At 01:31 PM 6/3/2012, Martin wrote:
I'd like to see the business about the null radiation readings clarified. It seems to me BB are getting different types of meters and different types of radiation readings all mixed up.
Me too. I'm sure he meant though areas where there were no readings and areas with pockets too.
They don't say what the college professor's detector was, but presumably it was a common-or-garden Geiger-Muller tube. They call it a "Geiger counter". Hmm , on the other hand they all the one BB used a Geiger counter, too, but I don't think it was, so that may mean nothing! But an output in cpm (counts per minute) does indicate a Geiger counter, so that seems clear. A Geiger tube just counts particles, not energies, so doesn't identify types of radiation or give "dose" information directly . (I just noticed the professor's article in the file where he identifies it as a Geiger counter, specifically a Model 2612 Portable Survey Meter.)
With the beta shield on it measures gamma rays. The V-700's I used in the MADAR project were beta-gamma discriminators. We also had a scintillator with used a sodium iodide crystal and was 60x's more sensitive.
Then BB talk about their own "Geiger counter" - which is not actually a Geiger counter at all, but a "Model 2586 Beta-Gamma Survey Meter". This was a low-voltage ionisation chamber detector of a different type, advertised as "true roentgen indicator" because it does not output a simple particle number in cpm but a dose value in milliroentgens that only applies to X-ray and gamma radiation readings, not to alpha and beta particle readings. This is why the BB report shows the readings they took at the site only in "mr/hr" or milliroentgens per hour.
The V-700 geiger counter, for example, has both scales. The clicks and counts per minute are calibrated as mr/hr also. When gamma rays strike the geiger tube the ionized gas lets the 600 volts jump the gap and cause a click there but it is extremely brief. Geiger counters measure mostly beta and gamma radiation.
The military had/has devices just like our 700's, and my adviser that once worked for Project SIGN, Lewis Blevis, helped design these and his resume in the 1960's called them RADIAC.
Interesting points I'd like to inject here:
1) Mass effect. You have to know the area and get readings AFTER the incident by at least days or weeks. Every area has its own background radiation. If only one reading is taken you don't have anything in most cases. When they shaved a hill at Vincennes to put up the Red Skelton Bridge we measured the BG and it was so high we almost burned up the scintillator. That was the normal shale reading!
2) Directionality. In the movie (1952) War of the Worlds, the geiger counter in their prospector's jeep was clicking when they were parked near the gulley where the craft had landed. Gene Berry grabbed the probe and swung it toward the gully and the reading increased, then decreased when he turn around in the other direction. Bad science used in this movie. Radiation decreases or decreases at the inverse square of the distance, not by aiming the geiger probe.
In fact BB's machine can't detect alpha particles at all [I 've just noticed that Prof Gehman mentioned this same point already! I really should have read the whole file before starting this post, but I'll press on!) .
This depends on their energy. An alpha particle that comes from nuclear decay is usually only able to travel a short distance, a few centimeters, through air. (We's get this from isotopes used for calibration). Alpha particles as cosmic rays, however, are much more energetic, and can penetrate quite deeply, even through many meters of solid shielding. These can penetrate the atmosphere. But we never condsidered alpha in anything we did.
BTW, not to clutter the issue at hand, wait until you see the Keenes Case or Wayne City incident our NICAP investigated in 1963. Got a real mystery there because the Air Force was there and they got readings on the Austin boy's car.
The Geiger tube, if fitted with the right type of mica window, can do so. So that's a basic difference. And then BB confuses cpm and mr/hr. They asked their radiation specialist Major Sproul for comment on a reading of "60,000 mr / per hour" taken by the professor on Dec 30 (nine days after the sighting), and he told them that there should still have been a high level there on Jan 12.
That's 60 roentgens per hour. If correct that is equivalent to heavy nuclear fallout or a bad meter. Some isotopes could be that high for a short time.
Guys, I've always had trouble with potential ET cases and residual radiation. Even WE don't leave this kind of pollution laying around and I doubt somebody way ahead of us would have a propulsion system that was that dirty.
But this assumed equivalence of cpm and mr/hr is out by 2 or 3 orders of magnitude! A typical conversion - it's approximate and depends on sensor size and calibration - is in order of 1,000 cpm per mr/hr ( e.g. http://www.hps.org/publicinformation/ate/q4148.html). So 60,000 cpm actually only equals a few tens of mr/hr.
I gotta take a break on this one because I haven't even read the report <GRIN>. Bear with me guys.
Add to this the fact that the prof's Geiger counter (if used close enough to the ground, as Prof Gehman said it was - the probe was "trailed in the grass") could possibly have been detecting (in part) alpha particles that the Beta-Gamma Survey Meter could not even see, and BB's null radiation result (nothing above background) looks completely useless. Indeed the only values they give are not from the site at all but from someone's watch and the wing of a car that had driven there. This is just stupid. But if these readings are also supposed to be indicative of the "background" at the site then it was very high - about 30 times the typical value.