Page 2 of 3

Operating principle A schematic diagram and a photograph of CNPA-M is shown in Fig.5.2. It is an NPA of E||B scheme.  The  accelerator is used for a better collection of secondary ions scattered in the stripping foil. The NPA dispersion system was specially designed for the focusing of ions at the detector area. A shape of magnet poles and a shape of electrostatic condenser plates were simulated by computer modeling which included the particle trajectory calculations. The detector unit consists of two channeltron rows coinciding with H and D mass detection lines.

The Low and High energy  modifications of  analyzer look very similar to CNPA-M. The  stripping cell of CNPA-L, which  uses the gas stripping method, is located in place of stripping/acceleration unit.

CNPA advantages

  • CNPA-M as well as CNPA-H has no gas inlet therefore it does not affect the vacuum conditions in plasma machine.

  • CNPA uses permanent magnets which do not require any power supply.

  • CNPA has high detection efficiency.

  • CNPA can be (optionally) equipped with

    - built in accelerator and electrostatic condenser power supply;

    - built in preliminary data acquisition system.

  • CNPA is very compact. Therefore it is easy to arrange a multichord diagnostic system using the set of such spectrometers.

Fig.5.2a Schematic diagram of Compact NPA.

  

Fig.5.2b Photograph of Compact NPA.

Some of the major components labelled are:  (1) stripping/acceleration unit (or stripping unit for CNPA-L); (2) stripping foil; (3) analysing magnet; (4) Hall probe; (5) analysing electrostatic condenser; (6) detector mask; (7) detector array; (A0) atomic flux emitted by plasma; (A+) secondary ions.

< Back

Next >

Home