X-Message-Number: 3363 Date: 29 Oct 94 15:54:44 EDT From: yvan Bozzonetti <> Subject: SCI.CRYONICS : Brain scanning: Brian's idea Answer to Brian Wowk's message 3360. Brian Wowk having given up on MRI, Braginsky's quantum nondemolition and x-ray vaporization of brains, the case for brain scanning looks in good way to be largely accepted. I was so ready to let the case for low energy x-ray holography to B. Wowk. My ideas was to send a personal answer and give a copy on request at all interested reader (I assume there would be few of them). I have done so and my general answer to message 3360 can be sent. But I can't stop here because a new fact has entered into play: Reading Brian message, I stumbled on an extraordinary statement: " >>>> This absorption will occur even if your x-rays are so monochomatic that they have coherence length of kilometers. <<<< The photoelectric effect doesn't care about coherence." Current technology, outside the nuclear one, alows only at most some millimeter coherence length, to produce a hologram of a large object as a brain, length on the meter scale are needed and I stopped here without looking beyond. A litle nervous, Brian pushed far more outside that limit. Indeed, on a theoretical ground, nuclear systems can produce kilometer long coherence length and then something extraordinary happen: the so called tunnel effect. For nontechnical people, I explain what is the coherence length for both, a classical and a quantum wave: In the classical case, coherence is defined only for a wave by looking at another wave. In the simplest case there will be two wave oscillating on parallele lines at nearly the same frequency. If these waves are in phase at some place, they will remain so for some distance, until the wavelength difference builds up to half a wavelength. At this place, there will be no coherence anymore. This is coherence length as it applies to waves on a water pond for example. In a quantum case, things are very different. A very monochromatic photon has a well defined energy, with nearly no uncertainety. But the product of that energetic uncertainety by the time one must be equal, at least to a physical constant , the so called reduced Planck's constant. A very monochromatic photon is so time blurred and that translates into position uncertainety. Indeed, the displacement from some initial position is simply the product of time by the photon velocity. The space blurring of the photon is simply its coherence length or put in another way, the length of the wave packet associated to the photon. There is no need to look at a second photon, this is an intrinsic property of the photon. All of that is elementary quantum mechanics explaned in all textbooks on the subject at the chapter on Heisemberg's uncertainety principe. Now, when a wave encounter some absorbing material, it don't drop out to zero instantly, it travel some distance inside the obstacle and this one is not too thick it can get out on the other side. A photon is not a wave but a wave packet with wavelength extending at least at the coherence length. A x-ray photon with coherence length in the kilometric range contains so a kilometric wave and this one can alows it to pass an obstacle less than some kilometers wide. A brain, whatever its absorptive properties is ten thousands times smaller than the longest wave in the wave packet so that the photon has vanishingly small probability to be stopped inside it. this is the so called tunnel effect. To summarize, kilometers long coherence lengths have a very strong effect on absorption properties, such waves would travel in a brain nearly without creating radiation effects. A scanner based on this system could be used on a living brain many times without risk. This is a conceptual break through. The basis of a brain reading paradigm. I assume Brian Wowk was not concious of that, but its subconcious may have worked on, how to accept othervise a so mindless forget of basic quantum mechanics? I suggest to call this system a Wowk's scanner. Don't give up Brian! Write without restrain, but read again after: you may discover some tresure in your texts. Whatever, thank you for breaking my mind wall about properties of very long coherence waves, without you, I think i was able to miss the aim for years. You have said the solution to brain scanning must not be searched in the ionising radiation domain. I give you the mark, yes, x-ray must be turned into nonionisig radiations before use. Classical holography may not be the best solution, I give up on that, the Wowk's scanner is far more better. Now we have to look at the detector problem... Have you some ideas? Yvan Bozzonetti. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3363