[Prev][Next][Index][Thread]

Re: Thoriated Tungsten


Might want to turn on the AC.

 ----------
|From: "tesla-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|To: Benson Barry; "Tesla-list-subscribers-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|Subject: Re: Thoriated Tungsten
|Date: Tuesday, October 01, 1996 3:12AM
|
|<<File Attachment: 00000000.TXT>>
|From rwstephens-at-ptbo.igs-dot-netMon Sep 30 22:03:52 1996
|Date: Mon, 30 Sep 1996 00:07:46 -0500
|From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
|To: tesla-at-pupman-dot-com
|Subject: Re: Thoriated Tungsten
|
|>>From ed-at-alumni.caltech.eduSat Sep 28 21:36:18 1996
|>Date: Sat, 28 Sep 1996 15:21:59 -0700 (PDT)
|>From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
|>To: Tesla-list-subscribers-at-poodle.pupman-dot-com, tesla-at-pupman-dot-com
|>Subject: Re: Thoriated Tungsten vs Pure
|
|>Thoriated tungsten is used for tube filaments because it hnas
|>has much higher emission at lower temperatures than pure tungsten,
|>hence lasts much longer.  Effect was discovered accidently in the
|>early 1920's.  Thorium was originally added to light bulb filaments
|>"to make them easier to draw through the wire dies" (per RCA
|>Vaccum Tube Design Manual, circa 1940).
|>Can't prove it, but suspect the radioactivity is barely detectable,
|>and certainly not a health hazard.
|>Ed Phillips
|<snip>
|
|Ed, All,
|
|You are quite correct.  The ionizing radiation level at the surface
|of these thoriated tungsten TIG rods is barely above background.
|
|I have a geiger mueller civil defence type counter , Anton
|Electronics, CD V-700 Model No.5.  It measures MR/HR in three ranges.
|The lowest (X1) range is 0 to 0.5 MR/HR.  The pickup tube is in a metal
|cylinder like a microphone.  There is a Gamma filter shield which you can
|rotate
|open to detect lower power Beta particles.  With this shield open, 
background
|barely lifts the needle from the bottom stop at ~ 0.03 MR/HR.  When I
|place 10 of those thoriated tungsten rods in a bundle right against
|the detector I get a reading of 0.25 MR/HR.  When I hold the detector
|to the plastic face of a WWII vintage radium painted Solar watch I
|have it goes crazy reading 17 MR/HR (1/3rd up the X100 range).
|
|I don't think you'd develop radiation ralated problems if you sprinkled the
|dust from grinding these on your food every day for 30 years.  I
|suspect you'd probably suffer intestinal distention from heavy metal
|accumulation.  But you'd be a quicker quencher, and you wouldn't
|overheat. :-)
|
|By the way, these civil defence geiger counters are just the thing
|next to an alarm clock for your bedside table.  Seriously!  After the
|alarm awakens you, just check the GM machine.  If its emitting a
|cacophony and pegging the scale, just hit the ol' super snooze alarm.
|On this day you might as well sleep in!
|
|Regards,
|
|rwstephens
|
|
|