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Hall A g2p/ gep beamlines status. Yves Roblin , CASA. Status. Main design done for g2p at 90 and gep at 80 degrees Checking accuracy of design with refined field map of target Initial design was done approximating the solenoid in transverse configuration by a dipole bend (as in SANE).
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Hall A g2p/gepbeamlines status Yves Roblin, CASA
Status • Main design done for g2p at 90 and gep at 80 degrees • Checking accuracy of design with refined field map of target • Initial design was done approximating the solenoid in transverse configuration by a dipole bend (as in SANE).
G4beamline simulation • Took Choi’s target field map and restricted it to 48 cm radius (about the size of can). • Map is placed and rotated 90 degrees relative to the beam • Beam is generated at exit of last dipole (we did not simulate the dipoles) with the proper X,Y,Z and incoming angles.
G4 beamline simulation results Zero angle at ctr of target
G4beamline simulation results(cont) Design elevation
G4beamline simulation(cont) • Angle agrees exactly with prediction and is zero at center of target • The two dipole magnets had to be adjusted to be at the proper elevation on target. About 3 % adjustment to both magnets. New trajectory would not have required to move elevation of 2nd magnet. • Can we trust that field map?
Field map accuracy ? • Field map gotten from Oxford ? Extended by Choi past a certain distance assuming a current loop. • How good is that? Does it overestimate field? • Ideally, would want to do a TOSCA to check that. • Need coil parameters (distance, sizes, wiring, current, etc..)
Effect on layout • These effects should not affect schedule, does not change need for the stand and beam pipes. At most will be a retuning of the magnet strengths. • No deflection in horizontal plane. So we not going to miss the dump…
commissioning • Will develop a commissioning plan to bring beam on target • Resolve remaining issues such as instrumentation placement