I.Laktineh GranSasso MAY 2003

Stopping / at PSI dE/dX Measurement

Bern, Naples,Neuchatel,Lyon

Aim: to identify stopping pions and muons in the bricks using the dE/dX information.what is the difference with the Japanese attempt? In Europe we can obtain almost a pure beam of pions (muons) at PSI. no need for a sophisticated setup

This will allow more efficient characterization specially with he European scanning system (access to grain information)

At PSI we can use two beam linesPions beam PiM1 with strict cuts on the momentum

P = 200 MeV

Muon beam MuE1

P = 120 MeV muons produced from pion decay

collected in a solenoid.

(more information available on the PSI website)

Purity of each beam is about 99 %

Thanks to Urs, things can be done easily but we have to decideNOW

x(µ)

y(µ)

x(µ)

z(µ)

Muons(without decay products)

Pions(without decay products)

z(µ)

x(µ)

x(µ)

y(µ)

The mean distance of the pions in the brick is 5 cmThe mean distance of the muons in the brick is 2.5 cm Rate: from 100-1000 particles/ cm2

Strategy to follow

Take two bricks (or two half-bricks with lead in front)add 2-3 emulsion sheets together in the front (inside ?)( to cut bgk)

Expose each to both beamsone half for the pions, one half for the muons ( to reduce systematic)

Brick preparation and development at cern (Gianni)Scanning in Lyon, Bern and also in Naples laterInvolved persons: Urs, Jerome, Igor, Samuel, Frederic, Markus, Imad, Perrine, Giovanni, NicolaDevelopment (thickness? More than 44 microns if possible)

When ? July seems to be the best for allScanning:Lyon : (at least 50% of time)Bern : (at least 80% of time)Naples : ?

Conclusions

• Tough but challenging and necessary study for OPERA

• We are collaborating with our Japanese colleagues in order to get profit of their experience (Toshito)

• The European scanning system advantages can be tested

• This study is necessary for the exotic decay of the Lead proposed by the Bologna group (see Miriam talk)

WE REQUEST TWO BRICKS FOR JOLY (if possible)