Sublimated titanium as a gettering agent in conjunction with a turbine-type pump provides a two-step procedure for obtaining an ultrahigh vacuum of 10 to the minus 11 torr. The pump alone evacuates the chamber to a pressure of 10 to the minus 9 torr. The residual gas is removed by the gettering agent at a pumping speed of 15 liters per second per square inch

Outlaw, R. A.

English

NASA Technical Reports Server

September 1966	 Brief 66-10388 
NASA TECH BRIEF 	
a 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Auxiliary Titanium Sublimation Pump Produces Ultrahigh 
(10-11 Torr) Vacuum 
	
Chamber	 Titanium Filaments
Coolant
Coolant 
Titanium 
Sublimation Pump 
	
Hot-Filament	 ,.' Bakeable Chamber Valve 
Cold-Cathode Gage
	 Bleed Valve	 .	 ,Turbo Molecular Pump 
To Mechanical Pump 
The problem: 
To develop a simple, ultrahigh vacuum pumping 
system for research studies of residual gas ana-
lyzers and vacuum gages. The system must not re-
quire continuous attention in the course of producing 
an ultimate pressure of 10- 11 torr. 
The solution: 
The use of sublimated titanium as a gettering agent 
in conjunction with a turbine-type (molecular drag) 
pump. The latter pump alone will evacuate the cham-
ber to a pressure of 10-9 torr. The residual gas, 
mostly hydrogen, is removed by the gettering agent at 
a pumping speed of approximately 15 liters per second 
per square inch. This combination provides an easy 
-	
-	 (continued overkaf) 
two-step procedure for obtaining an ultrahigh vacuum 
of 10 — 11 torr. 
How it's done: 
The titanium sublimation pump is separated from 
the turbine pump by a bakeable valve. This separation 
prevents backstreaming of the turbine pump vapors 
at pressures lower than 1 x 10- 10 torr. Initially the 
turbine pump evacuates the chamber to a pressure of 
5 x 10- 8
 torr. After a bakeout at 400°F, the bakeable 
valve is closed and the titanium filaments are heated 
to sublimate the titanium on the cooled chamber sur- 
face. The hydrogen and other gases are adsorbed on 
the coated surface, and the ionic action of a cold- 
cathode gage supplements the pumping of gases not 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000387 2020-03-11T17:36:01+00:00Z
readily adsorbed by the titanium. Three additional 
one-minute sublimations are required to reach 1 
x 10 —I1 torr, and a sublimation is required every 
three days to maintain this pressure level. Total pump-
down time to obtain this pressure was five days after 
the valve was closed. 
Notes: 
1. The use of a cryogenic coolant in the chamber 
jacket shortens the pumpdown time, but its effect 
decreases as the chamber pressure drops. 
2. The lowest pressure indication obtained with this 
system was 7 x 10- 13 torr.
3. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Langley Research Center 
Langley Station 
Hampton, Virginia 23365 
Reference: B66-10388 
Patent status: 
No patent action is contemplated by NASA. 
Source: Ronald A. Outlaw 
(Langley-212) 
Brief 66-10388	 Category 02


Auxiliary titanium sublimation pump produces ultrahigh /10 to the minus 11 torr/ vacuum

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