Browse Prior Art Database

Monitored Evaporant Source

IP.com Disclosure Number: IPCOM000094420D
Original Publication Date: 1966-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Roberts, GC: AUTHOR [+2]

Abstract

In apparatus for vaporizing and depositing material, a sensing device for monitoring the vaporization rate is placed in the gas stream.

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Monitored Evaporant Source

In apparatus for vaporizing and depositing material, a sensing device for monitoring the vaporization rate is placed in the gas stream.

A pair of heated U-shaped resistance elements is positioned across the vapor stream to be monitored. The temperature of element 1 is made higher than the temperature of the other element 2. Thus, there is a net thermionic emission which is modified by the vapor stream. The voltage developed by this current on load 3 controls a reactor in the circuit between the power source and the heater to adjust the heating current.

The heater, the shields and the charge are subject to a bias. On the other hand, the sensing circuit is floating with respect to ground. This bias prevents drift in the sensing circuit and reduces sensitivity to heater temperature.

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