements with  beams
sensitivity to octant of θ23
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MEMPHYS: MC analyses
by J. E. Campagne
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MEMPHYNO:
muons 1 GeV

# of PMTs per muon, # of PEs per PMT, opticalphotons’ arrival times :
blacksheet reflective
blacksheet reflectivity=0
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10k muons generated over the detector’s surface with pz / p = -1
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MEMPHYNO
further simulation work

any detector layout parametrization and analysis
One detector example
by E.Richard Stagiaire @APC

ring reconstruction and PMT analysis graphics tools
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MEMPHYNO
detector analysis tools for MEMPHYS/MEMPHYNO
V
Plots by E.Richard
Stagiaire @APC
V

first steps towards event reconstruction & PID
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MEMPHYS: MEMPHYNO analyses & tools
Analyses:
 vertex finding for electrons
 light propagation effects for muons
Tools:
 ring reconstruction and PMT analysis
graphics tools
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