Effects of Superposition of Detector Solenoid and FFS Quadrupole Fields in SLC and Correction Methods

摘要

For the so-called superconducting FFS option with L* = 2.2 m, the MK2 solenoid does not overlap Q1, the FFS quad nearest the IP. For the permanent magnet option with L* = 0.75 m, the MK2 solenoid would overlap both Q1 and Q2. In either case an 8 m long solenoid, contemplated for the SLD detector, would overlap both Q1 and Q2. The solenoid field cannot be shielded so in an overlap region one will have a superposition of solenoid an quadrupole fields. Recently, the question was raised, What are the optical consequences when the solenoid and quad fields are superimposed. The question had not been considered before, but rough estimates suggested immediately that there might indeed be ugly consequences in terms of an enlargement of spot size at the IP. The purpose of this note is to answer the question quantitatively and to consider methods of correction of the ugly consequences. (ERA citation 09:029080)