ASTM E834-21

Standard Practice for Determining Vacuum Chamber Gaseous Environment Using a Cold Finger

SIGNIFICANCE AND USE
5.1 When applied in the case in which there is no test item in the vacuum chamber (such as during bake-out operations), this procedure may be used to evaluate the performance of the vacuum chamber in relation to other data from the same or other chambers given that critical parameters (for example, length of exposure, temperature of the chamber and cold finger, anisotropy, and so forth) can be related.  
5.2 The procedure can be used to evaluate the effects of materials found in the residue on items placed in the vacuum chamber.  
5.3 The procedure can be used to describe the effect of a prior test on the residual gases within a vacuum chamber.  
5.4 By selecting the time at which the coolant is introduced into the cold finger, the environment present during a selected portion of a test can be characterized. This can be used to determine the relative efficacy of certain vacuum chamber procedures such as bake-out.  
5.5 The procedure may be used to define the outgassed products of a test item that condense on the cold finger.  
5.6 The procedure may be used in defining the relative cleanliness of a vacuum chamber.  
5.7 In applying the results of the procedure to the vacuum chamber in general, consideration must be given to the anisotropy of the molecular fluxes within the chamber.  
5.8 The procedure is sensitive to both the partial pressures of the gases that form the condensibles and the time of exposure of the cold finger at coolant temperatures.  
5.9 The procedure is sensitive to any losses of sample that may occur during the various transfer operations and during that procedure wherein the solvent is evaporated by heating it on a steam bath.
Note 1: Reactions between solvent and condensate can occur and would affect the analysis.
SCOPE
1.1 This practice covers a technique for collecting samples of materials that are part of the residual gas environment of an evacuated vacuum chamber. The practice uses a device designated as a “cold finger” that is placed within the environment to be sampled and is cooled so that constituents of the environment are retained on the cold-finger surface.  
1.2 The practice covers a method for obtaining a sample from the cold finger and determining the weight of the material removed from the cold finger.  
1.3 The practice contains recommendations as to ways in which the sample may be analyzed to identify the constituents that comprise the sample.  
1.4 By determining the species that constitute the sample, the practice may be used to assist in defining the source of the constituents and whether the sample is generally representative of samples similarly obtained from the vacuum chamber itself.  
1.5 This practice covers alternative approaches and usages to which the practice can be put.  
1.6 The degree of molecular flux anisotropy significantly affects the assurance with which one can attribute characteristics determined by this procedure to the vacuum chamber environment in general.  
1.7 The temperature of the cold finger significantly affects the quantity and species of materials collected.  
1.8 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 23.160 - Vacuum technology
• Technical Committee: E21 - Space Simulation and Applications of Space Technology
• Drafting Committee: E21.05 - Contamination

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E834 − 21
Standard Practice for
Determining Vacuum Chamber Gaseous Environment Using
1
a Cold Finger
This standard is issued under the fixed designation E834; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope mine the applicability of regulatory limitations prior to use.
For specific warning statements, see Section 8.
1.1 This practice covers a technique for collecting samples
1.10 This international standard was developed in accor-
of materials that are part of the residual gas environment of an
dance with internationally recognized principles on standard-
evacuated vacuum chamber. The practice uses a device desig-
ization established in the Decision on Principles for the
nated as a “cold finger” that is placed within the environment
Development of International Standards, Guides and Recom-
to be sampled and is cooled so that constituents of the
mendations issued by the World Trade Organization Technical
environment are retained on the cold-finger surface.
Barriers to Trade (TBT) Committee.
1.2 The practice covers a method for obtaining a sample
fromthecoldfingeranddeterminingtheweightofthematerial
2. Referenced Documents
removed from the cold finger. 2
2.1 ASTM Standards:
1.3 The practice contains recommendations as to ways in E177Practice for Use of the Terms Precision and Bias in
which the sample may be analyzed to identify the constituents ASTM Test Methods
that comprise the sample.
3. Terminology
1.4 By determining the species that constitute the sample,
3.1 CFR, n—the residue collected by the cold finger during
the practice may be used to assist in defining the source of the
the vacuum exposure given in milligrams.
constituentsandwhetherthesampleisgenerallyrepresentative
of samples similarly obtained from the vacuum chamber itself. 3.2 cold finger, n—the device that is used in collecting the
sample of the residual gases in an evacuated vacuum chamber
1.5 This practice covers alternative approaches and usages
(see Fig. 1).
to which the practice can be put.
3.3 posttest stock sample residue mass, M,n—the mass of
f
1.6 The degree of molecular flux anisotropy significantly
residue in a sample collected from the cold finger during the
affects the assurance with which one can attribute characteris-
posttest operation and as measured by the technique specified
tics determined by this procedure to the vacuum chamber
in Section 9; the mass is based on a sample volume of 50 mL.
environment in general.
3.4 posttest stock sample residue mass, S,n—the mass of
f
1.7 The temperature of the cold finger significantly affects
residue in a sample of the solvent (used to obtain the posttest
the quantity and species of materials collected.
cold finger sample) as measured by the technique specified in
Section 9; the mass is based on a sample volume of 50 mL.
1.8 Units—The values stated in SI units are to be regarded
asstandard.Nootherunitsofmeasurementareincludedinthis
3.5 pretest cold finger sample residue mass, M,n—themass
i
standard.
of material collected from the cold finger during the pretest
operation and as measured by the techniques specified in
1.9 This standard does not purport to address all of the
Section 9; the mass is based on a sample volume of 50 mL.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.6 pretest stock sample residue mass, S,n—the mass of
i
priate safety, health, and environmental practices and deter-
residue in a sample of the solvent (used to obtain the pretest
cold finger sample) as measured by the technique specified in
Section 9; the mass is based on a sample volume of 50 mL.
1
This practice is under the jurisdiction of ASTM Committee E21 on Space
Simulation andApplications of SpaceTechnology and is the direct responsibility of
2
Subcommittee E21.05 on Contamination. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2021. Published April 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approvedin1981.Lastpreviouseditionapprovedin2015asE834–09(2015).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E0834-21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E834 − 21
containin
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E834 − 09 (Reapproved 2015) E834 − 21
Standard Practice for
Determining Vacuum Chamber Gaseous Environment Using
1
a Cold Finger
This standard is issued under the fixed designation E834; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers a technique for collecting samples of materials that are part of the residual gas environment of an
evacuated vacuum chamber. The practice uses a device designated as a “cold finger” that is placed within the environment to be
sampled and is cooled so that constituents of the environment are retained on the cold-finger surface.
1.2 The practice covers a method for obtaining a sample from the cold finger and determining the weight of the material removed
from the cold finger.
1.3 The practice contains recommendations as to ways in which the sample may be analyzed to identify the constituents that
comprise the sample.
1.4 By determining the species that constitute the sample, the practice may be used to assist in defining the source of the
constituents and whether the sample is generally representative of samples similarly obtained from the vacuum chamber itself.
1.5 This practice covers alternative approaches and usages to which the practice can be put.
1.6 The degree of molecular flux anisotropy significantly affects the assurance with which one can attribute characteristics
determined by this procedure to the vacuum chamber environment in general.
1.7 The temperature of the cold finger significantly affects the quantity and species of materials collected.
1.8 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific warning statements, see Section 8.
1.10 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1
This practice is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.05 on Contamination.
Current edition approved Oct. 1, 2015April 1, 2021. Published November 2015April 2021. Originally approved in 1981. Last previous edition approved in 20092015 as
E834 – 09.E834 – 09(2015). DOI: 10.1520/E0834-09R15.10.1520/E0834-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E834 − 21
2. Referenced Documents
2
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
3. Terminology
3.1 pretestCFR, cold n—finger sample residue mass, M —the mass of material collected fromresidue collected by the cold finger
i
during the pretest operation and as measured by the techniques specified in Section vacuum exposure given in milligrams.9. The
mass is based on a sample volume of 50 mL.
3.2 cold finger, n—the device that is used in collecting the sample of the residual gases in an evacuated vacuum chamber (see Fig.
1).
3.3 posttest stock sample residue mass, M —, n—the mass of residue in a sample collected from the cold finger during the posttest
f
operation and as measured by the technique specified in Section 9. The; the mass is based on a sample volume of 50 mL.
3.3 pretest stock sample residue mass, S —the mass of residue in a sample of the solvent (used to obtain the pretest cold finger
i
sample) as measured by the technique specified in Section 9. The mass is based on a sample volume of 50 mL.
3.4 posttest stock sample residue mass, S —, n—the mass of residue in a sample of the solvent (used to obtain the posttest cold
f
finger sample) as measured by the technique specified in Section 9. The; the mass is based on a sample volume of 50 mL.
3.5 cold finger—pretest
...