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SATURNE LATEST RESULTS FOR POLARIZED BEAMS
P. Chamouard, J. Lagniel, J. Lemaire, A. Tkatchenko, J. Yonnet
To cite this version:
P. Chamouard, J. Lagniel, J. Lemaire, A. Tkatchenko, J. Yonnet. SATURNE LATEST RESULTS FOR POLARIZED BEAMS. Journal de Physique Colloques, 1990, 51 (C6), pp.C6-569-C6-572.
�10.1051/jphyscol:1990675�. �jpa-00230945�
P.A. CHAMOUARD, J.M. LAGNIEL,
J . L . LEMAIRE,A. TKATCHENKO and J. YONNET
Laboratoire National SATURNE, CEA-DSM et CNRS-
I N Z P ~ ,Saclay, F-91191 Gif sur Yvette, France
R6sum6
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Les i n t e n s i t e s e n p r o t o n s e t e n deutons o n t pu e t r e progressivement p o r t 6 e sB
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2 . 1 0 ~ ~ p a r t i c u l e s / c y c l e d e p u i s l a mise en s e r v i c e d e MIMAS en 1987 e t g r a c e aux a d l i o r a t i o n s f a i t e s s u r l a s o u r c e . I1 n'y a pas d e r6sonance d e d d p o l a r i s a t i o n e n d e u t o n s . Les rksonances d e d e p o l a r i s a t i o n e n p r o t o n s dans MIMAS e t SATURNE o n t f a i t l ' o b j e t d 1 6 t u d e s s yst6matiques j u s q u ' a 1 1 6 n e r g i e maximale d e SATURNE (2.91 GeV).Compte t e n u des a m e l i o r a t i o n s e n c o r e p o s s i b l e s s u r l a f f u r c e e t moyennant une i n j e c t i o n d n e r g i e p l u s d l e v e e dans MIMAS une i n t e n s i t d de 5.10 p ou d p a r c y c l e e s t p o s s i b l e . A b s t r a c t
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The i n t e n s i t i e s f o r p o l a r i z e d p r o t o n s o r d e u t e r o n s have been reached up t o 2.10 11 p o r d by c y c l e s i n c e MIMAS o p e r a t i o n i n 1987 and a l s o w i t h t h e l a s t improvements of t h e s o u r c e . There is no d e p o l a r i z a t i o n f o r d e u t e r o n s b u t f o r p r o t o n s a l l t h e d e p o l a r i z a t i o n s i n MIMAS and SATURNE have been s t u d i e d up t o t h e maximum energy. With t h e p o s s i b l e improvements ontPf
s o u r c e , a s s o c i a t e d t o a n h i g h e r i n j e c t i o n energy i n t o MIMAS, i n t e n s i t i e s up t o 5.10 p o r d a r e p o s s i b l e .1
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ImRoDUCTIONThe SATURNE I1 complex f o r p o l a r i z e d beams i s c o n s t i t u t e d b y a 400 kV DC p r e i n j e c t o r h o u s i n g t h e p o l a r i z e d s o u r c e . The b o o s t e r - s t o r a g e r i n g MIMAS and r i n g SATURNE 11. One p o l a r i m e t e r i s s e t a f t e r t h e p r e i n j e c t o r and d e d i c a t e d t o t h e p o l a r i z a t i o n c o n t r o l of d e u t e r o n s . The o t h e r p o l a r i m e t e r i s placed a f t e r t h e f i r s t SATURNE1s e x t r a c t i o n channel.
SATURNE NATIONAL LABORATORY
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1990675
C6-570 COLLOQUE DE PHYSIQUE
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THE POLARIZED SOURCE "HYPERION"This s o u r c e b u i l t i n 1981 began t o o p e r a t e i n 1982. The high v o l t a g e t e r m i n a l houses :
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a ) t h e ground s t a t e atomic s o u r c e : RF d i s s o c i a t o r f = 17 MHz, t h e t a p e r e d s e x t u p o l e and removable RF t r a n s i t i o n s ( 2 f o r p r o t o n s , 3 f o r d e u t e r o n s ) , t h e n o z z l e made of gold covered copper i s cooled a t 80K. The atomic s o u r c e o p e r a t e s i n t h e p u l s e d mode (both t h e p r e s s u r e and m ) ,-
b) t h e e l e c t r o n beam r e f l e x i o n i z e r b u i l t by ANAC has been deeply modified mainly on t h e f o l l o w i n g p o i n t s :-
a v e r y f i n e alignment between t h e mechanical a x i s of t h e e l e c t r o s t a t i c e l e c t r o d e s and t h e magnetic a x i s of c o i l s ,-
a r e l i a b l e e l e c t r o n gun equipped w i t h alumina i n s u l a t o r s , tantalum and molybdenum e l e c t r o d e s allowing t o o p e r a t e a t high temperatures without alignment l o s s e s ,-
t h e v01 tage of t h e e l e c t r o n e x t r a c t i o n e l e c t r o d e i s pulsed, i n t h e s e c o n d i t i o n s i t is p o s s i b l e t o o p e r a t e with higher e l e c t r o n c u r r e n t . The DC mode i s only used d u r i n g o u t g a s s i n g .-
c ) t h e beam i s e x t r a c t e d a t 17 keV, a f t e r i o n i z a t i o n t h e p o l a r i z a t i o n is s e t i n t h e v e r t i c a l d i r e c t i o n by means of a n e l e c t r o s t a t i c m i r r o r followed by a solenoyd. Then t h e beam i s a c c e l e r a t e d up t o 400 keV. The s t a n d a r d beam o p e r a t i o n i s :-
e x t r a c t e d c u r r e n t a t 17 keV : 400-
500 pA-
p u l s e l e n g t h 1.5 msec ( p r o t o n s ) 1 msec ( d e u t e r o n s ) 3 . 1 0 - ~ mrad (80%)The c u r r e n t a t MIMAS's i n f l e c t o r i s 200-250 ,A g i v i n g 2.1011 p o r d a c c e l e r a t e d i n MIMAS and SATURNE
.
3
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e T S OF POLARIZATIONI m n e d i a t e l y w i t h MIMAS, a f a c t o r of t e n has been g o t t e n on t h e i n t e n s i I f r , i t has been n e c e s s a r y t o modify t h e high energy p o l a r i m e t e r t o be a b l e t o r e c e i v e 2.10 p a r t i c l e s . Nevertheless a new p o l a r i m e t e r has been designed and w i l l be s e t i n next january ( l ) . Deuterons beams : No d e p o l a r i z i n g resonance has been observed i n MIMAS and
SATURNE, and t y p i c a l l y t h e p o l a r i z a t i o n of t h e beam i s 85 % of :
Pz =
$
213 Pzz =2
i n t e n s i t y 2.1011 d Pz =-
1 / 3 Pzz =-
lThe energy range of MIMAS i s from 400 keV t o 47 MeV, t h e beam i s n o t r e l a t i v i s t i c V = 1 ; t h a t means i f t h e o p e r a t i n g p o i n t i s c l o s e l f o a r e s o n a n t l i n e , t h e beam w i l l remain a l o n g time on t h e l i n e ; t h e high i n t e n s i t y (2.10 p ) induces by space charge e f f e c t a v a r i a t i o n of wave numbers (vz = 2.2) Auz= 0.1. ; To day, MIMAS i s t h e o n l y machine space charge dominated with p o l a r i z e d beams.
The l i n e YGp 4
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vz (vz = 2.206) i s s e t on t h e i n j e c t i o n p o i n t , t h e a s s o c i a t i o n of t h e space charge e f f e c t and synchrotron o s c i l l a t i o n during t h e a d i a b a t i c c a p t u r e and t h e beginning of a c c e l e r a t i o n produces m u l t i p l e c r o s s i n g s of t h e l i n e , even i f t h i s l i n e i s weak, t h e p o l a r i z a t i o n f a l l s down t o 65 % ( i n s t e a d of 90 %), t h e c o r r e c t i o n of t h i s l i n e by c o r r e c t i o n quadrupoles gives o n l y an improvement of 10 %. I n t h e s e c o n d i t i o n s t h e v e r t i c a l o p e r a t i n g p o i n t has been modified : vz = 2.48 c l o s e t o t h e h a l f i n t e g e r allowing a l a r g e p o s s i t l e Avz w i t h o u t c r o s s i n g Y G ; 4-
vz i n t h e s e c o n d i t i o n a p o l a r i z a t i o n of 90 % w i t h 2.10 is p o s s i b l e ( a l l measurements f o r MIMAS t u n i n g have been made a t 250 MeV i n SATURNE, s e e diagram)4
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SATURNE TUNINGI n SATURNE d ~ / d t a l l o w s , t h e p o s s i b i l i t y t o change t h e speed of c r o s s i n g t h e l i n e s , and t h e c o r r e c t i o n a r e made by 3 ways ( 2 ) :
vz v a r i a t i o n mu1 t i - p u l s e d d i p o l e s c o r r e c t i o n multi-pulsed mu1 t i p l e s c o r r e c t i o n s
The l i n e YG = 2 i s c o r r e c t e d ( d i p o l e s c o r r e c t i o n s )
YG 3 , 4, 5 , 6, 7 a r e f l i p p e d ( t h e f l i p i s enhanced by d i p o l e c o r r e c t o r s f o r 3 and 4).
The l i n e VG = vz and PG = 8
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vz a r e f l i p p e d w i t h vz v a r i a t i o n . The l i n e sYG = N
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M vz a r e crossed w i t h quadrupolar c o r r e c t i o n s and vz v a r i a t i o n , each one h a s an e f f e c t .The l i n e YG = vx i s c o r r e c t e d by 4 skew quadrupoles.
A v e r y f l e x i b l e c a n p u t e r c o n t r o l (hard and s o f t ) f o r t h e c o r r e c t o r s and main quadrupoles i s n e c e s s a r y .
Other l i n e s VG = N
+
vx vz c a n be e x c i t e d d u r i n g e x t r a c t i o n by t h e main hexapoles inducing t h e b e t a t r o n resonance ux = 1113.The l i n e s a r e avoided by v e r t i c a l t u n i n g vz.
C6-572
COLLOQUE DE PHYSIQUEA p r e d i c t i v e computer p r o g r a m gives a l l t h e p o s s i b l e l i n e s up t o t h e t h i r d o r d e r , t o a s s m e t h e b e s t p o s s i b l e t u n i n g of t h e machine when an energy i s needed by t h e u s e r , t h i s programm shows t h e l i n e s i n t h e u x , uz diagram f o r a given energy but a l s o t h e p o s i t i o n of t h e l i n e s i n t h e diagram u x , 1.2 versus W. To day, t h e p o l a r i z a t i o n of t h e protons beam i s 80 X up t o 2.91 GeV (maximum 2.95 GeV) w i t h 2.10 11 p.
POSSIBLE IMPROVEMENTS
A t e s t bench has been s e t i n o r d e r t o s t u d y t h e c o o l i n g of t h e atomic beam i n t h e n o z z l e , t h e l a s t r e s u l t s have shown t h e p o s s i b i l i t y t o reduce t h e temperature a t 35K w i t h N2 i n j e c t i o n i n t h e n o z z l e , i s t h e s e c o n d i t i o n s w i t h a new s e x t u p o l e a n improvement of 1.7 i s p o s s i b l e ( 3 ) .
Using h i g h e r v o l t a g e s on t h e i o n i z e r a l l o w i n g l a r g e r e l e c t r o n d e n s i t y t h e e x t r a c t e d c u r r e n t h a s been reached t o 700 p A ; i n t h e s e c o n d i t i o n t h e t o t a l improvement on t h e i o n beam i n t e n s i t y i s :
700/500 X 1 , 7 = 2.38
corresponding to 1.2 mA e x t r a c t e d of t h e i o n i s e r . I f t h e beam i s i n j e c t e d a t 800 kfY allowing t h e s a n e space charge a n dynamic e f f e c t s on t h e beam, a n i n t e n s i t y of 5.10 w i l l be p o s s i b l e .
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CONCLUSIONTo day, SATURNE's p o l a r i z e d beams r e s u l t s show :
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t h e p o s s i b i l i t y t o g e t high i n t e n s i t i e s , probably 1012 p o r d by c y c l e w i t h reasonable improvements on t h e s o u r c e ,-
t h e p o l a r i z a t i o n can be conserved a t l a r g e v a l u e s (80%) w i t h a minimm of l o s s e s even w i t h many d e p o l a r i z i n g l i n e s .REFERENCES
/ l / Chanouard, PA., Rommel, G . , O l i v i e r , M . , . . . . Tkatchenko, A., Mimas Commissioning EPAC, . . Rome, 1988
/ 2 / ~ a c l a r r ~ ~ .
,
A c c e l e r a t i o n de protons p o l a r i s e s , Journees d'Etudes S a t u r n e 2, Auxois, 1977.
/3/ = i r e ,
