Re: What medicinal equipment uses HV caps?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net> 

Tesla list wrote:
>Original poster: Kreso Bukvic <kreso.bukvic-at-kc.htnet.hr>
>All say x-ray? i contacted Siemens x-ray service i Croatia and they say that
>there is no cap in x-ray only a potted cascade ( shimatsu the second and
>last x-ray service in Croatia also said this )! All sellers of maxwells say
>it is from medicinal equipment and that what equipment i ask you?
>
>.

Kreso,

HV filter caps are sometimes used in X-Ray systems to provide more precise 
"band" of X-ray energy than can be provided by an AC system that uses 
half-wave self-rectification (one pulse) or full-wave rectifiers (two 
pulse). Powerful machines often use three phase power and 6 or 12 pulse 
rectification. However, if these caps are used in a large X-Ray system, 
they are invariably filter capacitors using Mylar dielectric, and they are 
NOT rated for RF duty. Some inexpensive or mobile X-ray systems may 
discharge a capacitor bank through the primary of a step-up transformer in 
order to generate a high voltage pulse for X-ray generation. However, these 
capacitors are often banks of electrolytic capacitors.

True pulse capacitors ARE used in the Pulse Forming Networks (PFN's) inside 
medical Linear Accelerators (LINAC's). The PFN's are switched by a hydrogen 
thyratron to generate high voltage pulses (~50 kV) which inject a "bunch" 
of electrons into a linear accelerator (in a part of the accelerator called 
a buncher!). The bunch of electrons is then accelerated to a high velocity 
inside a specially designed linear cavity by microwave radiation from a 
Magnetron or Klystron. The accelerated electrons exit other end of the 
cavity as pulses of high energy electrons. These relativistic electrons are 
either used directly ("electron mode") or collided with a dense metal 
target to generate X-radiation ("photon mode"). In either case, the braking 
of the high speed electrons within the patient, or within the intervening 
metal target, generates X-radiation for various types of radiation 
treatment (typically for cancer).

And, pulse caps are also used in defibrillators for jump starting or 
resynchronizing fluttering hearts.

Happy hunting and best regards,

-- Bert --
--------------------------------------------------------------------
We specialize in UNIQUE items! Coins shrunk by Ultrastrong Fields,
Lichtenberg Figures (electrical discharges in acrylic), & Scarce OOP
Technical Books. Stoneridge Engineering -- http://www.teslamania-dot-com
--------------------------------------------------------------------