PSI-21-january-2004MEG Drift chambers1 1)Hardware Foils Hood Inner cathode Prints and preamps 2)Software and analysis Malte‘s Garfield isochronal Lines and drift time calibration Calibration of cathode to anode ratio‘s,.... 3)2004 MEG Drift chambers

PSI-21-january-2004MEG Drift chambers2 New foil sample (.25  m Al), ~ 5 x 5 cm good quality 36 kCHF for 40 foils final design 1.Shape of the frame 2.Deformation by mechanical pre-tension Precise measurements (.1 mm) Flexibility in the procedure to digest differences between old and new foil

PSI-21-january-2004MEG Drift chambers3 Tension of the foil must give the same torque as the forces used to pre-tension the frame Constant during manipulation New tool to ‚transport‘ the frame, groove with O-ring around the edge to pump Inner cathode frame

PSI-21-january-2004MEG Drift chambers4 hood frame

PSI-21-january-2004MEG Drift chambers5 Same informations as for the inner cathode modify design of frame, f. ex. He „bag“ at the same pressure as chambers, bubbler,.... !! tool is very efficient !!

PSI-21-january-2004MEG Drift chambers6 Garfield calculation and calibration of drifttime

PSI-21-january-2004MEG Drift chambers7 a)Practically identical in both directions b)Small effect of magnetic field c)Garfield OK to a few %

PSI-21-january-2004MEG Drift chambers8 Wire 1 Wire 2 Plan 1 Plan 4 x 1.10 x 1.05 x 1.00

PSI-21-january-2004MEG Drift chambers9 Norm_cath 1 = ( x1 + y1*sin(  ))*(1 + p1*sin(  ) ) (1) Norm_cath 2 = ( x2 - y2*sin(  ))*(1 + p2*sin(  )) (2) Norm_cath 3 = (x3 + y3*cos(  ))*(1 + p3*cos(  )) (3) Norm_cath 4 = (x4 - y4*cos(  ) )*(1 + p4*(cos(  )) (4) p1,p2,p3,p4 correction for the trackside For each event and each wire: S1 : sin(  from equation 1 C3 : cos(  from equation 3 S2 : sin(  from equation 2 C4 : cos(  from equation 4 Software and calibration Only ratio‘s are important,right-left,anodes-cathode

PSI-21-january-2004MEG Drift chambers10  1 = atan2(S1,C3)  2 = atan2(S2,C4)  m =.5*(  1+  2) Minimize  event( abs( S1-sin(  m) ) + abs( S2-sin(  m) ) + abs( C3-cos(  m) ) + abs( C4-cos(  m) ) +  cath (abs(Norm_cath j -meas j )) Procedure works with defined p1,p2,p3,p4 more to do on minimalisation function Quality of the procedure seen only after fit of trajectories (particularly effects of p‘s)

PSI-21-january-2004MEG Drift chambers11

PSI-21-january-2004MEG Drift chambers12 Plan wires 11 22 Choose the correct combination of and with the Maximum of cos(  1) + cos(  2)

PSI-21-january-2004MEG Drift chambers Design of Prototyp Optimise construction procedure and get all informations for foils and frames access MC (Hajime) to look for alternativ solutions „final“ design test run in summer

PSI-21-january-2004MEG Drift chambers14 1.Non magnetic preamp and cable 2.Anode print test chamber (1:1) no cathode strip Print, non magnetic preamp and cable,...sampling chip Can be modified to have cathode