Using muons to see through pyramids, underground caverns and even into the cores of dangerous volcanos and nuclear reactors is not a new idea. However such devices are well outside the budget of most individuals or organisations needing to do research or to mitigating potential hazards.
Here is the real challenge of the AMC project, creating something that is relatively affordable for anyone to make.
Fast moving high energy muons created in the upper atmosphere rain down across the entire surface of the surface of the earth. They do this continuously at approximately 200 muons per second, per square metre. When counting muons over time the average flux is nearly uniformly and isotopic varying little over time, other than small gradual variations during the solar magnetic cycle every 11 years.
Consequently, when averaging muon flux over time from a specific direction, it is unlikely it will be any different to any other angle. Except where it is passing through different densities of matter like a mountain.
To achieve this aim, I'm using low-cost Si Pin Photodiodes in a stacked array to create a virtual collimator to focus muons signals only coming from one direction. Then grouping these detectors into an array is very similar to that of a compound eye used by butterflies and other arthropods.
Muons only weakly interact with matter and are only slightly affected by strong magnetic fields or passing through very dense materials. Consequently, they cannot be focused like conventional camera lenses.
One way of focusing high energy particle is to use a collimator, which is a device made from a dense material like lead (Pb). Particles that travel parallel to the aperture of the collimator pass through while others traveling at an angle are absorbed into the dense side walls.
The apposition muon camera, focuses muons coming from one direction using a virtual collimator with an array Si Pin of Photodiode particle detectors stacked one above the other, where the signal from each detector is added together using a voltage summing operational amplifier. Consequently, when a muon travels directly through all the individual detectors simultaneously in the array, it will have the highest signal amplification. Whereas, muons or local background radiation passing through at other angles will be at a lower amplification and can be filtered or used for angular information as is done in an a compound eye of arthropods.
Possible 4 x 4 array configuration
Theoretical image after processing of the summed count rates spanning a number of week/days on each virtual collimator detector stick showing a possible caverns or thick dense material concealed inside a mountain.
This design is not solely limited to use as the AMC:
- As it could also be used individually as a single cosmic ray telescope.
- In a small coincidence bundle like I have used in my Cosmic Array art project ( the impetus that created this new design).
- In other linear array configurations using raster scanning methods or,
- Meridian drift scanning for an "all of sky" muon mapping.
The design also lends itself to be arranged into a flat matrix of Si Pin Photodiodes and used as a beta, gamma and X-ray monitoring. Also enhanced with the...Read more »