HIGH SENSITIVE BEAM EMITTANCE ANALYZER

A new computer-controlled beam emittance analyzer was developed at Neue Technologien Gelnhausen (NTG). The emittance meter is a ready-to-use system consisting of a 45o slit and wire-grid profile system for measuring transversal beam emittances and beam profiles. The main new feature is the highly sensitive current measurement electronics (SME), which consists of 32 precision, low-noise, integrating amplifiers with FET op-amp, switchable integrating capacitors, and low leakage FET. They integrate the low-level input currents in parallel during a measurement period specified by the user, and the resulting voltages are read out from the integrating capacitors. Because of the very low noise and low input leakage current, measurements of currents in the order of pA are viable. The input signal current may be positive or negative. The channel capability is expandable to 128 wires in each of the two planes. An emittance beam analyzer has been installed at the ISOLDE off-line separator at CERN. In this article the design, the electronics and the newly developed software is explained, and the first results are presented.