Re: Electrometer insulators (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 30 Oct 2006 21:46:33 -0800
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>, hvlist <hvlist@xxxxxxxxxx>
Subject: Re: Electrometer insulators (fwd)

At 08:27 PM 10/30/2006, High Voltage list wrote:

>---------- Forwarded message ----------
>Date: Mon, 30 Oct 2006 20:09:18 -0500
>From: Richard Hull <rhull@xxxxxxxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Re: Electrometer insulators (fwd)
>
>Sapphire is the normal super insulator of choice in high end electrometer
>work.  Polystyrene and teflon are about an equal #2.
>
>Richard Hull

One also usually wants low noise as well as high resistivity. 
Sapphire is good, PS and PTFE are good.  I've been given to 
understand that there are some ceramics (alumina) that work well 
(after all, sapphire is just alumina).  Lead glass is apparently 
quite quiet, but has lower resistivity.

Apparently, there aren't any good current manufacturing sources for 
other useful parts like 1 Teraohm low noise resistors.