Design of a Marx-Topology Modulator for FNAL Linac

TL;DR

This paper presents the design and development of a Marx-topology modulator aimed at improving the reliability and waveform control of the Fermilab Linac's RF system as part of the Proton Improvement Plan.

Contribution

It introduces a novel Marx-topology modulator specifically designed for the Fermilab Linac, including prototype development data and its potential benefits.

Findings

Prototype demonstrates stable waveform shaping

Improves reliability over existing hard-tube modulator

Potential to enhance beam stability and system uptime

Abstract

The Fermilab Proton Improvement Plan (PIP) was formed in late 2011 to address important and necessary upgrades to the Proton Source machines (Injector line, Linac and Booster). The goal is to increase the proton flux by doubling the Booster beam cycle rate while maintaining the same intensity per cycle, the same uptime, and the same residual activation in the enclosure. For the Linac, the main focus within PIP is to address reliability. One of the main tasks is to replace the present hard-tube modulator used on the 200 MHz RF system. Plans to replace this high power system with a Marx-topology modulator, capable of providing the required waveform shaping to stabilize the accelerating gradient and compensate for beam loading, will be presented, along with development data from the prototype unit.