Following my arguments for X-ray generation, I have done my first experiment to prove or otherwise disprove the theory that EHD thrusters/lifters are creating a background radiation imbalance around them, by generating very short wavelength highly energised radiation. Although the power of such radiation is by far too small to cause the experienced lift on these devices, harmful X-ray radiation in air cannot be ruled out. The experiment was done with my old faithful Dielectric coated flat panel thurster, having the positive terminal connected to the foil and a self developing X-ray photo sheet, the same as commonly used by your dentist.
This photo shows the developed X-ray photo on the left and the plastic pocket which was hanging within the thruster during the test. During exposure, the photographic paper is held in this pocket. Two stainless steel washers of 2mm thickness were glued onto this pocket, one on each side, so that a resulting image would be transfered on the photo, in case of X-ray band radiation. As you see on the left developed image, the photographic paper has been indeed exposed to some kind of ionisation. This result may be an indication that the lifter does indeed radiate in the X-ray band, and at high enough operating voltage, it should radiate even in the Gamma band - tested by JLN Gamma radiation test. The Gamma radiation tests show that Gamma radiation from a lifter compares to background radiation and is not hazardous.
A close up of the developed photo reveals the radiation emissions in the X-ray band. The exposure time was 8 minutes, with the photo in close proximity to the aluminium foil of the thruster, powered at about 50 Watts / 60 kV. As can be seen, the rays have penetrated through the 2 mm stainless steel washers in many parts. However, it is also noticed that areas that should have been easily exposed on the same photo, have not been exposed, and this could mean that the result shown on this photo cannot be conclusive, as other effects (not X-ray) could have resulted in the chemical reaction upon the photographic paper. For this purpose, more sophisticated measuring devices have to be employed for conclusive results.
Negative radiation tests- by Willy Guns
For this experiment, a Scintillation meter Type 540, an NaI-detector, a Series 900 mini-monitor with Geiger Muller counter and an ESM FH 40 G-L (0.1 microSv/h - 25 mSv/h (35 keV - 1.3 MeV) were used. Tests were performed with a Silicium-Lithium detector diameter 3 inch with Berillium window (without lead screen protection), with a preamplifier and Canberra S40 and S50 Multichannel-analysers. This resulted in a background radiation reading ten times normal. The thruster was setup at 45 mm in front of the detector window. Below are photos of experimental setup at the VUB (Free University Of Brussels).
The following curve shows the test results obtained for Pb lead (dark blue), Al aluminium lifter-element (purple) and the background radiation (light blue) levels for the range from 5 keV to 300 keV.
Result, no or negligible radiation when the EHD thruster is operated at 30 kV in air. Further experiments with my Geiger-Muller counter based on military spec GM tube 8767, and with an NaI detector, also gave no positive results.
This experiment definetely shows that