The neutral particle analyzer with energy and mass selection capability built for JET is described. The analyzer is able to detect in the same shot both H atoms from 0.3 to 320 keV and D atoms from 0.15 to 160 keV. In order to optimize the ion optics of the analyzer an oblique entrance in the magnet has been chosen. An ion trajectory code shows that in this way a good mass separation and a high efficiency can be achieved. The problems inherent in the analyzer calibration for a wide energy range are discussed, and the calibration procedure is described. In conclusion, the calibration results obtained with five analyzers are presented, together with theoretical consideration on ion optics and atomic processes, which have enabled us to write a simple interpolation formula for the experimental data.