However, for gamma radiation, the generator head is one thing, and changing the time it is on, or changing the kilovolts running through the primary circuit will in fact cause either more gamma rays to emit, or in fact change the power of penetration of each ray, thus the intensity is variable. The dosiometer badge will in fact measure that, as it picks up the amount of gamma rays striking a particular place (the film in the badge).
The gamma rays pass through the subject, and the shadow of the object is what is recorded on the pickup screen, no doubt a digital screen in this case.
Changing colors of stuff out in the yard depends on the stuff. Color change can occur due to oxidation, or molecular breakdown of the components of the surface of the material. This can occur due to (mostly) ultraviolet, but also the entire spectrum of electromagnetic radiation.
If you cannot bezaddle with brilliance, then baffle with bullshit, eh?
OK, I guess I did not explain the concept clearly. Thanks for trying to stay with me; I’ll try again to explain. As for your part, you are not succeeding in either bedazzling me or baffling me, so I’m not 100% sure as to what you were referring with the last line of your last post.
I am NOT an expert on the Rapiscan scanners. No one outside the company, and perhaps the TSA, is an expert on these devices. I do NOT have inside knowledge on how they work. However, some aspects of their operation seem to be clear from general physical principles.
Firstly, note that the Rapiscan scanners are referred to as “scanners.” Scanning is NOT the same thing as a simple irradiation. Scanning refers to acquiring an image pixel-by-pixel or line-by-line. You may have a document scanner on your desk, for example; if so, you may wish to notice that the device probably delivers light to one line of a page at a time, images that line, then moves the light / sensor array, and images the next line. The overall energy delivery used for the acquisition of the whole image may be low, but, at any moment, the section being acquired is intensely illuminated.
Here’s another backyard example to illustrate the difference between regular illumination and scanning. Consider a group of ants in the sun. They can stay in the sun indefinitely, and be quite happy doing so. Now imagine a magnifying glass between the ants and the sun. By concentrating the sun’s energy on a smaller area, a hot spot can be created that is lethal to ants. The total amount of energy delivered to the group of ants is the same with and without the magnifying glass in place (actually, it’s a little less, since a real magnifying glass doesn’t have perfect transmittance), but the effect of the energy differs between with or without the glass in place.
In this example, moving the glass around (scanning) from ant to ant can lead to the rapid demise of all the ants — using no more energy than they would have absorbed just relaxing in the sun, were that magnifying glass not present.
A simple dosimeter in place of the ants would detect only the overall energy delivered through the glass. If the focus of the magnifying glass was scanned over the dosimeter (again, this is a simple dosimeter, not engineered to pick up intensity readings) then the dosimeter would react exactly as if the glass had not been in place. The ants, however, would still be dead.
Again: intensity matters. Intensity can’t be detected by all the same technologies (such as dosimeter badges) which detect other characteristics of radiation.
Also, there’s the fact that the Rapiscan backscatter scanners do NOT work by measuring gamma rays passing through a subject. Rather, contrary to your post, the Rapiscan backscatter scanners work by measuring, well, backscatter. The physics of the relatively high-energy wavicles that produce images via transmittance are slightly different than the physics of the lower energy wavicles that are used for backscatter images. Again, another analogy. I admit that this analogy may be wrong because neither I, nor anyone else in the general public, knows the operating parameters of the Rapiscan devices. However, the overall outlines of the analogy are likely correct.
So here’s the analogy: a standard X-ray passes through tissue like a high-speed, pointed-tip, non-hollow-point bullet. The backscatter device uses X rays that don’t pass through the body as much, more like a blunt bullet, or perhaps a hollow point. I am NOT trying to turn this thread into a gun thread, so I am NOT trying to say that hollow point bullets are deadlier than non-hollow points or vice versa. What is indisputable, however, is that, all other things being equal, the hollow-point bullet causes damage in a different pattern than the non-hollow point bullet.
In this case, we know the effects of the damage done by “non-hollow point bullets” (penetrating X-rays). We do NOT have the same knowledge about the damage done by “hollow-point bullets” that dump more of their energy at the skin (X-rays used by the Rapiscan Scanners). The X-rays used by the Rapiscan Scanners are an unknown quantity, in terms of their ability to cause cancer in the structures they do hit. The “hollow-point bullets” may be more dangerous than “non-hollow-points,” may be less dangerous, or, for all we know, may actually increase the health of the people who are exposed to them. Thing is, WE DO NOT KNOW, and our knowledge about how the “non-hollow-point bullets” work is only minimally helpful in predicting the effects of the “hollow-points.” It’s a pretty sure bet, however, that, if you wanted to maximize SKIN damage, you would choose “hollow-points” over “non-hollow-points.”
Now, the bullet analogy seemed to me a good way to illustrate the point, but, now that I’ve written it, I have a feeling this whole thread is going to wind up on the bang list, and the responses will soon include references to Glocks vs. Rugers vs. Colts. Sigh. Well, I’ll try to keep up. Thanks for reading.