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.

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