A new Tevatron Collider working point near the integer

It is well established that in hadron colliders the beam-beam interaction is more harmful in the presence of machine resonances of the form mv/sub x/+nv/sub y/=p, where mod m mod + mod n mod is the order of the resonance. Since the closest a resonance line can be to the integer stopband is 1/order, the closer the working point is to the integer, the fewer lower-order resonances there are to enhance the beam-beam effects. A shift of the working point of the Tevatron from 19.4 to values near 19 and 20 has been studied. Problems with closed-orbit control, dispersion matching, and matched low beta insertions were considered. An excellent solution for the B0 insertion was found which has an improved beta *. A new injection optics allows a transition to the low beta optics which is much easier than the one now used. Results from the first machine studies demonstrate the ability to control the orbit with tunes of 19.03 horizontal and 20.03 vertical. Further studies require the activation of additional quadrupole compensation circuits.<
>