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SUPERCONDUCTING SOLENOIDS FOR NUCLEAR PHYSICS AT ORSAY
G. Levy, S. Buhler, M. Kovalski, A. Liebe
To cite this version:
G. Levy, S. Buhler, M. Kovalski, A. Liebe. SUPERCONDUCTING SOLENOIDS FOR NU- CLEAR PHYSICS AT ORSAY. Journal de Physique Colloques, 1984, 45 (C1), pp.C1-821-C1-826.
�10.1051/jphyscol:19841168�. �jpa-00223642�
JOURNAL
DEPHYSIQUE
Colloque C1, suppl6rnent a u no 1, Tome 45, janvier 1984 page C1-821
SUPERCONDUCTING SOLENOIDS FOR NUCLEAR P H Y S I C S AT ORSAY G. Levy, S. Buhler, M. Kovalski and A. L i e b e
I n s t i t u t de Physique IVucZ6a$re, B.P. N o 2, 91406 Orsay, France
Resume
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Deux systemes u t i l i s a n t de grands solenoides supraconducteurs sont m s . Le premier, SOLENO, e s t compose de deux aimant's (3T, 600 KJ chacun)e t remplacera un t r i p l e t de l e n t i l l e s magnetiques. Pour l e moment un seul aimant e s t en fonctionnement. Le deuxieme systeme, CRYEBIS 11, avec un s o l e - noide f o u r n i s s a n t 5T, e s t c o n s t r u i t en double exemplaire pour deux sources d ' i o n s l o u r d s : une pour n o t r e l a b o r a t o i r e e t l ' a u t r e pour I'INSTITUT DE PHYSIQUE ATOMIQUE/STOCKHOLM (Suede). Ce systeme u t i l i s e un i n t e r r u p t e u r supra- conducteur pour c o u r t - c i r c u i t e r l e courant s u r l ' a i m a n t .
Abstract
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Two systems using l a r g e superconducting solenoids are described.The f i r s t , SOLENO, i s composed o f two magnets (3T, 600 KJ each) and w i l l replace a standard t r i p l e t o f magnetic lenses ; f o r t h e moment o n l y t h e f i r s t magnet has gone i n t o operation. The second system, a 5T solenoid, CRYEBIS 11, i s b u i l t i n d u p l i c a t e and w i l l be used on heavy i o n sources : one f o r o u r l a b o r a t o r y and t h e o t h e r o n e f o r t h e RESEARCH INSTITUTE OF PHYSICS/STOCKHOLM (Sweden). This system employs a superconducting switch t o s h o r t - c i c u i t t h e c u r r e n t on the magnet.
INTRODUCTION
For our l a b o r a t o r y , t h e f i r s t approach t o s u p e r c o n d u c t i v i t y was design and construc- t i o n , i n a j o i n t c o l l a b o r a t i o n between CEN/SACLAY and IPN/ORSAY, o f a l a r g e super- conducting solenoid SUPER SOLO, an e s s e n t i a l component o f a heavy i o n source CRYEBIS
I
/I/ f o r the synchrotron SATURNE I 1 a t SACLAY.The SOLENO p r o j e c t was born i n 1979 / 2 / when t h e p h y s i c i s t s wanted t o r e p l a c e a standard t r i p l e t of focussing magnets w i t h a device o f improved performance (azimu- t h a l symmetry, l a r g e s o l i d angle, good magnetic r i g i d i t y ) which proved t o be super- conductive.
S h o r t l y a f t e r , o u r l a b o r a t o r y s t a r t e d t h e CRYEBIS I1 p r o j e c t / 3 / f o r atomic and nuclear physics research, a system r o u g h l y s i m i l a r t o CRYEBIS I, where as t h e super- conducting s o l e n o i d produces now 5T compared t o 3T f o r CRYEBIS 1. I n a c o n t r a c t w i t h the RESEARCH INSTITUTE OF PHYSICS/STOCKHOLM, a d u p l i c a t e i s now b u i l t f o r t h i s i n s - t i t u t e .
The design and t h e winding o f these magnets has been accomplished w i t h t h e precious a i d o f CEN/SACLAY.
The SOLENO SPECTROMETER ( F i g . 1) i s composed o f 2 same superconducting magnets and intended f o r d e t e c t i o n o f charged p a r t i c l e s around zero degrees. The main characte- r i s t i c s a r e :
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19841168
C1-822 JOURNAL DE PHYSIQUE
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a l a r g e s o l i d angle (100 msr)-
an azimuthal symmetry around t h e beam a x i s-
a good acceptance o f p a r t i c l e s w i t h l a r g e r i g i d i t y (0.81 T xm)
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a low g e o m e t r i c a l a b e r r a t i o n-
t h e magnetic s h i e l d a l l o w s t h e o b j e c t and image zone f r e e .-
t h e system i s c o m p a t i b l e w i t h t h e a c c e l e r a t o r s o f IPN/ORSAY, GRENOBLE and GANIL-
t h e second c o i l w i l l extend t h e e x p e r i m e n t a l c a p a b i l i t i e s (Time o f f l i g h t experiments).1
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Magnet C h a r a c t e r i s t i c s ( f o r 1 c o i l ) C o i l i n s i d e d i a m e t e r 0.486 m C o i l o u t s i d e d i a m e t e r 0.52 mC o i l l e n g t h 0.75 m
Number o f 1 ayers 12 l a y e r s T o t a l number o f t u r n s 5902 t u r n s
S t a i n l e s s s t e e l hoop's s t r e s s 1 l a y e r w i t h r e c t a n g u l a r w i r e 2 x 4 mm O p e r a t i o n a l c u r r e n t 375 A
C e n t r a l f i e l d 3.10 T
Inductance 8.75 H
S t o r e d energy 600 KJ
Weight o f w i r e 100 daN
T o t a l l e n g t h 9300 m
The w i n d i n g i s vacuum-grease impregnated. The s t a i n l e s s - s t e e l mandrel serves a l s o as an i n t e r n a l h e l i u m w a l l .
2
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Wire C h a r a c t e r i s t i c s S u p p l i e rDimensions b a r e
Dimensions i n s u l a t e d ( formvar ) Copper/Sc r a t i o
Sc f i l a m e n t s : d i a m e t e r number t w i s t p i t c h Superconductor
C r i t i c a l c u r r e n t a t 4.2 K and 5T MC A
1. x 1.43 mm 1.1 x 1.53 mm 2/1 47 microns 276 25 mm
Niobium 46.5 p c - 800 A
T i t a n i u m
3
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C o i l p r o t e c t i o n ( F i g . 2)T h r e s h o l d o f t h e quench d e t e c t o r : 0.2 V and 0.05 s C u r r e n t Breaker d e l a y t i m e : 0.15 s
Maximum t e m p e r a t u r e r i s e : 100°K
Only 15% o f t h e t o t a l energy i s dumped i n t o t h e p r o t e c t i o n r e s i s t a n c e
SOLENO
ST&BIISLOS 1 6 '
PROTECTIOURESISTAW -7
4
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C r y o s t a t - c r y o g e n i c s ( F i g . 3 )F i g .
X .DUSTABLE "&LYE
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ELEORO VAL=T#
D . % m m VAL".W--- SECURITY VALVE
g d q b
SELECTOR-+ RESrRlCTlON
@ PREssue~ G ~ ~ G E (~cOIFFERENTI~LI THCR105TliT
.ILLOW METER L LH- L N E L MEASUREMENT
HE&TER
CRYOSTAT WITH SOLENOID RADIATION SHIELD CURRENT LFADS RESTRICTION
DISCHARGE VALVE ( 3 0 MBAR) DISCHARGE VALVE (50 MBAR) SECURITY VALVE (0.5 BAR) 30°C WATER BATH
FLOW METER GAS COUNTER
Cl-824 JOURNAL
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PHYSIQUEThe main dimensions o f t h e vacuum t a n k a r e a warm a p e r t u r e o f 0.36 m, an e x t e r n a l diameter o f 0.85 m and a t o t a l l e n g t h o f 0.984 m.
According t o t h e design, t h e c o i l c e n t r e i s s h i f t e d o f 15 mm w i t h r e g a r d t o t h e c e n t r e o f e x t e r n a l magnetic s h i e l d , which i s s p l i t t e d i n o r d e r t o conserve t h e a z i - muthal symmetry. When t h e c o i l i s e n e r g i z e d , t h i s s h i f t i n v o l v e s i m p o r t a n t magnetic a x i a l f o r c e s which a t t a i n under c e r t a i n c o n d i t i o n s 17,000 daN. So, t h e c o i l t a n k i s chocked b y 3 f i b e r g l a s s r e i n f o r c e d epoxy t h r u s t - b l o c k s on each s i d e . Each t h r u s t b l o c k accepts a 6,000 daN compressive s t r e n g t h .
The c u r r e n t l e a d s consists o f a bundle o f 35 t w i s t e r copper b r a i d s (0.127 x 1.6 x 570 mm) f i t t e d i n t o a s t a i n l e s s s t e e l t u b e ($. = 9 mm). The o p t i m a l w o r k i n g p o i n t i s o b t a i n e d between 300 and 350 A w i t h h e a t l o s s J s about 2.1 mW/A. The h e l i u m gaz f l o w t h r o u g h each l e a d i s about 0.5 m3/h w i t h generates a pressure drop about 0.3 KPa ( 3 mbar).
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T e s t i n g and O p e r a t i o nCool down : i n i t i a l c o o l down d e l a y w i t h LN2 : 8 hours c o o l down and f i l l up w i t h LHe : 5 hours Consumption : 40 R o f LN2 and 150 R o f LHe
Normal r u n n i n g : The t o t a l consumption o f LHe i n c l u d i n g t r a n s f e r s i s about SR/hours.
The magnetic measurements had shown t h a t t h e f i e l d q u a l i t y c l o s e d t o e x p e c t a t i o n s . Displacement o f t h e magnetic a x i s towards t h e geometric a x i s under o p e r a t i o n n a l con- d i t i o n s i s p o s s i b l e through an adjustment o f t h e suspension r o d s and c o n t r o l l e d w i t h a X-Y semiconductor d e t e c t o r .
CRYEBIS I 1
CRYEBIS I 1 ( F i g . 4) w i l l be used as a t e s t i n g bench f o r a c c e l e r a t o r s i o n source and as a source f o r atomic p h y s i c s experiments. The goal o f t h e p r o j e c t i s t o o b t a i n f u l l y s t r i p p e r i o n s f r o m 1 8 + ~ r t o 5 4 + ~ e . I t w i l l be w o r k i n g i n s u l a t e d f r o m t h e ground (50 KV) and w i t h a f i x e d magnetic f i e l d , which authorizes t h e use o f a super- c o n d u c t i n g s w i t c h t o t r a p t h e c u r r e n t a l l o w i n g minimized h e l i u m consumption, l e s s i n f l u e n c e o f t h e e x t e r n a l noise.
1
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Magnet C h a r a c t e r i s t i c sC o i l ' i n s i d e d i a m e t e r 0.12 m C o i l o u t s i d e diameter 0.18 m
C o i l l e n g t h 1.6 m
Number o f 1 ayers 24 l a y e r s T o t a l number o f t u r n s 18 260 t u r n s
S t a i n l e s s s t e e l h o o p ' s s t r e s s 1 l a y e r w i t h r e c t a n g u l a r w i r e 2 x 3.5 mm
O p e r a t i o n a l c u r r e n t 350 A C e n t r a l f i e 1 d 5 T I n d u c t a n c e 4 H S t o r e d Energy 250 KJ Weight o f W i r e 140 daN
T o t a l l e n g t h 9000 m i n 4 p i e c e s The w i n d i n g i s vacuum-greased impregnated.
The 3 s o l d e r s i n t h e w i n d i n g a r e made w i t h t i n - l e a d (50150)
The w o r k i n g i n t e n s i t y has been c h o i c e d as t h e maximum p o s s i b l e w i t h r e s p e c t o f t h e magnetic d i s t u r b a n c e s generated by c u r r e n t l e a d s and s o l d e r e d j o i n t s between t h e c o i l and i t s s w i t c h . The t o t a l d i s t u r b a n c e on t h e a x i s i s l o w e r t h a n 10-4 x Bmax.
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Magnet Wire C h a r a c t e r i s t i c sS u p p l i e r I M I and AIRCO f o r t h e swedish d u p l i c a t e
Dimensions b a r e 2. X I . mm
Dimensions i n s u l a t e d ( f o r m v a r ) 2.1 x 1.1 mm
CopperISc r a t i o 2/ 1
Sc f i l a m e n t s : d i a m e t e r 47 microns
number 36 1
t w i s t p i t c h 25 mm
Superconductor Niobium 46 pc
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T i t a n i u mC r i t i c a l c u r r e n t a t 4.2 K and 5 T 870 A 3
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S w i t c h C h a r a c t e r i s t i c sThe s u p e r c o n d u c t i n g s w i t c h i s a s m a l l a s e l f i c s o l e n o i d wound on a f i b e r g l a s s mandrel.
The w i n d i n g i s impregnated w i t h on epoxy r e s i n 253 SCOTCHCAST ; ( e x t e r n a l d i a m e t e r 50 mm, l e n g t h 500 mm). The w i n d i n g i s done w i t h a 36 s t r a n d s (VAC FKN 6010.2 mm, CU-Nilsupra = 1.4) Copper-Nickel c a b l e (+ = 1.8 mm) w i t h a c r i t i c a l c u r r e n t o f 2000 A a t 0 T and 4.2 K. We observed a r e d u c t i o n o f a f a c t o r 2, f o r t h e c r i t i c a l c u r r e n t , f o r t h e s t r a i g h t s i n g l e w i r e s u p p l i e d compared t o t h e same w i r e i n t e g r a t e d i n t o t h e 36 s t r a n d s c a b l e .
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C o i l P r o t e c t i o n ( F i g . 5 )The quench d e t e c t o r i s t h e same as t h e SOLENO one ; i t t r i g g e r s t h e c u r r e n t b r e a k e r and t h e d i s c h a r g e o f a c a p a c i t y (20 pF under 400 V) i n t o t h e a s e l f i c s w i t c h which i n s t a n t l y f l i p s i n t o normal s t a t e ; 56% o f t h e energy s t o r e d i s dumped i n t o t h e p r o t e c t i o n r e s i s t a n c e (1.4
R)
w h i l e t h e c o i l h e a t s up t o 75'K.WWER WWLI
5
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C r y o s t a t and Cryogenics ( F i g . 6 )Low LHe consumption, t h u s maximum autonomy f o r a g i v e n s t o r a g e c a p a c i t y and easy c o n v e n i e n t o p e r a t i o n o f t h e whole cryosystem were t h e b a s i c aims o f t h e design.
C o i l and guard v e s s e l s a r e each surrounded w i t h a dual copper r a d i a t i o n s h i e l d main- tened a t r e s p e c t i v e l y 80°K and 20°K w i t h a c r y o g e n e r a t o r (CTI model 1050). The c u r r e n t l e a d s which serves o n l y t o e n e r g i z e t h e magnet a r e l a r g e l y u n d e r o p t i m i z e d :
CI-826 JOURNAL
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PHYSIQUEeach i s made w i t h 1 brass tube ( $ = 12 x 1 mm ; l e n g t h = 600 mm). The temperature o f t h e c o i l LHe b a t h may be lowered t o 2.2"K by pumping on LHe contained i n a small volume ( $ 50 mm, L 1500 mm) completely immersed i n t h e depth o f the solenoid r e s e r - v o i r .
REFERENCES
/I/ F. KIRCHER and S. BUHLER, Operation o f the superconducting solenoid SUPER SOLO and i t s s w i t c h ICEC 7
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London, J u l y 1978-
paper 3M-3./2/ J.P. SCHAPIRA, S. GALES and H. LAURENT, Un spectromPtre c o n s t i t u 6 d ' u n ou de deux solenoides cryogeniques coaxiaux. Rapport IPNO-PhN-7921, June 1979.
/ 3 / ARIANER e t al., The CRYEBIS I1 p r o j e c t , Proc. o f 2nd EBIS workshop, Orsay Saclay (1981).
