Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Microwave experimentation safety precautions
Date: Jul 30, 7:57 pm
Poster: Jim Lux

On Jul 30, 7:57 pm, Jim Lux wrote:

>I think that for safety reasons it would be sensible to put any such apparatus in a closed wire cage (something called a Faraday cage which can be made out of any good conductor - copper wire mesh is traditional) to block any microwave leaking from the apparatus.

DO NOT USE WIRE MESH TO (try to) SHIELD MICROWAVES.. The woven nature allows the power to go right through. the power is carried on the strands from one side to the other.

Look closely at your microwave oven: that is PERFORATED METAL.. which is much much different than woven mesh.

I second Richard's comments about microwave energy.. The power density coming out of a typical magnetron is spectacularly high. Eye and thyroid tissues are a) close to the skin, b) good absorbers, and c) have a very low damage threshold.

Say you shield your box with 50 dB isolation (which is doing quite well with a casual design).. you still have 10 milliwatt leaks. And if that leak is near the window port where you put your eyes to look into the chamber...

Insulating HV is easy by comparison with providing suitable shielding for high power microwave sources. Microwave ovens may look simple, but a lot of engineering time went into making them radiologically safe.