A cylindrical mirror analyser for neutrino mass measurement

The design of an electrostatic Cylindrical Mirror Analyser (CMA) for neutrino mass measurement is given. The resolution is 15 eV FWHM, being achieved with second order focusing and tight collimation. The field-matching grids are unique, being sets of accurately positioned vertical wires producing negligible resolution effects. Luminosity is maximised with an extended source and by utilisation of the full 2π of the CMA. Background is minimised as the deflecting voltage is half the analysing energy so that field-emission can be discriminated against. Cosmic-ray secondaries are largely removed by high resolution silicon surface barrier detectors. The construction of the CMA to an accuracy of ∼ 10 eV in base resolution, and of the magnetic shielding and vacuum systems is outlined. The power supplies and monitoring systems, signal processing electronics and data acquisition software are also described. Monte-Carlo simulations indicate that with this optical resolution, knowledge of molecular final states and energy loss, a lower limit of 10 eV (95% CL) should be measured for a neutrino mass of 30 eV with a suitable source. For a zero neutrino mass an upper limit of 20 eV (95% CL) would be obtained. (author)