Path: utzoo!utgpu!watserv1!watmath!att!oucsace!oucsace.cs.ohiou.edu
From: bwhite@oucsace.cs.ohiou.edu (Bill White )
Newsgroups: sci.electronics
Subject: Can anyone identify these tubes?
Message-ID: <1624@oucsace.cs.OHIOU.EDU>
Date: 29 Jul 90 04:44:32 GMT
Sender: bwhite@oucsace.cs.OHIOU.EDU
Organization: Ohio U, home of the mighty Hocking River!
Lines: 33


	I happened to end up with two tubes that had originally been for
some sort of X-ray experiment, I think; I doubt if they are actually
X-ray tubes, but I think they might be detectors or some such.  In any case,
I want to know what they are:

1.	1P28 (or IP28, I'm not sure).  This has 11 pins, and the glass part
	is covered with some kind of black paint, save for a window in which
	I can see either a filament or a grid of some kind.

2.	Jarrell Ash Hollow Cathode Type 45439.  It also says "Cathode Na-K",
	"Max Current 25 ma", and "Gas NE".  And indeed, it is filled with
	neon, as a little experimentation shows.  Looking down into it,
	I see a squat cylinder open at both top and bottom, surrounded by
	what looks like metal deposition on the side of the tube (or maybe
	it's just from a getter).  Below the cylinder is a a long cylinder
	of metal (looks like sodium/potassium alloy, so I guess it's the
	cathode) with a hole stretching down the center.
	The entire tube looks a lot like a straight-necked "chimney" from
	an oil lamp, and the top is very flat.  The whole tube (glass, by
	the way) fits into a metal shield of some sort that has four holes
	about mid-way up the tube, plus is open at the front end.  There
	are two electrodes for this tube, the anode and cathode.

So, any idea?  If worse comes to worse, I can crack open the latter one for
the sodium-potassium alloy and drop it in the Hocking River, but I'd prefer
to know what these are actually _for_.


|   Bill White			Internet: bwhite@oucsace.cs.ohiou.edu	|
|	MURPHY'S EIGHTH COROLLARY:					|
|		It is impossible to make anything foolproof because 	|
|		fools are so ingenious.					|