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: Whooa!! X-ray city!
Date: Jun 24, 01:19 am
Poster: Richard Hull

On Jun 24, 01:19 am, Richard Hull wrote:

I have repaired my fusor III view port, by placing in a new glass.

Tonight, as I was tuning the puppy to hit the 20kv neutron voltage, (takes hours on mechanical systems), I checked for X-radiation, as always, once I cruise over 15KV applied.

This new window was a nice suplus 1/4" thick glass disk of unknown composition. (I thought it might be pyrex like the last glass) The normal level of X-radiation appears inline with, and normal to, the window as was found in the original port. (mentioned in February postings)

However, an intense and ultra-narrow beam sweeps out a 360 degres circle or disk in the PLANE of the glass window disk. A calibrated Victoreen type Cutie-Pie ionization meter detected up to .1 roentgen/hr at the edge of the glass disk (point contact @ 20kv applied).

At 2 feet, the 20kev beam is about 5-10mr/hr. Using a .5" windowed gieger tube. I was able to detect the thin radiation beam disk out to 12 feet! At this range, the beam appears not to have diverged at all. The width of the beam is under 1/2" as moving the counter tube only its diameter, laterally, virtually eliminates all counting.

This is a vast change from virtually zero radiation in this region from the original window.
This may be a hunk of lead glass!! It seems to be sealing well and standing up under the 100 deg C temperatures. I found that a simple 6" X 4" X 1/4" lead plate placed against the fusor port in front of the operator, will completely shield to the point of background.

Again, check for X radiation at every run. It just makes good sense.

Richard Hull