Quote:
Originally Posted by leviterande
It would be valuable to know whether the detector works also at other directions than perpendicular to earth surface. I stumble always upon this feat-that it needs to be directly above the source- in many pre WWII books. dont get me wrong. having a low flying plane with this device on board and flying over a suspect area over all the rocks, soil lakes and trees and get accurate data regardless of the terrain is really extremely helpful and wonderful but it is not to be compared with the ability to "point-scan" and area, i.e. stand in a forest, aim the device forward and rotate around you left or right until you find a signal.
Actually the "point+scan" ability should work just as well for the Bickel device. If point and scan does not work than, this means something big and important, (unnoticed by many) and perhaps confirming one cruicial point one more time during my research: those so called gamma radiations of the atom that are detected are not coming from the atom, they are coming from outer space. rays of extreme penetration imparting earth and all of its elements interacting with the atom. Obviously the highest penetration happens at 90 degrees from surface. Lots of materials indicate this as well or Something close to this. These are called vertical beams emanating from all elements. And that is what dowsers feel.
Nothing is written in stone yet though
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Hi leviterande,
In order to know whether the gamma isotope detector works in other directions, you must first understand what it is sensing. This machine detects gamma rays entering into the open end of a lead tube. This open tube end shields gamma rays from entering at the sides, so what you are sensing is basically a cone pattern that looks like the light pattern that a flashlight sends out. The cone angle can be narrow or wide, depending on how deep the scintillator crystal is embedded into the tube. For sake of discussion, let us assume a 10 degree cone angle which gamma rays can enter the end of the tube and pass into the detector crystal to be detected.
Now, more important than the cone angle of the sensor is the source of the gamma rays. These gamma rays are emitted from a gold atom in the ground when it a nuclide from radioactive decaying material (usually much deeper in the ground) collides with a gold atom. However, gold is fairly rare in the ground as a percentage of earth material, so only small traces of gamma rays come from the lumps of gold metal and gold veins found naturally in the ground. Fortunately there are a number of chemical processes which actually corrode gold and most other metals in trace amounts and cause ions of these metals to leach into the soil and disperse so they will occupy a larger volume of ground than the original gold metal that is buried. Over a very long period of time, the gold ions (or other metal ions) that are leaching out of the metal will begin to rise in a vertical column toward the surface of the ground. This leaves a trail of gold ions dissolved in the ground to form a vertical column directly above the buried metal. This vertical column has been measured to continue toward the surface for gold deposits that are buried up too 5000 feet deep. Now, if you consider a plot of ground that has a number of buried gold objects scattered in various amounts across the land, we would have a number of vertical columns of gold ions above a number of gold deposits. Because of the geometry of these ion columns, a radioactive nuclide is much more likely to collide with gold ions in the columns than the original metal gold deposits, which are much smaller. But regardless of how the nuclide collides with a gold atom, whether it is part of a metal lattice or an ion, the same gamma rays are emitted in greater amounts from the larger target area of this long column of gold ions above the gold metal.
Then we look at the directional properties of the gamma emissions from the columns and the actual gold metal at the bottom (which is actually a part of the column). If we make a traditional grid survey from above, we can expect the best precision, because the we are measuring from the top of many the columns where the contrast is expected to be better than if we measure at an angle. The length of this column dictates that it will focus the gamma emissions to come from a source only as wide as the column of gold ions. When we move our detector along the grid to a location that has no column of ions, then our readings drop to a normal background level for traces of gold that are not massive enough to create any sizable corrosion. Remember we are working with an assumed 10 degree cone angle of view, so we will have some loss of resolution when neighboring columns of ions are picked up within this cone of view.
Now suppose we use the probe with a point and scan technique. The first disadvantage is we lose the sharp contrast we had when we were sampling only from directly above the tops of these ion columns. If we measure the gamma count from the side of the column, we will see an anomaly which is not focused into a single point with the diameter of the top of the column. Instead, we will see the side of a column with a weaker signal strength, without any clear idea where to put the shovel until we do some vertical detecting to pinpoint the top. What the probe will be seeing in the horizontal scan position is the side of an ion column, and possibly the side of several other ion columns behind it or in front of it, as well as up to 5 degrees to either side. Yet with this loss of precision, it still may be useful for finding metals that have been buried a long time.
The problem of detecting the side of several columns can be mitigated by a person who is on foot by simply moving the probe around and tracking down the several columns from different angles. This seems not much harder than using a metal detector to find a small evasive item when you are digging. Another thing that can be done is to narrow the cone angle by extending the lead tube length to reduce the cone angle to maybe 5 degrees or less. This will improve the horizontal accuracy. But you will still need to move around and follow the target areas from different positions in your search field before you will pinpoint it. Of course, the final pinpointing would be done as a vertical scan across an area that is maybe 20-40 feet diameter to find where to put your shovel.
A final precaution: The gamma detectors are capable of detecting fresh metallic gold. But in practice, the users in the field say they only find gold that has been buried a long time (meaning 50 years or more). This points to the time it takes for the gold to corrode and traces of gold ions to leach into the soil and form the column of ions above the gold object. When treasure hunting, The gold treasures are much smaller than what geologists are looking for. Essentially the entire search plan is scaled down to micro size. Instead of finding an ion column anomaly that is 20 feet diameter above a ton of natural gold in rocks 500 feet deep, we are looking for a column on the order of 8" diameter and only as deep as the treasure is buried. This will require that the gamma detector is built with the best materials and designed to reject environmental noise, because the gamma anomalies we are trying to pick up are so much smaller than what geologists are looking for. Also consider there may be natural gold buried very deep that has raised the background gold ion count of the soil, so your treasure anomaly is only a small percentage of the total gold gamma signal you pick up. The fact that it is an anomaly should still be detectable, even with a high background count. But your biggest hazard is noise from solar/magnetic sources. How practical is this? I don't know. It depends on the cost of parts if you are a tinker who will build it yourself. Parts cost around $1200 back in the day when Dr. Bickel was building his state of the art machines. But today we have better parts, and they are cheaper for many of them. Instead of using discrete logic chips like he did, we can use a single logic module, or an asic to do the processing. The only high tech parts you need are the sodium iodide crystal and photomultiplier. Do not skimp on the scintillator crystal. The cheap ones don't compare to quality parts, and they stop working after a couple of years. There are also other scintillator sensors available today that were not available back then. Be sure you get something that will respond to the gamma from Au 196 and the resultant signal can be processed to discriminate the spectral data in your logic module.
Best Wishes,
J_P
P.S. If this "ion column" stuff sounds weird to you, it did to me too until I read how it is a muilti-million dollar industry to find gold, copper and other metals at minesites. Read here for more about that:
http://www.longrangelocators.com/for...3&postcount=29
There are links at the bottom that will lead you to some amazing discoveries in the past 20 years about things happening to metals in the ground.