\section{Schedule}

The following table presents an optimal schedule for the 
European project taking into account the key date of the completion 
of the new tunnel excavation around 2010. Soon after, CERN will have to decide
its post-LHC strategy, while nuclear physicists will hopefully choose CERN as
the host laboratory for the EURISOL project. 
We would also like to stress that
the schedule of the neutrino beams from CERN is not constraining the 
start of the other non accelerator items of research. 
\begin{figure}[htb]
\vspace{4cm}
\epsfig{figure=./figures/sch_new.eps,width=\textwidth,angle=0}
%\epsfig{figure=./figures/sch.eps,width=0.6\textwidth,angle=-90}
\end{figure}

\newpage
\section{Conclusions}
In conclusion a megaton scale 
Water \v{C}erenkov detector at the Frejus site will address a series of 
fundamental issues :
\begin{itemize}
\item explore the nucleon decay with a sensitivity an order of magnitude 
better than current limits  on different channels
\item in the case of a galactic or near galactic supernova explosion, 
track the explosion in unprecedented detail providing at the same time 
information on the third oscillation angle beyond what is currently 
achievable in terrestrial experiments
\item provide a trigger for supernova explosions 
for other astroparticle detectors for supernova exploding in a range of up to
3 Mpc, knowing that 1 supernova explosion per year is expected 
within a distance of 
10 Mpc
\item provide a 4 sigma detection of diffuse supernova
neutrinos after 2-3 years of operation 
\item  in association with a superbeam and betabeam from CERN 
obtain a sensitivity to the third oscillation angle down to   
$\sin^2(2\theta_{13}) \sim 10^{-4}$ and detect maximal CP violation at 3 sigmas  
for $\sin^2(2\theta_{13})$ larger than $3\cdot 10^{-4}$
\end{itemize}
A series of other physics topics, not mentioned here, will also be adressed\,:
for instance neutrino physics, as well as 
interdisciplinary topics in rock mechanics, geobiology, geochemistry, 
geohydrology, geomechanics and geophysics that could benefit
from a large scale underground excavation.

We believe that our project compares favorably with other similar
projects around the world, and should be seriously considered as a
very attractive major European project after the LHC. The proposed
strategy is thus the following: a megaton-scale detector could be
installed at Fr{\'e}jus and start physics in 2018. It would start
proton decay and supernova searches, which would last several
decades. As soon as the neutrino beam from SPL is available,
neutrino oscillation studies can start, and the advent of a beta beam
would increase significantly the performances of the detector.

The signatories are eager to see the MEMPHYS project
come to life. They are aware that the actual location of a megaton detector
will depend on many issues, in particular the share of future big equipments
(such as linear colliders) worldwide. They are prepared to do the proposed
physics in any country, and have already set up collaborations with their
japanese and american colleagues. An inter-regional yearly (US-Europe-Japan) 
workshop series NNN-XX (Next generation of Nucleon decay and Neutrino Physics 
detectors) organizes and structures this convergence of interests. 
The authors of this document hope however that Europe will not
miss a unique opportunity to keep a leading role in the underground physics,
complementary to the Gran Sasso.

Furthermore, it is obvious that the current proposal is complementary 
to other proposals for large undergrounds detectors using 
liquid scintillator (LENA) or liquid argon technologies (GLACIER) 
in order to pursue the same physics goals. 
The advantage of the water \v{C}erenkov technique lies on the possibility 
to instrument very large masses, while liquid argon detectors 
can have an excellent resolution and liquid scintillators 
very low detection thresholds for neutrino physics. 
On the technology side the water \v{C}erenkov seems a straightforward 
extension of the existing techniques while for instance the liquid argon  
option presents daring technological challenges. The realisation of the 
complementarities in physics potential and the common R\&D issues 
(large underground caverns and containers: excavation issues and safety, 
large area low cost photodetection and electronics, 
purification and background issues, interdisciplinary issues, etc.) 
prompted the proponents of the above solutions to start federating 
their efforts in order to  exploit the possible synergies in view of 
common future proposals to the European Union ~\cite{Laguna}
and elsewhere.    



\section {Acknowledgements}

The authors would like to thank the engineers of the IN2P3-CNRS laboratories, 
especially Ch. de La Taille (LAL) and J. Pouthas (IPNO), 
for their decisive contributions.


