In hot plasma research the hardware which allows to measure absolute flux and mass/energy spectra of neutral particles is widely used. The analysis of neutral flux allows to acquire in a direct way the parameters of plasma ions such as ion temperature and percentage of ion species.
An extensive experience is amassed in Atomic Collisions Department of IOFFE Institute in design of various types of neutral particles analyzers (NPA). A wide choice of NPAs allows to perform the adequate measurements under variety of experimental conditions and goals. A short list of main NPA features is given below.
- The energy range. There are NPAs for low, middle and high energies. The total energy range is very wide – from tens of electron volts up to several mega electron volts. The energy setup can be fixed or adjustable.
- Mass analysis. Simultaneous energy spectra measurement of several hydrogen, helium isotopes is possible. Mass suppression reaches values of 1:1000.
- Ionization (stripping) of neutral particles. Two stripping methods are used – in gas and in a thin carbon foil. Gas stripping is more appropriate for low energies. If energy of the particle is sufficiently high ( >1 keV) then foil stripping becomes preferable.
- Detector type. Regarding experimental conditions most optimal detectors are used. These could be channel electron multipliers, photomultipliers, solid-state detectors. The last two types of detector allows to make additional amplitude analysis of NPA signal. This increases mass suppression and signal-to-noise ratio of NPA.
- Insensitivity to high radiation background. A lot of noise is produced in NPA detectors by radiation fields (neutrons and gamma-rays) during operation of large thermo-nuclear experimental devices. Additional detector-screening measures implemented in the NPAs let them operate under neutron fluxes of up to 108 neutrons/cm2/s.
- Multi-line measurements. Pinhole type NPA was developed to allow multi-line measurements.
In close cooperation with the Atomic Collision Physics Laboratory, Technoexan Ltd carries out the manufacturing and the delivery of NPA for customers. Up to date over twenty NPAs of different types were shipped to plasma research centers in the USA, Germany, France, UK, Spain, Switzerland, Japan, China.