As with all electrode based light sources the colour quality and luminous efficiency of the light changes dramatically as the electrodes burn away during use. And the tungsten lamp, which is similar to the classic incandescent domestic version, but with an extra high-temperature filament so that it gives high illumination and high colour temperature for the price of a short lifetime. In nearly all cases solar simulators using a combination of these old technologies can only represent part of the solar spectrum at the same time and many have extremely elaborate and vulnerable reflector and filter systems to simulate the Sun’s radiation at all wavelengths.

With Plasma International Lighting Systems there are none of these risks or problems, the spectral output is truly full and continuous, not just for hours, but for years, with no qualitative or quantitative degradation.

There are currently 2 variations of the plasma lamp available, the Standard Sulphur lamp (SS0) and the Triple A class Solar Simulator lamp (AAA).

A Simplified Perspective from Clive Wing:

The SS0 lamp has hardly any UV light and less red light than the AAA lamp that the Dutch researchers have named the Artificial Sun.

Spectral Match – How close it is to the power of visible and invisible colours that are in sunlight.
Non-Uniformity of irradiance - How evenly spread out (distributed) it is.
Temporal Instability – How constant the output is.

A New way of Measuring is Needed

We can not claim higher luminous efficiency than a sodium lamp or higher PAR (Photo synthetically Active Radiation) than a metal halide or sodium lamp because when we measure our plasma lamp in lumens or micro moles it nearly always measures at least 30% less than other HID lamps of the same wattage. We will claim a higher PUR (Photo synthetically Useful Radiation) value because we believe the plasma lamps that we manufacture are the only lamps that are truly a full and continuous spectrum and thus, completely unlike LED's, deliver all of the light that is useful for photosynthesis.

Conventional methods of measuring light for humans use lumens, deemed useless for horticulture, horticulturists measure light in micro moles (µmoles). Working with British, German and Dutch horticulturists and researchers I have learnt that micro mole measurements are the best indicator we have at this time. The results from real world tests indicate that a plasma lamp, that measures 30% micro moles 'less' than a High Power Sodium Lamp of same wattage, produces at least 30% more biomass, and can fully grow cucumbers to European standards 10 days sooner. After eating them myself I can confidently write that in my opinion cucumbers grown in continuous full spectrum light with a low PAR value, compared to HPS, have better aroma, flavour and colour. My hunch is that the nutritional value will be far higher also, especially as thinking it will be the same is disregarding the principles of logic!

A solar simulator is now measured as class A, B, or C for Spectral Match, Non-Uniformity of Irradiance, and Temporal Instability of Irradiance. Solar simulators utilizing plasma-i lamps are easily designed to meet Class A performance for all 3 of the test requirements.

The three standards that define solar simulator performance, in order of most demanding parameters first:

• JIS C 8912-1998, Solar Simulators for Crystalline Solar Cells and Modules
• IEC 60904-9 Edition 2 (2007) Photovoltaic Devices – Part 9: Solar Simulator
• Performance Requirements
  ASTM E 927-05 (2005) Specification for Solar Simulation for Terrestrial PV Testing