[AMPS] Re:

[Jon Ogden]

>I dont know for sure, but suspect the most likely candidates are
>magnetic resonance imaging (MRI), or to give its its old name, nuclear
>magnetic resonance (NMR) - the latter being dropped, as the word
>'nuclear' alarms people.

>From what I knew NMR and MRI are similar but 2 different technologies.  
Of course I could be wrong too.  NMR I thought was used more for material 
research while MRI was more for diagnosis of human patients.  

> As for makes, I dont know many, but Seimens and
>GE are two I can think of.. I would add that the NMR systems we have
>where I work, all have semiconductor power amps, with *peak* powers of
>about 1 kW. Average powers are *much* lower. Quite why such large tubes
>are used I dont really know, but I know they are indeed used.  I'll ask
>around - we have several experts on MRI around here. Perhaps its just a
>case of very conservative rating.

Picker is another MRI manufacturer.

The strength of the amp depends on the strength of the magnetic field 
generated.  The frequency of the amp also depends on the strength too.  A 
2 Tesla system (the strongest that I know of) operates around 64 MHz.  
For the 2T system, I want to say it goes as high as 20 KW, but then that 
might be too high (7 KW also comes to mind).  Anyhow, it's much higher 
than 1 KW for the bigger systems.  And yes, average power is very low on 
these.

73,

Jon
KE9NA


-------------------------------------
Jon Ogden
KE9NA

http://www.qsl.net/ke9na


"A life lived in fear is a life half lived."


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