Accurate simulation of the electron cloud in the Fermilab Main Injector with VORPAL

Precision simulations of the electron cloud at the Fermilab Main Injector (MI) have been studied using the plasma simulation code VORPAL. The physical model is fully 3D and self consistent on the time scale of a few hundred nanosec. Solutions that include Yee-type E.M. field maps, electron spatial distributions and the time evolution of the cloud have been generated. By “precision simulations”, we mean that systematic uncertainties in the calculation are studied and quantified. Preliminary results on the comparison between our results and those obtained by the POSINST code are discussed. Based on the results of these simulations and the ongoing experimental program, two distinct new experimental techniques are briefly mentioned. The first one is based on the use BPM plates placed in dipole fields that are made of material(s) for which the secondary emission is well characterized. The second technique would be based on the optical, or ultra-violet, detection of the radiation emitted (inverse photo-electric effect) when the cloud interacts with the inner surface of the beam pipe. As the microwave absorption experiment, this technique is non-invasive and has the advantage of providing spatial images of the cloud as well as accurate timing (ns) information. However, our first priority should be to measure the secondaryemission yieldfor the scrubbedstainless steel beam pipe, in-situ, as this is the most basic unknown quantity in the problem. While mechanically challenging, this in-situ measurementis required,as thesecondaryemission yield depends on the exposure to the beam and other factors.