[Milsurplus] X-Ray Damage.. more

[Bob Camp]

Hi

I must have missed the first post in the thread. The fact that they  
are microphones was something I missed.

A lot of microphone elements are parabolic in their force to  
electricity characteristic. At "zero" they do not produce a useful  
response. To make them work you "polarize" the element with a high  
voltage. It's  a one time process, and normally heat is also involved.  
Sounds like yours got a bit to much ....

I'm a little surprised that they do the polarization after mount  
though. I alway assumed they did it to the bulk material .....

Bob


On Oct 26, 2007, at 11:06 PM, J Forster wrote:

> Hi,
>
> The pic I saw clearly showed damage from an arc or something like  
> it. It
> was burnt. Also, as I remember, crystal microphones are not made out  
> of
> quartz (it's far too stiff) but rather something like KDP or Rochelle
> salt.
>
> -John
>
>
> Bob Camp wrote:
>
>> Hi
>>
>> Unless the crystal was made from swept quartz (and thus is a  
>> "weapon")
>> it will turn a nice dark black when you shoot it with a lot of x- 
>> rays.
>> You can radiate them up into the megarad region without doing
>> mechanical damage.
>>
>> EMP's have very little effect on a crystal. A crystal simply does not
>> get enough energy from the pulse.
>>
>> Most shipping damage on crystals is pretty simple - somebody hit it
>> with more shock than it could handle.
>>
>> The only crazy way to bust one is to hit it directly with a whole lot
>> of DC. Enough voltage can peal the electrodes right off of the  
>> crystal
>> element. It still doesn't produce mechanical damage.
>>
>> Bob
>>
>> On Oct 26, 2007, at 5:32 PM, J Forster wrote:
>>
>>> I was sent a pic of a damaged crystal elements that originated this
>>> thread and it looks far to severe for something incidental to an X-
>>> Ray.
>>> It looks like there was an arc inside the case, so it seems possible
>>> that someone along the shipping is exposing the packages to an EMP.
>>> The
>>> reasons for such exposure are obvious and likely justified by some
>>> 'homeland security' cover.
>>>
>>> If such is the case, it may have more impact on the international
>>> trade
>>> in electronic items by individuals that the elimination of surface
>>> shipping last spring.
>>>
>>> I'd be interested to hear of other examples
>>>
>>> Best,
>>> -John
>>
>
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