[en] The design study of a low energy neutral particle analyser by using the time of flight method is performed. The chopper system can be made by a modified turbo molecular pump. A modified photo-electron-multiplier with a gate assembly may be suitable for the detector of this system. If a turbo molecular pump can rotate with a speed of about 40000 rpm, then the energy resolution (δE/E) of 1 keV hydrogen particles is less than 20% with the flight length of 2 m (It is assumed that the chopper radius is 50 mm and the width of a slit is 0.15 mm). (author)