Pulsed NMR magnetometers for CESR

The Cornell Electron Storage Ring (CESR) has recently begun an operating program spanning a wide energy range, from 1.5 to 5.4 GeV. Wide-range magnetometers are necessary for accurate control of the bending fields. These have been implemented using the principal of pulsed nuclear magnetic resonance (NMR). The required field range has been achieved by using a high impedance preamplifier in the field probe to isolate the detection coil, and resonating the coil with high-ratio tuning diodes. A probe installed in a CESR standard bend magnet has been operated continuously from 350 to 2450 gauss using water as the resonance medium, and a second probe in a high field bend magnet has been operated from 860 to 6725 gauss, also using water.