ORNL, Oak Ridge, Tennessee, USA
The SNS linac utilizes several accelerating structures operating at different frequencies and with different transverse focusing structures. Low-loss beam transport requires a careful matching at the transition points in both the transverse and longitudinal axes. Longitudinal beam parameters are measured using four Bunch Shape Monitors (in use at many ion accelerator facilities, aka Feschenko devices). These devices, as initially delivered to the SNS, provided an estimated accuracy of about 5 picoseconds, which was sufficient for the initial beam commissioning. New challenges of improving beam transport for higher power operation require measuring bunch profiles with 1-2 picoseconds accuracy. We have successfully implemented a number of improvements to maximize the performance characteristics of the delivered devices. We will discuss the current status of this instrument, its ultimate theoretical limit of accuracy, and how we measure its accuracy and resolution with real beam conditions.
ORNL RAD, Oak Ridge, Tennessee, USA
ORNL, Oak Ridge, Tennessee, USA
A new system for measuring the SNS ion beam longitudinal profile was recently upgraded to operational status. The hardware for this device was developed and delivered by Institute for Nuclear Research to the SNS as a part of its initial construction. The supplied LabVIEW user interface software was intended for proof-of-operation and initial setup of the instrument. While satisfactory for this, it was tedious to use in a practical context and lacked any form of interface to the SNSs EPICS based control system. This paper will describe the software features added to make this instrument both easily tunable to the prevalent beam conditions by system engineers and easily usable by accelerator physicists only interested in its output data.