1. Status Report Beam Working Group 31 January 2007 Presented by L.Gatignon  Revised beam design  Requests to AB department for 2007

2. Niels updated his latest beam design aiming to suppress the e + component  The new design is now documented in some detail in the usual web page: http://cern.ch/doble This page gives a beam description, as well as the Beatch layout, optics, Turtle and Halo simulation outputs http://cern.ch/doble  The general performance (rates, spot sizes, halo) are very similar to the previous design. But depending on the converter thickness (0.5 to 1 Xo)  The e + are reduced by a factor up to 300, whereas the hadrons are reduced by only  10% due to interactions and multiple Coulomb scattering.  Peak particle densities in the Gigatracker are slightly lower than before  The halo increases by about 20% in the straws and LKr, but not preferentially near the beam axis, where it would be most critical. It is essentially unchanged in the large angle vetoes.  The momentum and angular resolutions of the Gigatracker are slightly better

4. Spot Gigatracker Much fewer e + Better spot at Gigatracker Need 10% more protons Niels

6. Note: Angular resolution 16  rad Momentum resolution 0.22% Niels

7. For the SPSC, resource estimates from AB have to be provided Separately for the R&D program and for the Ke2 physics run. Requests for Ke2:  Establish vacuum in the NA48 tank This includes the repair of the leaking ‘guillotine valve’ Possibly this implies a downstream displacement of the HAC…. Try to include vacuum in beam vacuum control  Check that the control equipment (incl. Beam console) is working Some software remains to be written (P0SURVEY, K12SURV, XCLD)  Provide 10 12 ppp on the T10 target  Setup a muon beam  Setup a 75 GeV/c K + beam  Regular checks on the quality of the beam tuning  Efficient access procedures to the ECN3 cavern Note: rectifier control fixed

8. Requests for R&D tests  Break the vacuum at the end of the Ke2 run  Assist the installation of a prototype straw tracker in the NA48 decay tank at the AKR position  Assist the installation of the 18 m long RICH prototype Has to come in pieces, assembly by experts in situ May have to dismount (part of) neutron shielding wall Be aware of some cables and water hoses on the floor Alignment  Reestablish the vacuum  Tune the beam for RICH tests  Assistance for the removal of the RICH vessel  Steer the 75 GeV/c secondary beam close to the straw prototype Optional items:  Removal of HAC and muon walls postponed