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452. Some problems of obtaining and maintaining pressures below 10−9 torr in large metal vessels
Classified A b s t r a c t s 4 5 0 - - 4 5 6
Classified A b s t r a c t s Abstracting Editor's Note The label tmmedmtcly following the title of each item denotes country of ortgm of pubheatlon, and that at the end o f each abstract indicates country of ortgm of work (where known)
General Vacuum Science and Engineering 10.
V a c u u m S c i e n c e and T e c h n o l o g y
cross-section is t h e s a m e for H e a n d N e T h e a u t h o r investigated this f o r m u l a experimentally over the p r e s s u r e r a n g e 5-10 torr a n d f o u n d satisfactory a g r e e m e n t It is s u g g e s t e d t h a t t h e m e t h o d is preferable to t h e r m a l c o n d u c t i v i t y m e t h o d s m case of g a s m i x t u r e s of very different a t o m i c weights ( U S S R ) w J s
10
450. Progress in the ultra-high vacuum field. (I) Principles, methods of measurement and measuring instruments. (Germany) E A T r e n d e l e n b u r g , Phys Blatt, 19 (10), Oct 1963, 463-470
11.
V P C h e b o t a r e v , Prlbory t Tekhmka Expertmenta, 2, 1963, 176-177
Production of Low Pressures 14.
ll
Kinetic Theory of Gases
451. Progress in ultra-high vacuum field. (II) Pumping methods.
14
(Germany)
Brttam) 11
452. Some problems of obtaining and maintaining pressures below 10 9 torr m large metal vessels. (U S S R ) T h e a u t h o r describes t h e p r e c a u t i o n s required to m a i n t a i n a stainless steel vessel of 0 4 m 3 capacity at a p r e s s u r e o f 2 × 10 10 t o r r T h e v a c u u m w a s o b t a i n e d by m e a n s o f a m e r c u r y v a p o u r p u m p fitted with two h y d r o g e n t r a p s a n d s o r p t l o n o f the residual g a s with t i t a n i u m o n a s u b s t r a t e kept at liquid n i t r o g e n t e m p e r a ture T h e e v a c u a t i o n rate per m 2 was o f t h e o r d e r o f 1051/sec T h e rate o f e v a p o r a t i o n o f t~tanIum n e c e s s a r y for m a i n t a i n i n g this rate is d e t e r m i n e d by t h e ratio o f the n u m b e r of molecules of t i t a n i u m e v a p o r a t e d per unit time to t h e n u m b e r o f molecules of h y d r o g e n e n t e r i n g the v o l u m e in t h e s a m e t i m e F o r the installatlon u n d e r test, t h e o p t i m u m value of this ratio was of the o r d e r o f 12 (USSR) w J s E A M a s l e n n l k o f f et al, Prlbory t Tekmka Expertmenta, 5, 1963, 148-156
12.
Measurement of Low Pressures 12
21
454. The mechanism of gas trapping during ion pumping. (Great
E A T r e n d e l e n b u r g , Phys Blatt, 19 (12), D e c 1963, 550-553
22
The application of the Atlas quadrupole mass spectrometer type A M P 3 for partial pressure measurements m high vacuum systems. See A b s t r N o 495 12
453. Measurement of gas pressures by means of electron scattering.
(USSR)
T h e a u t h o r Investigated t h e p o s s i b l h t y o f m e a s u r i n g t h e p r e s s u r e o f a h e h u m - n e o n m i x t u r e f r o m t h e a m o u n t of scattering experienced by an electron b e a m traversing the m i x t u r e The m e t h o d consists of c o m p a r i n g t h e c h a r g e received by a special collector electrode, at a given gas p r e s s u r e with t h a t u n d e r h i g h v a c u u m c o n d i t i o n s w h e n n o scattering t a k e s place If I a n d L) are t h e c u r r e n t s u n d e r p r e s s u r e P a n d v a c u u m c o n d i t i o n respectively, it c a n be s h o w n t h a t
A n e x p e r i m e n t is described w h i c h s h o w s u n e q u i v o c a l l y t h a t gas t r a p p e d in glass d u r i n g ion s o r p t t o n ts held in a s p e c t r u m o f c a p t u r e sites o f v a r y i n g b i n d i n g energy O p e r a t i o n of an i o n p u m p elevated t e m p e r a t u r e s s h o w e d t h a t s u b s e q u e n t release o f the p u m p e d gas is only effected by h e a t i n g the p u m p to h i g h e r than operating temperature (Great Britain) (Author) G P S m e a t o n , et al, Brtt J Appl Phw', 15 (2), F e b 205-207
1964,
14
10
455. A new apparatus for the analysis of heterogeneous gas processes and its application for the investigation of the kinetics of adsorption, desorption and diffusion phenomena on solids.
(Germany) In order to m e a s u r e d e g a s s l n g a n d a d s o r p t i o n rates, the pressure in the v o l u m e is controlled by the pulsed o p e n i n g o f a valve which is g o v e r n e d by a pressure g a u g e F o r m e a s u r i n g d e g a s s i n g rates, the valve c o n n e c t s t h e c h a m b e r with the p u m p i n g s t a t i o n a n d in the reverse case wlth t h e gas supply T h e n u m b e r of valve o p e n i n g s per unit time is registered Since t h e v o l u m e of the v a c u u m c h a m b e r is k n o w n , the n u m b e r o f valve o p e r a t i o n s will indicate the a m o u n t o f the e x c h a n g e process In this m a n n e r all p a r a m e t e r s which are I m p o r t a n t for the investigation o f h e t e r o g e n e o u s gas processes, s u c h as d u r a t i o n o f t h e process, e x c h a n g e rate a n d a m o u n t of the e x c h a n g e d gas, c a n be o b t a i n e d It is possible to set t h e p r e s s u r e r a n g e between o p e n i n g a n d closing the valve so n a r r o w t h a t the process c a n be investigated approximately under constant pressure conditions Another a d v a n t a g e of this s y s t e m is t h a t investgiat~ons c a n be m a d e over a very large r a n g e o f d e g a s s i n g rates W i t h this m e t h o d a large n u m b e r of investigations of a d s o r p t i o n , d e s o r p t l o n a n d diffusion p h e n o m e n a o n solids were p e r f o r m e d with P i r a n l - m a n o m e t e r s as pressure controls (Liechtenstein) (Author) T h K r a u s , 2nd European Vie Symp, 5-7 J u n e 1963, 245-251, (R A L a n g Verlag) 14
15
456. The accurate measurement of gas flow rates. (Germany)
P ~ C × logelo/l
T h e q u a n t i t y o f gas r e m o v e d f r o m a s a m p l e o f (sohd) material c a n be d e t e r m i n e d with great accuracy, if a m e t h o d 1s avadabl¢
T h i s a s s u m e s t h a t the electron speed is s u c h t h a t the scattering 209
Classified A b s t r a c t s Abstracting Editor's Note The label tmmedmtcly following the title of each item denotes country of ortgm of pubheatlon, and that at the end o f each abstract indicates country of ortgm of work (where known)
General Vacuum Science and Engineering 10.
V a c u u m S c i e n c e and T e c h n o l o g y
cross-section is t h e s a m e for H e a n d N e T h e a u t h o r investigated this f o r m u l a experimentally over the p r e s s u r e r a n g e 5-10 torr a n d f o u n d satisfactory a g r e e m e n t It is s u g g e s t e d t h a t t h e m e t h o d is preferable to t h e r m a l c o n d u c t i v i t y m e t h o d s m case of g a s m i x t u r e s of very different a t o m i c weights ( U S S R ) w J s
10
450. Progress in the ultra-high vacuum field. (I) Principles, methods of measurement and measuring instruments. (Germany) E A T r e n d e l e n b u r g , Phys Blatt, 19 (10), Oct 1963, 463-470
11.
V P C h e b o t a r e v , Prlbory t Tekhmka Expertmenta, 2, 1963, 176-177
Production of Low Pressures 14.
ll
Kinetic Theory of Gases
451. Progress in ultra-high vacuum field. (II) Pumping methods.
14
(Germany)
Brttam) 11
452. Some problems of obtaining and maintaining pressures below 10 9 torr m large metal vessels. (U S S R ) T h e a u t h o r describes t h e p r e c a u t i o n s required to m a i n t a i n a stainless steel vessel of 0 4 m 3 capacity at a p r e s s u r e o f 2 × 10 10 t o r r T h e v a c u u m w a s o b t a i n e d by m e a n s o f a m e r c u r y v a p o u r p u m p fitted with two h y d r o g e n t r a p s a n d s o r p t l o n o f the residual g a s with t i t a n i u m o n a s u b s t r a t e kept at liquid n i t r o g e n t e m p e r a ture T h e e v a c u a t i o n rate per m 2 was o f t h e o r d e r o f 1051/sec T h e rate o f e v a p o r a t i o n o f t~tanIum n e c e s s a r y for m a i n t a i n i n g this rate is d e t e r m i n e d by t h e ratio o f the n u m b e r of molecules of t i t a n i u m e v a p o r a t e d per unit time to t h e n u m b e r o f molecules of h y d r o g e n e n t e r i n g the v o l u m e in t h e s a m e t i m e F o r the installatlon u n d e r test, t h e o p t i m u m value of this ratio was of the o r d e r o f 12 (USSR) w J s E A M a s l e n n l k o f f et al, Prlbory t Tekmka Expertmenta, 5, 1963, 148-156
12.
Measurement of Low Pressures 12
21
454. The mechanism of gas trapping during ion pumping. (Great
E A T r e n d e l e n b u r g , Phys Blatt, 19 (12), D e c 1963, 550-553
22
The application of the Atlas quadrupole mass spectrometer type A M P 3 for partial pressure measurements m high vacuum systems. See A b s t r N o 495 12
453. Measurement of gas pressures by means of electron scattering.
(USSR)
T h e a u t h o r Investigated t h e p o s s i b l h t y o f m e a s u r i n g t h e p r e s s u r e o f a h e h u m - n e o n m i x t u r e f r o m t h e a m o u n t of scattering experienced by an electron b e a m traversing the m i x t u r e The m e t h o d consists of c o m p a r i n g t h e c h a r g e received by a special collector electrode, at a given gas p r e s s u r e with t h a t u n d e r h i g h v a c u u m c o n d i t i o n s w h e n n o scattering t a k e s place If I a n d L) are t h e c u r r e n t s u n d e r p r e s s u r e P a n d v a c u u m c o n d i t i o n respectively, it c a n be s h o w n t h a t
A n e x p e r i m e n t is described w h i c h s h o w s u n e q u i v o c a l l y t h a t gas t r a p p e d in glass d u r i n g ion s o r p t t o n ts held in a s p e c t r u m o f c a p t u r e sites o f v a r y i n g b i n d i n g energy O p e r a t i o n of an i o n p u m p elevated t e m p e r a t u r e s s h o w e d t h a t s u b s e q u e n t release o f the p u m p e d gas is only effected by h e a t i n g the p u m p to h i g h e r than operating temperature (Great Britain) (Author) G P S m e a t o n , et al, Brtt J Appl Phw', 15 (2), F e b 205-207
1964,
14
10
455. A new apparatus for the analysis of heterogeneous gas processes and its application for the investigation of the kinetics of adsorption, desorption and diffusion phenomena on solids.
(Germany) In order to m e a s u r e d e g a s s l n g a n d a d s o r p t i o n rates, the pressure in the v o l u m e is controlled by the pulsed o p e n i n g o f a valve which is g o v e r n e d by a pressure g a u g e F o r m e a s u r i n g d e g a s s i n g rates, the valve c o n n e c t s t h e c h a m b e r with the p u m p i n g s t a t i o n a n d in the reverse case wlth t h e gas supply T h e n u m b e r of valve o p e n i n g s per unit time is registered Since t h e v o l u m e of the v a c u u m c h a m b e r is k n o w n , the n u m b e r o f valve o p e r a t i o n s will indicate the a m o u n t o f the e x c h a n g e process In this m a n n e r all p a r a m e t e r s which are I m p o r t a n t for the investigation o f h e t e r o g e n e o u s gas processes, s u c h as d u r a t i o n o f t h e process, e x c h a n g e rate a n d a m o u n t of the e x c h a n g e d gas, c a n be o b t a i n e d It is possible to set t h e p r e s s u r e r a n g e between o p e n i n g a n d closing the valve so n a r r o w t h a t the process c a n be investigated approximately under constant pressure conditions Another a d v a n t a g e of this s y s t e m is t h a t investgiat~ons c a n be m a d e over a very large r a n g e o f d e g a s s i n g rates W i t h this m e t h o d a large n u m b e r of investigations of a d s o r p t i o n , d e s o r p t l o n a n d diffusion p h e n o m e n a o n solids were p e r f o r m e d with P i r a n l - m a n o m e t e r s as pressure controls (Liechtenstein) (Author) T h K r a u s , 2nd European Vie Symp, 5-7 J u n e 1963, 245-251, (R A L a n g Verlag) 14
15
456. The accurate measurement of gas flow rates. (Germany)
P ~ C × logelo/l
T h e q u a n t i t y o f gas r e m o v e d f r o m a s a m p l e o f (sohd) material c a n be d e t e r m i n e d with great accuracy, if a m e t h o d 1s avadabl¢
T h i s a s s u m e s t h a t the electron speed is s u c h t h a t the scattering 209