IPAC2011 - List of Authors (Drumm, B.S.)

Paper	Title	Page
TUPC147	A Micro-Channel Plate Based Gas Ionization Profile Monitor with Shaping Field Electrodes for the ISIS H⁻ Injector	1371
	P.G. Barnes, G.M. Cross, B.S. Drumm, S.A. Fisher, S.J. Payne, A. Pertica, C.C. Wilcox STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	Beam profile measurements within the ISIS H⁻ injector line are achieved using destructive devices such as moving wire scanners. To avoid damage to the wires, measurements are made with the injector operating on reduced power. This paper reports the development of a Micro-Channel Plate based profile monitor which allows beam measurements to be made under normal operating conditions. The monitor produces profiles by measuring the +ion current resulting from the interaction of the H⁻ beam with the surrounding residual gas. The 32 channel Micro-Channel Plate is mounted on a rotating arm to enable it to be positioned parallel to the beam for calibration (all channels then measure the same +ion current) and perpendicular to the beam for profile measurements. A 15kV drift field is used together with field shaping electrodes to ensure a flat electric field gradient across the monitor, thereby minimising distortion of the profile due to the electric field. This paper details all aspects of the design and construction of this profile monitor. Beam profiles are compared to previous wire scanner results. Shaping field upgrades are discussed to improve the longitudinal field shape.

Paper

Title

Page

A Micro-Channel Plate Based Gas Ionization Profile Monitor with Shaping Field Electrodes for the ISIS H⁻ Injector

1371

P.G. Barnes, G.M. Cross, B.S. Drumm, S.A. Fisher, S.J. Payne, A. Pertica, C.C. Wilcox
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Beam profile measurements within the ISIS H⁻ injector line are achieved using destructive devices such as moving wire scanners. To avoid damage to the wires, measurements are made with the injector operating on reduced power. This paper reports the development of a Micro-Channel Plate based profile monitor which allows beam measurements to be made under normal operating conditions. The monitor produces profiles by measuring the +ion current resulting from the interaction of the H⁻ beam with the surrounding residual gas. The 32 channel Micro-Channel Plate is mounted on a rotating arm to enable it to be positioned parallel to the beam for calibration (all channels then measure the same +ion current) and perpendicular to the beam for profile measurements. A 15kV drift field is used together with field shaping electrodes to ensure a flat electric field gradient across the monitor, thereby minimising distortion of the profile due to the electric field. This paper details all aspects of the design and construction of this profile monitor. Beam profiles are compared to previous wire scanner results. Shaping field upgrades are discussed to improve the longitudinal field shape.