Independent testing has revealed a large advantage of Aware Electronics Radiation Monitors over and above many of our competitors. With high level rising radiation fields, as would occur near a nuclear incident, the Aware monitors continue to display increasing viable radiation readings while the competitor’s radiation monitors display a falling radiation level and finally read zero radiation levels. This fall-off to a zero reading occurs at a radiation level 1000 times less than levels where the Aware monitors continue to display rising radiation levels.
The testing was performed using a precision digital readout microfocus spot X-Ray probe tester. Radiation levels were confirmed using a RAD-CHECK PLUS X-ray Exposure Meter.
Summary of the test:
Normal Monitor 4 and Inspector type radiation monitors quit (read zero) at below 0.001 R/H. (Totally saturates at 9.5 uA beam current).
Aware Electronics radiation monitors work (do not saturate) to at least 1.42 R/H, which is the strongest radiation field the microfocus spot X-Ray probe tester could generate.
Aware Electronics monitors include an exclusive discriminator which allows the accurate display of radiation levels well in excessive of what one would expect given the tube data sheet. When developing our circuit, we designed and tested several hundred variations and finally settled on the best performing. All active components are rugged silicon devices very resistant to radiation and burn-out. Power draw is ~ 0.08ma at background levels and rises very modestly with very high radiation fields. The circuit operates with input voltages anywhere between 2VDC to 20 VDC. The fully regulated high voltage section maintains a constant high voltage with extremes of input voltage and radiation levels. The resulting design represents an entirely original circuit available exclusively in Aware's monitors.
An important part of any Geiger counter circuit is the high voltage generator. Most of Aware’s competitors use a very simple technique to generate the high voltage known as a boost converter. This involves an inductor in series with a transistor switch and a diode. The transistor is turned on and off by a control circuit. An advantage of the boost converter is it does not utilize a custom step-up transformer but rather utilizes a very simple and cheap inductor.
We have analyzed various competitor boost converters with an oscilloscope and notice they subject the transistor to repeated voltage spikes near or even above their absolute maximum rating. This can lead to degradation and breakdown of the transistor over long periods of time even if operated somewhat below the absolute maximum rating. Even a competitor’s boost converter with a four stage diode multiplier generating 500 VDC, produces 200+ volt pulses on the transistor.
Aware Electronics Corp. uses a different technique for generating the high voltage necessary. We have custom designed a miniature high voltage transformer which includes three windings, a primary, secondary and feedback winding, allowing us to create our unique, fully regulated very high efficiency high voltage harmonic oscillator power supply.
Aware's harmonic oscillator utilizes the natural rhythm of the transformer’s inductance and a capacitor to step-up the low voltage source to a high voltage by-way-of the turns ratio of the primary to secondary. The primary winding of our transformer includes approximately 8 turns and the secondary includes over 2000 turns, thereby stepping up the voltage needed with just two diodes, even with a 1.5 volt input. (Input voltage can range from 1.5 to 20 VDC). Aware's new HV harmonic oscillator is also very low noise due to the transformer's primary winding tank circuit.
All active components of the high voltage generator are rugged bipolar silicon devices, including the components in the regulating sub-system. Many competitor systems utilize mosfets which can be very sensitive to voltage spikes.
A high-voltage n-p-n--n+ type power transistor switching an inductive load for approximately 1000 hours showed no significant variation in the electrical parameters. Infrared scanning, and cross-sectioning and visual inspection of the chip indicated a crystal damage at the n--n+ interface under the center of the emitter. Transmission electron microscopy (TEM) investigations revealed the crystal damage to consist mainly of silicon phosphide precipitate platelets surrounded by dislocation loops and dislocation clusters. An analysis using a two-dimensional mathematical model predicts high electrical and thermal stresses at the damaged location of power transistor during its switching applications.
Click here for a Comparison of Aware Electronics Corp. LCD-90 + RM-80 to the Mazur PRM-9000
Aware Electronics RM-60 Versus Digilert: Aware Electronics RM-60 Versus Digilert
We have analyzed a Geiger counter by SparkFun: A look at SparkFun Geiger Counter
We have tested software by others and are surprised by the results. Click here to read about it: A look at a system by others
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