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Performance characteristics of barium getters with particular reference to their application in thermionic valves
VACUUM Classified A b s t r a c t s
IV - -
Specxal
Subsidiary
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IV
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45 - -
0
ELECTRONICS
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Abstract No und Referene~ ~
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I o n Source U m t e d States A n Ion source is d e s c r i b e d to be used for t h e copious p r o d u c t i o n of i ons in an i s ot ope s e p a r a t i n g d e v i c e w h i c h IS s u i t a b l e for p r o d u c i n g i s o t o p e s on a c o m m e r c i a l scale of m a t e r i a l s such as c o p p e r - 6 3 a n d -65, c o b a l t - 5 9 a n d - 6 0 or u r a n i u m -234, -235, -237, - 2 3 8 The source of e l e c t r o n s c ons i s t s of a m a s s i v e t h l m b l e - h k e m a i n c a t h o d e , inside w h i c h is s u p p o r t e d a n a u x l h a r y - c a t h o d e , b o t h m a d e from t u n g s t e n A r o u n d t h e o u t s i d e of t h e m a i n c a t h o d e as p l a c e d a f i l a m e n t w h i c h is h e a t e d t o a t e m p e r a t u r e s u f f i c i e n t l y h i g h to i n i t i a t e e l e c t r o n e m i s s i o n from t h e m a i n c a t h o d e A source of a l t e r n a t i n g ~ o l t a g e IS c o n n e c t e d b e t w e e n t h e m a i n a n d a u x i l i a r y c a t h o d e W h e n e l e c t r o n e m i s s i o n from t h e m a i n c a t h o d e h a s be e n e s t a b l i s h e d t h e a l t e r n a t i n g v o l t a g e e ns ure s t h a t t h e arc d i s c h a r g e b e t w e e n t h e m a i n a n d a u x i l i a r y c a t h o d e IS m a i n t a i n e d , a n d t h e f i l a m e n t is t h e n s ~ l t c h e d off The e x t e r n a l s u p p l y c i r c u i t IS a r r a n g e d so t h a t t h e p o w e r i n p u t to e a c h of t h e e l e c t rode s c a n be c o n t r o l l e d I n d e p e n d e n t l y of t h e o t h e r e l e c t r o d e T h e a n o d e cons i s t s of a p l a t f o r m of t u n g s t e n rods p l a c e d n e a r t o t h e c a t h o d e s t r u c t u r e such t h a t t h e a u x i l i a r y c a t h o d e is s hi e l de d from t h e m a i n d i s c h a r g e b y t h e m a s s i v e e l fe c t of t h e m a i n c a t h o d e M e t a l is fed to t h e arc t h r o u g h a t ube , t h e end of w h i c h is d i r e c t e d t o w a r d s t h e a node p l a t fo rm T h e m e t a l is I n t r o d u c e d in t h e form of a wire or r i b b o n a n d m a y be c o n t m u o u s l 3 or i n t e r m i t t e n t l y fed I o n s p r o d u c e d an t h e m a i n d i s c h a r g e are d i r e c t e d Into t h e ion or i s ot ope s e p a r a t i n g dex ice b v a p p l i c a t i o n of a larg e negatlx e ~ o l t a g e to a c y l i n d r i c a l e l e c t r o d e p l a c e d c o a x i a l l y w i t h t h e arc c a t h o d e , b e t w e e n t h e l a t t e r a n d t h e i s o t o p e s e p a r a t i n g d e v i c e The whole source is m o u n t e d i n a v a c u u m c h a m b e r Somma*re On d o n n e des d 6 t a l l s sur une source d' Ion e m p l o y e e d a n s des a ppa re fl s s c p a r a t e u r s &Isotope, e x e c u t e s p o u r p r o d m r e des i s o t o p e s sur une echelle c o m m e r c l a l e
Method and Apparatus for Producing Ions U m t e d ~lates I s o t o p e s e p a r a t o r s , in w h i c h a b e a m of ions f o r m e d from t he e l e m e n t w hos e i s o t o p e s are to be r e s o l v e d IS b u n c h e d in a c c o r d a n c e w i t h t h e m a s s of t h e i ons p r e s e n t a nd t h e n d e f l e c t e d i n r f fields t o d i r e c t t h e p r e f e r r e d e n r i c h e d g r o u p s of ions i n t o a collector, r e q u i r e ion b e a m s of v e r y h i g h c o n t e n t before a s u b s t a n t i a l ield is o b t a i n e d Also, t h e ion source m u s t be c a p a b l e of c o n t i n u o u s o p e r a t i o n for a c o n s i d e r a b l e F e rl od A v a c u u m arc source, w h i c h fulfils b o t h t h e s e r e q u i r e m e n t s , Is d e s c r i b e d A hol l ow c3 l m d r m a l a n o d e m o u n t e d , w i t h its a x i s v e r t i c a l , a b o v e a flat i n d i r e c t l y h e a t e d a n o d e h a v i n g a c e n t r a l hole, is, in t u r n , s e t b e l o ~ a de~ ice for d r o p p i n g a s t e a d y s t r e a m of p o w d e r e d m a t e r i a l a x i a l l y t h r o u g h t h e a s s e m b l y Thi s p o w d e r is x apormed b y t h e r a d i a n t h e a t from t h e a n o d e a n d t h e gas is l o m s e d in t h e a rc A n y p o w d e r r e m a i n i n g falls t h r o u g h t he hole in t h e c a t h o d e , below w h i c h is a n offset, d i r e c t l y h e a t e d , f i l a m e n t a r y c a t h o d e w h i c h is us e d to b o m b a r d t h e f l a t c a t h o d e a n d raise i t to e l e c t r o n emlsslx e t e m p e r a t u r e s A m a g n e t i c de vi c e is used to x l b r a t e t h e p o ~ del in t h e p o w d e r m a g a z i n e , w h i c h forms p a r t of t h e ~ a c u u m s y s t e m , t o p r e v e n t c l oggi ng of t h e m a t e r m l a n d i n t e r r u p t i o n of t h e flow I n o r d e r to p r o d u c e e l e c t r o n s a t a h i g h p o s i t i v e p o t e n t i a l r e l a t i v e to t h e a c c e l e r a t i n g e l e c t r o d e of t h e a n a l y s i n g s y s t e m , a c y l i n d r i c a l sleeve of i n s u l a t i n g m a t e r i a l is p l a c e d b e t w e e n t h e ion source a n d t h e t u b e c o n t a i n i n g t h e a c c e l e r a t i n g e l e c t r o d e B o t h t h e t u b e a n d t h e e l e c t rode c a n t h e n be e a r t h e d to p r o v i d e t h e field-free region n e c e s s a r y for t h e flow of t h e ions ~ i t h d r a ~ n a n d a c c e l e r a t e d b y t h e e l e c t r o d e Fhe s u p p o r t s for t h e a n o d e a n d c a t h o d e are w a t e r - c o o l e d a n d a r a d i a t i o n shield is p l a c e d b e t ~ e e n t h e a n o d e a nd the flan ge carr~ lng t h e p o w d e r source, to p r e v e n t o v e r h e a t i n g Somma~re D e s c r i p t i o n d ' u n e source d h o n e m p l o y e e d a n s des s 6 p a r a t e u r s d ' l s o t o p e d a n s l e q u e l l a source de m e t a l d ' o u 1 i s o t o p e choasl d o l t ~tre separ6, est m t r o d m t e d i n s l ' a r c sous forme de p o u d r e
78/IV
(_ M Tulml & U S Atomic Lnergy Comm U 5' Pat 2,079 597
79/IV
J E Mat k & U S Atonm Energy C,mnn U ,~ t'ot 2,6q0 515
0 Proposal of Synchrotron w i t h a Double V a c u u m Chamber I t a l y A s v n c h r o t r o n w i t h a d o u b l e ~ a c u u m c h a m b e r is p r o p o s e d w h i c h could c o m p e t e ~ l t h t h e s t r o n g - f o c u s i n g s y n c h r o t r o n in t h e 1 0 - b e V region The p a r t i c l e s are i n j e c t e d i n t o t h e l a rge x a c u u m c h a m b e r a n d a c c e l e r a t e d to a m o d e r a t e e n e r g y As soon as t h e p a r t i c l e s r e a c h a c e r t a i n e n e r g y t h e b e a m w i l l slide Int o t h e s m a l l e r c h a m b e r w h e r e t h e p a r t i c l e s will be a c c e l e r a t e d up to t h e m a x i m u m fl ux d e n s i t y S e ve ra l p r o b l e m s y e t to be s o l ed are b r l e f l v discussed ( N u c l e a r bc~ence dbslrac/s) Sommaz~e On p r o p o s e un s y n c h r o t r o n a~ec une d o u b l e c h a m b r e a v i d e qul p o u r r a l t e n t r e r en c o m p e t i t i o n ax ec le s y n c h r o t r o n a forte focallsataon d a n s le region de l O - b e V
P e r f o r m a n c e Characteristics of B a r i u m Getters w i t h Particular Reference to Their Application In T h e r m i o m c Valves Ita ly The p e r f o r m a n c e c h a r a c t e r i s t i c s of p u r e b a r i u m g e t t e r d e p o s i t s ( b r i g h t m i r r o r s only) e v a p o r a t e d from a b a r m m - a l u m i n m m a l l o y h a v e b e e n i n v e s t i g a t e d I n t h e I n t r o d u c t i o n a n o u t l i n e is g i v e n of t h e t a s k of t h e g e t t e r In all p h a s e s of t h e p r o d u c t i o n a n d w o r k i n g life of a t h e r m a o m c v a l v e T h e c a p i l l a r y m e t h o d w a s us e d In t he e x p e r i m e n t s b u t w h e r e a s p r e v i o u s w o r k e r s c o n d u c t e d t h i s t e s t w i t h t h e p r e s s u r e in t h e m a n i f o l d b e i n g c o n s t a n t , t h e a u t h o r m o d i f i e d t h e e q u i p m e n t to f a c i l i t a t e a c c u r a t e o p e r a t i o n of t h e t e s t w i t h t h e p r e s s u r e in t h e g e t t e r c h a m b e r c o n s t a n t The r e s u l t s t h u s o b t a i n e d are i n d e p e n d e n t of specific d e s i g n f e a t u r e s of t h e t e s t e m p l o y e d I t is p r o p o s e d to assess g e t t e r p e r f o r m a n c e in t e r m s of ' i n s t a n t a n e o u s a b s o r p t i o n c a p a c i t y ' e x p r e s s e d in h t r e
October, 1954 Vol
Vacuum IV No
8(VIV
Article b~ G Sab ml NUO~.'O etttlei~lt~ i i , Ma~ 1954 555-5%
bl/IV
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VACUUM Classified A b s t r a c t s
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Subsidiary
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i m c r o n p e r second This f a c l h t a t e s in a d d i t i o n t h e c a l c u l a t i o n of t h e t o t a l a b s o r p t i o n c a p a c i t y of t h e g e t t e r b y i n t e g r a t i n g t h e c u r v e g~vmg t h e i n s t a n t a n e o u s a b s o r p t i o n c a p a c i t y v a l u e s o b t a i n e d b y m e a s u r e m e n t If pres e n t e d in t h i s m a n n e r the results of such i n v e s t i g a t i o n s are of i m m e d i a t e a s s i s t a n c e for m d u s t r m l p r a c t i c e s The b e h a v l o u r of t h e g e t t e r s t o w a r d s a n u m b e r of p u r e gases ha s b e e n r e - e x a m i n e d e m p l o y i n g t h e r e v i s e d c a p i l l a r y m e t h o d (See A b s t r a c t 8 1 a / I V ) Sommazre Les c a r a c t e r l s t l q u e s de p e r f o r m a n c e des d e p o t s g e t t e r de b a r y u m pur, (dep6ts b r l l l a n t s s e u l e m e n t ) , e\ ap ores a p a r t l r d ' u n a l h a g e d ' a l u m m l u m et de b a r y u m a l a t e m p e r a t u r e a m b l e n t e , o n t etc e t u d l d e s
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P e r f o r m a n c e Charactenstms of B a r i u m Getters at Elevated W o r k i n g Temperatures of the Valves Italy T h e p e r t o r m a n c e c h a r a c t e r l s t m s of p u r e b a r i u m g e t t e r d e p o s i t s ( b r i g h t m i r r o r s only) e v a p o r a t e d f r o m b a r i u m a l u m i m u m a l l o y s in t h e t e m p e r a t u r e r a n g e of 100M00°C h a v e be e n i n v e s t i g a t e d a n d t h e r e s u l t s are c o m p a r e d w i t h m e a s u r e m e n t s t a k e n a t 20°C (See A b s t r a c t 8 1 / I V ) A rise in t h e o p e r a t i o n a l t e m p e r a t u r e is s h o w n to h a v e a c o n s i d e r a b l e effect on gas a b s o r p t i o n I n t h e h i g h e r t e m p e r a t u r e r e g m n s t h e g e t t e r a b s o r b s g as in q u a n t a t l e s closely a p p r o a c h i n g t h o s e r e q m r e d for t h e f o r m a t i o n of t h e r e s p e c t l x e c h e m i c a l c o m p o u n d s E l e v a t e d t e m p e r a t u r e s a p p e a r to cause t h e m o l e c u l e s of gases, f o r m i n g a n i m p e r m e a b l e l a y e r on t h e g e t t e r a n d t h u s p o i s o n i n g it a t r o o m t e m p e r a t u r e , to diffuse i n t o t h e b o d y of t h e b a r i u m d e p o s i t r e m o v i n g s uc h b a r r i e r l a y e r s e n t i r e l y R e g e n e r a t i o n of e x h a u s t e d m i r r o r d e p o s i t s b y m e a n s of a h e a t t r e a t m e n t h a s be e n s t u d i e d Fhe behax lo ur of b a r i u m m i r r o r s ex a p o r a t e d on glas s surfaces h e a t e d a t 200°C h a s been e x a m i n e d a n d s ome c o m p a r a t i v e s t u d i e s h a x e been m a d e b e t w e e n t h e a b s o r p t i o n c a p a c i t y of f r e s h l y d e p o s i t e d m i r r o r s a f t e r h e a t t r e a t m e n t a n d p r i o r to such t r e a t m e n t The a r t i c l e c o n c l u d e s w i t h o b s e r v a t i o n s on gas e x o l u t l o n from g e t t e r s ",~munuzre L es c a r a c t e r a s t l q u e s de p e r f o r m a n c e des d6pSts g e t t e r de b a r y u m pur, (de pot s b r d l a n f s s e u l e m e n t ) , cx ap ores ~ p a r t J r d ' u n a l h a g e d ' a l u m m m m e t de b a r v u m a des t e m p d r a t u r e s de 100 a 400 'C o n t et6 e t u d l e e s
A p p h c a t m n of a Tracer to Cathode-Gettermg and Gas-Adsorption Problems See A b s t r a c t No 2 1 2 / I
47 --
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PROCESSING
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1954 Vol
Vacuum I V No
81a/IV
A1tl(_l¢ by P della Pott,~ I"ac~tum 4, Oct ](Vt 464-475
82/IV
47
Method for Seahng-off an Evacuated Component Fitted w l t h a Thlck-Walled P u m p i n g S t e m Holland Ex a c u a t e d c o m p o n e n t s such as r a d i o recex~ er v a l v e s f i t t e d w l t h t h i n - w a l l e d p u m p i n g s t e m s p r e s e n t no d i f f i c u l t i e s w i t h r e g a r d to t h e seahng-off of t h e l a t t e r I n t h e case of T V t u b e s ho~xexer t h e p u m p i n g s t e m s are t h i c k - w a l l e d a n d t h e n o r m a l l y e m p l o y e d m a n u a l m e t h o d of sealing-off b y m e a n s of a fl a me u s u a l l y r e s u l t s m r e l e a s i n g a c e r t a i n a m o u n t of gas in t h e final s t a g e s of s e a l i n g t o t h e d e t r i m e n t of t h e r e s i d u a l a t m o s p h e r e in t h e t u b e Also there is a high i n c i d e n c e oi c r a c k s o c c u r r i n g d u r i n g t h i s o p e r a t i o n A n i m p r o v e d m e t h o d of seahng-off t h e p u m p i n g s t e m is d e s c r i b e d ~ h l c h m a k e s t h e w hol e o p e r a t i o n safer A t u b u l a r i n s u l a t i n g comp o n e n t c a r r ) m g a r e s i s t a n c e w i n d i n g on t h e inside is s l i p p e d ove r t h e s t e m a n d p l a c e d in a p o s i t i o n cox e r l n g t h e a r e a w h e r e t h e s t e m is to be sealed off T h e r e s i s t a n c e ~ l n d i n g c a n be c o n n e c t e d t o a s u p p l y an such a m a n n e r t h a t e i t h e r one h a l f or t h e whole of t h e ~ m d m g is h e a t e d I n o r d e r t o effect closure of t h e s t e m an t h e d e s i r e d p l a c e one half on t h e w i n d i n g is c o n n e c t e d to t h e s u p p l y ~ a r m m g up t h e s e c t i on t o be sealed to 380JC for a p e r i o d of six m i n u t e s T h e n t h e l o a d is i n c r e a s e d f r o m 40 W t o 150 W for a pe ri od of a b o u t 25 sec w h m h r e s u l t s in t h e i m m e d i a t e closure of t h e p u m p i n g s t e m A t t h i s j u n c t u r e t h e w hol e of t h e w i n d i n g is i n c o r p o r a t e d na t h e e l e c t r i c a l c i r c u i t a n d t h e load r e d u c e d to 28 W As a result, t h e a r e a a d j a c e n t to t h e p o i n t of closure of t h e s t e m is ~ a r m e d up a n d t h i s f a c i l i t a t e s u n i f o r m and stress-free cooling A f t e r a pe ri od of s i x m i n u t e s t h e h e a t e r e l e m e n t is r e m o v e d a n d t h e s u r p l u s l e n g t h of t h e s t e m c a n be c u t off b y c o n v e n t i o n a l m e a n s Somma¢~e On d o n n e des d e t a i l s sur une n o u v e l l e m e t h o d e p a r l a q u e l l e les q u e u s o t s a p a r m epalsse des t u b e s de r V peux e n t etre scelles sans a u c u n d a n g e r de felure
October,
AI ticle by P della Polta Vacuum 4, ]uly 1954 284-302
~3/IV
W .X Rooxel~ lg V Pt,hps Gloeflampen fabneken German P~ t 889,820
351 4
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Abstract No und Referene~ ~
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I o n Source U m t e d States A n Ion source is d e s c r i b e d to be used for t h e copious p r o d u c t i o n of i ons in an i s ot ope s e p a r a t i n g d e v i c e w h i c h IS s u i t a b l e for p r o d u c i n g i s o t o p e s on a c o m m e r c i a l scale of m a t e r i a l s such as c o p p e r - 6 3 a n d -65, c o b a l t - 5 9 a n d - 6 0 or u r a n i u m -234, -235, -237, - 2 3 8 The source of e l e c t r o n s c ons i s t s of a m a s s i v e t h l m b l e - h k e m a i n c a t h o d e , inside w h i c h is s u p p o r t e d a n a u x l h a r y - c a t h o d e , b o t h m a d e from t u n g s t e n A r o u n d t h e o u t s i d e of t h e m a i n c a t h o d e as p l a c e d a f i l a m e n t w h i c h is h e a t e d t o a t e m p e r a t u r e s u f f i c i e n t l y h i g h to i n i t i a t e e l e c t r o n e m i s s i o n from t h e m a i n c a t h o d e A source of a l t e r n a t i n g ~ o l t a g e IS c o n n e c t e d b e t w e e n t h e m a i n a n d a u x i l i a r y c a t h o d e W h e n e l e c t r o n e m i s s i o n from t h e m a i n c a t h o d e h a s be e n e s t a b l i s h e d t h e a l t e r n a t i n g v o l t a g e e ns ure s t h a t t h e arc d i s c h a r g e b e t w e e n t h e m a i n a n d a u x i l i a r y c a t h o d e IS m a i n t a i n e d , a n d t h e f i l a m e n t is t h e n s ~ l t c h e d off The e x t e r n a l s u p p l y c i r c u i t IS a r r a n g e d so t h a t t h e p o w e r i n p u t to e a c h of t h e e l e c t rode s c a n be c o n t r o l l e d I n d e p e n d e n t l y of t h e o t h e r e l e c t r o d e T h e a n o d e cons i s t s of a p l a t f o r m of t u n g s t e n rods p l a c e d n e a r t o t h e c a t h o d e s t r u c t u r e such t h a t t h e a u x i l i a r y c a t h o d e is s hi e l de d from t h e m a i n d i s c h a r g e b y t h e m a s s i v e e l fe c t of t h e m a i n c a t h o d e M e t a l is fed to t h e arc t h r o u g h a t ube , t h e end of w h i c h is d i r e c t e d t o w a r d s t h e a node p l a t fo rm T h e m e t a l is I n t r o d u c e d in t h e form of a wire or r i b b o n a n d m a y be c o n t m u o u s l 3 or i n t e r m i t t e n t l y fed I o n s p r o d u c e d an t h e m a i n d i s c h a r g e are d i r e c t e d Into t h e ion or i s ot ope s e p a r a t i n g dex ice b v a p p l i c a t i o n of a larg e negatlx e ~ o l t a g e to a c y l i n d r i c a l e l e c t r o d e p l a c e d c o a x i a l l y w i t h t h e arc c a t h o d e , b e t w e e n t h e l a t t e r a n d t h e i s o t o p e s e p a r a t i n g d e v i c e The whole source is m o u n t e d i n a v a c u u m c h a m b e r Somma*re On d o n n e des d 6 t a l l s sur une source d' Ion e m p l o y e e d a n s des a ppa re fl s s c p a r a t e u r s &Isotope, e x e c u t e s p o u r p r o d m r e des i s o t o p e s sur une echelle c o m m e r c l a l e
Method and Apparatus for Producing Ions U m t e d ~lates I s o t o p e s e p a r a t o r s , in w h i c h a b e a m of ions f o r m e d from t he e l e m e n t w hos e i s o t o p e s are to be r e s o l v e d IS b u n c h e d in a c c o r d a n c e w i t h t h e m a s s of t h e i ons p r e s e n t a nd t h e n d e f l e c t e d i n r f fields t o d i r e c t t h e p r e f e r r e d e n r i c h e d g r o u p s of ions i n t o a collector, r e q u i r e ion b e a m s of v e r y h i g h c o n t e n t before a s u b s t a n t i a l ield is o b t a i n e d Also, t h e ion source m u s t be c a p a b l e of c o n t i n u o u s o p e r a t i o n for a c o n s i d e r a b l e F e rl od A v a c u u m arc source, w h i c h fulfils b o t h t h e s e r e q u i r e m e n t s , Is d e s c r i b e d A hol l ow c3 l m d r m a l a n o d e m o u n t e d , w i t h its a x i s v e r t i c a l , a b o v e a flat i n d i r e c t l y h e a t e d a n o d e h a v i n g a c e n t r a l hole, is, in t u r n , s e t b e l o ~ a de~ ice for d r o p p i n g a s t e a d y s t r e a m of p o w d e r e d m a t e r i a l a x i a l l y t h r o u g h t h e a s s e m b l y Thi s p o w d e r is x apormed b y t h e r a d i a n t h e a t from t h e a n o d e a n d t h e gas is l o m s e d in t h e a rc A n y p o w d e r r e m a i n i n g falls t h r o u g h t he hole in t h e c a t h o d e , below w h i c h is a n offset, d i r e c t l y h e a t e d , f i l a m e n t a r y c a t h o d e w h i c h is us e d to b o m b a r d t h e f l a t c a t h o d e a n d raise i t to e l e c t r o n emlsslx e t e m p e r a t u r e s A m a g n e t i c de vi c e is used to x l b r a t e t h e p o ~ del in t h e p o w d e r m a g a z i n e , w h i c h forms p a r t of t h e ~ a c u u m s y s t e m , t o p r e v e n t c l oggi ng of t h e m a t e r m l a n d i n t e r r u p t i o n of t h e flow I n o r d e r to p r o d u c e e l e c t r o n s a t a h i g h p o s i t i v e p o t e n t i a l r e l a t i v e to t h e a c c e l e r a t i n g e l e c t r o d e of t h e a n a l y s i n g s y s t e m , a c y l i n d r i c a l sleeve of i n s u l a t i n g m a t e r i a l is p l a c e d b e t w e e n t h e ion source a n d t h e t u b e c o n t a i n i n g t h e a c c e l e r a t i n g e l e c t r o d e B o t h t h e t u b e a n d t h e e l e c t rode c a n t h e n be e a r t h e d to p r o v i d e t h e field-free region n e c e s s a r y for t h e flow of t h e ions ~ i t h d r a ~ n a n d a c c e l e r a t e d b y t h e e l e c t r o d e Fhe s u p p o r t s for t h e a n o d e a n d c a t h o d e are w a t e r - c o o l e d a n d a r a d i a t i o n shield is p l a c e d b e t ~ e e n t h e a n o d e a nd the flan ge carr~ lng t h e p o w d e r source, to p r e v e n t o v e r h e a t i n g Somma~re D e s c r i p t i o n d ' u n e source d h o n e m p l o y e e d a n s des s 6 p a r a t e u r s d ' l s o t o p e d a n s l e q u e l l a source de m e t a l d ' o u 1 i s o t o p e choasl d o l t ~tre separ6, est m t r o d m t e d i n s l ' a r c sous forme de p o u d r e
78/IV
(_ M Tulml & U S Atomic Lnergy Comm U 5' Pat 2,079 597
79/IV
J E Mat k & U S Atonm Energy C,mnn U ,~ t'ot 2,6q0 515
0 Proposal of Synchrotron w i t h a Double V a c u u m Chamber I t a l y A s v n c h r o t r o n w i t h a d o u b l e ~ a c u u m c h a m b e r is p r o p o s e d w h i c h could c o m p e t e ~ l t h t h e s t r o n g - f o c u s i n g s y n c h r o t r o n in t h e 1 0 - b e V region The p a r t i c l e s are i n j e c t e d i n t o t h e l a rge x a c u u m c h a m b e r a n d a c c e l e r a t e d to a m o d e r a t e e n e r g y As soon as t h e p a r t i c l e s r e a c h a c e r t a i n e n e r g y t h e b e a m w i l l slide Int o t h e s m a l l e r c h a m b e r w h e r e t h e p a r t i c l e s will be a c c e l e r a t e d up to t h e m a x i m u m fl ux d e n s i t y S e ve ra l p r o b l e m s y e t to be s o l ed are b r l e f l v discussed ( N u c l e a r bc~ence dbslrac/s) Sommaz~e On p r o p o s e un s y n c h r o t r o n a~ec une d o u b l e c h a m b r e a v i d e qul p o u r r a l t e n t r e r en c o m p e t i t i o n ax ec le s y n c h r o t r o n a forte focallsataon d a n s le region de l O - b e V
P e r f o r m a n c e Characteristics of B a r i u m Getters w i t h Particular Reference to Their Application In T h e r m i o m c Valves Ita ly The p e r f o r m a n c e c h a r a c t e r i s t i c s of p u r e b a r i u m g e t t e r d e p o s i t s ( b r i g h t m i r r o r s only) e v a p o r a t e d from a b a r m m - a l u m i n m m a l l o y h a v e b e e n i n v e s t i g a t e d I n t h e I n t r o d u c t i o n a n o u t l i n e is g i v e n of t h e t a s k of t h e g e t t e r In all p h a s e s of t h e p r o d u c t i o n a n d w o r k i n g life of a t h e r m a o m c v a l v e T h e c a p i l l a r y m e t h o d w a s us e d In t he e x p e r i m e n t s b u t w h e r e a s p r e v i o u s w o r k e r s c o n d u c t e d t h i s t e s t w i t h t h e p r e s s u r e in t h e m a n i f o l d b e i n g c o n s t a n t , t h e a u t h o r m o d i f i e d t h e e q u i p m e n t to f a c i l i t a t e a c c u r a t e o p e r a t i o n of t h e t e s t w i t h t h e p r e s s u r e in t h e g e t t e r c h a m b e r c o n s t a n t The r e s u l t s t h u s o b t a i n e d are i n d e p e n d e n t of specific d e s i g n f e a t u r e s of t h e t e s t e m p l o y e d I t is p r o p o s e d to assess g e t t e r p e r f o r m a n c e in t e r m s of ' i n s t a n t a n e o u s a b s o r p t i o n c a p a c i t y ' e x p r e s s e d in h t r e
October, 1954 Vol
Vacuum IV No
8(VIV
Article b~ G Sab ml NUO~.'O etttlei~lt~ i i , Ma~ 1954 555-5%
bl/IV
550 4
VACUUM Classified A b s t r a c t s
IV - -
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Subsidiary
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i m c r o n p e r second This f a c l h t a t e s in a d d i t i o n t h e c a l c u l a t i o n of t h e t o t a l a b s o r p t i o n c a p a c i t y of t h e g e t t e r b y i n t e g r a t i n g t h e c u r v e g~vmg t h e i n s t a n t a n e o u s a b s o r p t i o n c a p a c i t y v a l u e s o b t a i n e d b y m e a s u r e m e n t If pres e n t e d in t h i s m a n n e r the results of such i n v e s t i g a t i o n s are of i m m e d i a t e a s s i s t a n c e for m d u s t r m l p r a c t i c e s The b e h a v l o u r of t h e g e t t e r s t o w a r d s a n u m b e r of p u r e gases ha s b e e n r e - e x a m i n e d e m p l o y i n g t h e r e v i s e d c a p i l l a r y m e t h o d (See A b s t r a c t 8 1 a / I V ) Sommazre Les c a r a c t e r l s t l q u e s de p e r f o r m a n c e des d e p o t s g e t t e r de b a r y u m pur, (dep6ts b r l l l a n t s s e u l e m e n t ) , e\ ap ores a p a r t l r d ' u n a l h a g e d ' a l u m m l u m et de b a r y u m a l a t e m p e r a t u r e a m b l e n t e , o n t etc e t u d l d e s
O
P e r f o r m a n c e Charactenstms of B a r i u m Getters at Elevated W o r k i n g Temperatures of the Valves Italy T h e p e r t o r m a n c e c h a r a c t e r l s t m s of p u r e b a r i u m g e t t e r d e p o s i t s ( b r i g h t m i r r o r s only) e v a p o r a t e d f r o m b a r i u m a l u m i m u m a l l o y s in t h e t e m p e r a t u r e r a n g e of 100M00°C h a v e be e n i n v e s t i g a t e d a n d t h e r e s u l t s are c o m p a r e d w i t h m e a s u r e m e n t s t a k e n a t 20°C (See A b s t r a c t 8 1 / I V ) A rise in t h e o p e r a t i o n a l t e m p e r a t u r e is s h o w n to h a v e a c o n s i d e r a b l e effect on gas a b s o r p t i o n I n t h e h i g h e r t e m p e r a t u r e r e g m n s t h e g e t t e r a b s o r b s g as in q u a n t a t l e s closely a p p r o a c h i n g t h o s e r e q m r e d for t h e f o r m a t i o n of t h e r e s p e c t l x e c h e m i c a l c o m p o u n d s E l e v a t e d t e m p e r a t u r e s a p p e a r to cause t h e m o l e c u l e s of gases, f o r m i n g a n i m p e r m e a b l e l a y e r on t h e g e t t e r a n d t h u s p o i s o n i n g it a t r o o m t e m p e r a t u r e , to diffuse i n t o t h e b o d y of t h e b a r i u m d e p o s i t r e m o v i n g s uc h b a r r i e r l a y e r s e n t i r e l y R e g e n e r a t i o n of e x h a u s t e d m i r r o r d e p o s i t s b y m e a n s of a h e a t t r e a t m e n t h a s be e n s t u d i e d Fhe behax lo ur of b a r i u m m i r r o r s ex a p o r a t e d on glas s surfaces h e a t e d a t 200°C h a s been e x a m i n e d a n d s ome c o m p a r a t i v e s t u d i e s h a x e been m a d e b e t w e e n t h e a b s o r p t i o n c a p a c i t y of f r e s h l y d e p o s i t e d m i r r o r s a f t e r h e a t t r e a t m e n t a n d p r i o r to such t r e a t m e n t The a r t i c l e c o n c l u d e s w i t h o b s e r v a t i o n s on gas e x o l u t l o n from g e t t e r s ",~munuzre L es c a r a c t e r a s t l q u e s de p e r f o r m a n c e des d6pSts g e t t e r de b a r y u m pur, (de pot s b r d l a n f s s e u l e m e n t ) , cx ap ores ~ p a r t J r d ' u n a l h a g e d ' a l u m m m m e t de b a r v u m a des t e m p d r a t u r e s de 100 a 400 'C o n t et6 e t u d l e e s
A p p h c a t m n of a Tracer to Cathode-Gettermg and Gas-Adsorption Problems See A b s t r a c t No 2 1 2 / I
47 --
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PROCESSING
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1954 Vol
Vacuum I V No
81a/IV
A1tl(_l¢ by P della Pott,~ I"ac~tum 4, Oct ](Vt 464-475
82/IV
47
Method for Seahng-off an Evacuated Component Fitted w l t h a Thlck-Walled P u m p i n g S t e m Holland Ex a c u a t e d c o m p o n e n t s such as r a d i o recex~ er v a l v e s f i t t e d w l t h t h i n - w a l l e d p u m p i n g s t e m s p r e s e n t no d i f f i c u l t i e s w i t h r e g a r d to t h e seahng-off of t h e l a t t e r I n t h e case of T V t u b e s ho~xexer t h e p u m p i n g s t e m s are t h i c k - w a l l e d a n d t h e n o r m a l l y e m p l o y e d m a n u a l m e t h o d of sealing-off b y m e a n s of a fl a me u s u a l l y r e s u l t s m r e l e a s i n g a c e r t a i n a m o u n t of gas in t h e final s t a g e s of s e a l i n g t o t h e d e t r i m e n t of t h e r e s i d u a l a t m o s p h e r e in t h e t u b e Also there is a high i n c i d e n c e oi c r a c k s o c c u r r i n g d u r i n g t h i s o p e r a t i o n A n i m p r o v e d m e t h o d of seahng-off t h e p u m p i n g s t e m is d e s c r i b e d ~ h l c h m a k e s t h e w hol e o p e r a t i o n safer A t u b u l a r i n s u l a t i n g comp o n e n t c a r r ) m g a r e s i s t a n c e w i n d i n g on t h e inside is s l i p p e d ove r t h e s t e m a n d p l a c e d in a p o s i t i o n cox e r l n g t h e a r e a w h e r e t h e s t e m is to be sealed off T h e r e s i s t a n c e ~ l n d i n g c a n be c o n n e c t e d t o a s u p p l y an such a m a n n e r t h a t e i t h e r one h a l f or t h e whole of t h e ~ m d m g is h e a t e d I n o r d e r t o effect closure of t h e s t e m an t h e d e s i r e d p l a c e one half on t h e w i n d i n g is c o n n e c t e d to t h e s u p p l y ~ a r m m g up t h e s e c t i on t o be sealed to 380JC for a p e r i o d of six m i n u t e s T h e n t h e l o a d is i n c r e a s e d f r o m 40 W t o 150 W for a pe ri od of a b o u t 25 sec w h m h r e s u l t s in t h e i m m e d i a t e closure of t h e p u m p i n g s t e m A t t h i s j u n c t u r e t h e w hol e of t h e w i n d i n g is i n c o r p o r a t e d na t h e e l e c t r i c a l c i r c u i t a n d t h e load r e d u c e d to 28 W As a result, t h e a r e a a d j a c e n t to t h e p o i n t of closure of t h e s t e m is ~ a r m e d up a n d t h i s f a c i l i t a t e s u n i f o r m and stress-free cooling A f t e r a pe ri od of s i x m i n u t e s t h e h e a t e r e l e m e n t is r e m o v e d a n d t h e s u r p l u s l e n g t h of t h e s t e m c a n be c u t off b y c o n v e n t i o n a l m e a n s Somma¢~e On d o n n e des d e t a i l s sur une n o u v e l l e m e t h o d e p a r l a q u e l l e les q u e u s o t s a p a r m epalsse des t u b e s de r V peux e n t etre scelles sans a u c u n d a n g e r de felure
October,
AI ticle by P della Polta Vacuum 4, ]uly 1954 284-302
~3/IV
W .X Rooxel~ lg V Pt,hps Gloeflampen fabneken German P~ t 889,820
351 4