THE HEAVY ION FACILITY VICKSI AT BERLIN

(1)

HAL Id: jpa-00216597

https://hal.archives-ouvertes.fr/jpa-00216597

Submitted on 1 Jan 1976

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of

sci-entific research documents, whether they are

pub-lished or not. The documents may come from

teaching and research institutions in France or

abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est

destinée au dépôt et à la diffusion de documents

scientifiques de niveau recherche, publiés ou non,

émanant des établissements d’enseignement et de

recherche français ou étrangers, des laboratoires

publics ou privés.

THE HEAVY ION FACILITY VICKSI AT BERLIN

K. Lindenberger

To cite this version:

(2)

JOURNAL DE PHYSIQUE Colloque C5, supplément au n° \\, Tome 37., Novembre 1976., page C5-237

THE HEAVY ION FACILITY V I C K S I AT BERLIN

VICKSI-Group, presented t>y K. H. Lindenberger

Bereich Kern- und Strahlenphysik, Hahn-Meitner-Institut fur Kernforschung Berlin, 1 Berlin 39

Résumé: Hahn-Meitner-Institut â Berlin a construit un accélérateur pour des ions jusqu'à la masse A = 1*0. Le système se compose d'un accélérateur Van-de-Graaff de 6 MV type CN suivi d'un cyclotron à aimants séparés de K = 120. A présent l'institut se pro-pose une énergie de 200 MeV pour des ions entre carton et argon, avec une intensité de 100 pnA et une résolution d'énergie au-dessous de 1/1000. Le fonctionnement régulier est prévue pour le printemps de 1978.

Abstract: At the Hahn-Meitner-Institut Berlin an accelerator system for ions up to A=ltO is under construction. It consists of a single-ended 6 MV Van de Graaff followed by a split pole cyclotron with K = 120. The preliminary design aim is to reach 200 MeV for ions between carbon and argon with an intensity of 100 pnA and an energy spread below 1/1000. Regular operation is scheduled to start in Spring 1978.

GENERAL OUTLINE

The proposal /1/ to erect the heavy ion facility VICKSI at the Hahn-Meitner-Institut Berlin was made in fall 1971 , it was finally approved in spring 1973. The name stands for "Van-de-Graaff Isochron-Cyclotron Jfombination fur ^ehwere ^onen". The com-bination makes full use of our old accelerator faci-lity by taking the existing 7 MV Van-de-Graaff (ty-pe CN from HVEC) as the first stage, adding as the second stage a split pole cyclotron. The old expe-rimental hall is also used. The cyclotron is design-ed, built and run in by Scanditronix (Uppsala), all other parts of the system are taken care of by HMI. A full description of the system on which this re-port is based can be found in the Proceedings of the 7th Conference on Cyclotron and their Applica-tions (Zurich 1975) / 2 / , further details are given in the reports /3/ through /6/.

Fig: 1 shows the principle of the system. In the terminal of the Van de Graaff multiply charged heavy ions are produced. The ions are prebunched, charge state analyzed and then accelerated in the Van de Graaff to q • 6 MV. The beam matching system to the cyclotron comprises a stripper to increase the charge state to cu and two bunchers to achieve a phase width of 6 . The cyclotron is of the split pole type with k separated magnets with a mass ener-gy product K = 120 MeV. Injection proceeds in the

midplane through a nearly field free valley. The energy gain in the cyclotron is a factor 17. From this the two energy constraints of table I follow. Only for protons there is an additional limit at E = 50 MeV.

P

Table II gives the. main specifications. At first the aim is to accelerate 2 ions in the Van de Graaff giving 200 MeV final energy. For A < 25 the most abundant charge state from a gas stripper and for

11 Van de

Graaff-eye Loir on

Fig. 1: Principal Layout of VICKSI

(3)

C5- 238 K . H . LINDE

Table I : Main s p e c i f i c a t i o n s o f VICKSI Mass r a n g e A - < 40 Energy E < 1 7 - q 1 - 6 MeV ( 1 ) 2

-

₂ q2/A.120 MeV ( 2 ) Eq. ( 1 ) d e s c r i b e s energy l i m i t a t i o n by t h e Van-de-Graaff eq. ( 2 ) by t h e c y c l o t r o n . q ₁charge s t a t e b e f o r e , q p a f t e r t h e s t r i p p e r . - I n i t i a l g o a l t o r e a c h f o r masses 122A540: Energy E2

2

200 MeV R e s o l u t i o n E/AE

2

1000 I n t e n s i t y I

1.

100 p d Emittance .Q

2

5

m m a d P u l s e width T 5 1 n s A

<

50 t h a t of a f o i l s t r i p p e r can be used w i t h o u t v i o l a t i n g t h e requirement ( 2 ) i n t a b l e I . Our g o a l

i s t o achieve 100 pnA e x t r a c t e d beam w i t h 1

o - ~

energy r e s o l u t i o n . T h e o r e t i c a l l y o n l y a f a c t o r of 3 i n i n t e n s i t y i s l o s t a t t h e s t r i p p e r and a f a c t o r of 2 c o n v e r t i n g t h e dc-beam from t h e i o n s o u r c e i n t o a p u l s e d beam. A t l e a s t f o r t h e p r e s e n t s o u r c e o u t p u t w i t h n o b l e g a s e s t h i s l e a v e s a f a c t o r 10 s a f e t y margin. For q l = 1' c u r r e n t s can be much h i g h e r and

3

f o r l i g h t i o n s ( p , d , ~ e , c r ) r a d i a t i o n s a f e t y i s t h e l i m i t i n g f a c t o r a t around 1 uA.

From e q u a t i o n s ( 1 ) and ( 2 ) i n Table I it can b e seen t h a t t o g e t high energy, i o n s of h i g h charge- s t a t e q l must b e produced i n t h e i o n s o u r c e and f u r t h e r m o r e enough e l e c t r o n s must b e removed i n t h e s t r i p p e r t h a t ( 2 ) does not l i m i t t h e energy E2. I n b o t h c a s e s t h e s t r i v i n g f o r h i g h e r energy r e s u l t s i n a l o s s o f i n t e n s i t y . For t h e a x i a l e x t r a c t i o n PIG i o n s o u r c e , we a r e u s i n g now, an i n c r e a s e i n q

1 by one u n i t i s connected w i t h a l o s s i n i n t e n s i t y by a f a c t o r of roughly 10. I n e q . ( 2 ) E2,q2 and A a r e n o t independent, because t h e energy w h i l e p a s s i n g t h e s t r i p p e r i s always E / I l i a n d t h i s e n e r m t o -

2

g e t h e r w i t h t h e s t r i ~ p e r medium f i x e s t h e charge- s t a t e - d i s t r i b u t i o n a f t e r s t r i p p i n g . I t d e t e r m i n e s t h e y i e l d f o r s t a t e q2 and s o t h e i n t e n s i t y of t h e beam. Table I1 g i v e s some examples. It i s e v i d e n t t h a t an improvemant o f t h e s o u r c e o r an o t h e r i n j e c - t o r i s r e q u i r e d i f e n e r g i e s above 400 MeV a r e t o be u s e d r e g u l a r l y . The beam h a n d l i n g behind t h e cyclo- t r o n p r o v i d e s 10 t a r g e t p o s i t i o n s w i t h f l e x i b l e pre- p a r a t i o n modes f o r h i g h energy r e s o l u t i o n E/AE = 2000-10 000, s h a r p p u l s e s ( < l n s ) o r o t h e r s p e c i a l e x p e r i m e n t a l r e q u i r e m e n t s .

Table 11: Dependence of maximum energy E2 and I n t e n s i t y I on s e l e c t i o n of c h a r g e - s t a t e s q, and q2. I o n qi Ne 3 4 5

Ar

3 4 4 5 q2 S t r i p p e r 7 g a s

8

f o i l 9 f o i l 10 f o i l 11 f o i l 12 f o i l 13 f o i l E2 MeV 300 380 49 0 300 360 400 500

VAN DE GRAAFF INJECTOR

An a x i a l e x t r a c t i o n PIG i o n s o u r c e i s used i n t h e Van de Graaff

/7/

w i t h average l i f e t i m e of 180 h a s compared t o

4

h f o r changing t h e s o u r c e . It p r o v i - d e s s u f f i c i e n t beams of doubly charged i o n s . It i s

o u r f i r s t c h o i c e due t o i t s s m a l l s i z e , r e l i a b i l i t y , l i t t l e power consumption and c o o l i n g requirements which a l l a r e e s s e n t i a l i n t h e Van de Graaff t e r m i - n a l . L a t e r more complex s o u r c e s f o r h i g h e r charge s t a t e s might b e adapted t o t h e Van de Graaff t e r m i - n a l . The e x t r a c t e d beam i s focused by an E i n z e l l e n s through a mass-analyzer w i t h c r o s s e d magnetic and e l e c t r i c f i e l d s ( W i e n - f i l t e r ) f o r charge s t a t e s e l e c t i o n . Another E i n z e l l e n s and a v a r i a b l e v o l - t a g e a c c e l e r a t i o n gap produce t h e c o r r e c t shape and v e l o c i t y o f t h e beam a t t h e narrow prebuncher t u b e . A f o l l o w i n g v a r i a b l e a c c e l e r a t i o n a d j u s t s t h e cor- r e c t e n t r a n c e energy i n t o t h e a c c e l e r a t i o n t u b e and a t h i r d E i n z e l l e n s t h e f o c u s i n g . C o n t r o l o f para- m e t e r s , s y n c h r o n i z a t i o n o f t h e prebuncher and r e a d o u t o f s i g n i f i c a n t v a l u e s i s made by an o p t i c a l da- t a l i n k

/

8 / .

The Van de Graaff h a s been equipped w i t h a bakeable a l l metal-ceramics t u b e from NEC t o a c h i e v e t h e vacuum r e q u i r e d f o r heavy i o n a c c e l e r a t i o n . A pressu- r e below 5 . 1 0 - ~ t o r r h a s been achieved c l o s e t o i o n g e t t e r pumps a t b o t h ends of t h e t u b e . A s p e c i a l l y developed turbomolecular pump and a forepump t h a t t a k e t h e b u l k of t h e g a s l o a d from t h e s o u r c e a r e mounted'in t h e t e r m i n a l and s t a n d t h e 1 5 ~ atm p r e s - s u r e from t h e i n s u l a t i o n gqs. When running,beam,

, ,

t h e p r e s s u r e a t t-he e n t r a n c e of t h e a c c e l e r a t i o n t u b e , where a l s o an i o n g e t t e r pump i s s i t u a t e d , i s

(4)

VICKSI AT

BERLIN

C5-239

t h a n 10 pl~A of doubly charged heavy i o n s can b e between V a n d e Graaff and s t r i p p e r accomplish t h i s . a c c e l e r a t e d a t

6

MV and n e v e r t h e l e s s t h e danger of The e m i t t a n c e i n t h e ( x , x l ) - and ( y , y ' ) - p l a n e en- r a d i a t i o n damage t o t h e t e r m i n a l e l e c t r o n i c s i s l a r g e s from

6

rmm m a d , a s d e f i n e d by t h e ion-sour-

s m a l l . A new e n l a r g e d s p i n n i n g ( e l e c t r o s t a t i c cover c e , t o l e s s t h a n t h e acceptance o f t h e c y c l o t r o n of of t h e t e r m i n a l ) n e a r l y t w i c e t h e s i z e of t h e o l d 10 mum m a d . The elements f o l l o w i n g t h e s t r i p p e r one makes room f o r t h e new t e r m i n a l and reduces t h e guide t h e beam a c h r o m a t i c a l l y t o t h e second buncher maximum f i e l d s t r e n g t h a t t h e s u r f a c e a t

7

MV t e r - which r e f o c u s s e s it t o l e s s t h a n 6' phase w i d t h i n mina1 v o l t a g e from 25 MV/m t o 20 MV/m. Although t h e t h e c e n t e r of t h e c y c l o t r o n . The prebuncher i n t h e Van de Graaff h a s been r u n a t v o l t a g e s up t o 7.5 MV t e r m i n a l o f t h e Van d e Graaff c o n c e n t r a t e s 50

%

of i n t h e l a s t y e a r s , it was decided t o l i m i t t h e v o l - t h e i n t e n s i t y o f t h e s o u r c e w i t h i n 60° o f phase be- t a g e t o

6

MV from now on. By t h i s we hope t o g e t h i n d t h e Van de Graaff which t h e n a r e compressed: i n - very r e l i a b l e o p e r a t i o n and t o minimize t r o u b l e t o 6O a t t h e c y c l o t r o n c e n t e r w i t h o u t i i t e n s i t y from s p a r k i n g . l o s s e s . Combined w i t h t h e c . 30

%

abundance f o r t h e BEAM MATCHING

charge s t a t e s e l e c t e d a f t e r t h e s t r i p p e r t h e r e f o r e t h e o r e t i c a l l y roughly 15

%

of t h e beam from t h e i o n The beam matching,between Van de Graaff and cyclo- s o u r c e should be a c c e p t e d and a c c e l e r a t e d by t h e t r o n ( s e e f i g . 2 )

,is

d e s c r i b e d i n d e t a i l i n r e f . c y c l o t r o n . Emittance measurement d e v i c e s a l l o w t o

/g/

comprises a s main element t h e s t r i p p e r . It i s a t u n e t h e beam o p t i c s elements f o r a c c u r a t e matching g a s t a r g e t d i f f e r e n t i a l l y pumped by means o f two of t h e p a r t i c l e bunches t o t h e acceptance of t h e cryopumps, which can q u i c k l y be. ?x$hangkd f o r f o i l s . c y c l o t r o n

i ',.L..= ,

To minimize t h e i n c r e a s e i n phase space due t o angle

and energy s t r a g g l i n g i n t h e s t r i p p e r a s h a r p f o c u s CYCLOTRON

a t t h e s t r i p p e r i n time and space i s r e q u i r e d . The The main t e c h n i c a l p a r a m e t e r s a r e g i v e n i n t a b l e 111

f i r s t a y s t r o n buncher and t h e magnetic elements and a l a y o u t i n f i g . 3. The magnet system c o n s i s t s

,

_

- - - -

_

- - - I I I l I l v e r t ~ c a l beam for l ~ q u ~ d targets l o t o m ~ c physics I

(5)

C5-240 K.H.

LINDENBERGER

of f o u r C-magnets w i t h homogenizing gaps between yokes and polepieces. As can be seen from f i g . 3 t h e beam from t h e Van de Graaff i s guided by two magnets and an e l e c t r o s t a t i c i n f l e c t o r onto t h e f i r s t o r b i t . The i n j e c t i o n p a t h through t h e v a l l e y i s t h e same f o r a l l p a r t i c l e s . After a c c e l e r a t i o n t h e p a r t i c l e s a r e e x t r a c t e d by one e l e c t r o s t a t i c and two magnetic d e f l e c t o r s . S i n g l e t u r n e x t r a c t i o n s h a l l be used always. D e t a i l s on i n j e c t i o n and ex- t r a c t i o n can be found i n a s p e c i a l r e p o r t /10/. The shape of t h e magnets has been f i x e d a f t e r extensive c a l c u l a t i o n s , measurements on a h a l f s c a l e model and on t h e r e a l magnets. The base f i e l d i s w i t h i n

I O - ~ of t h e isochronous f i e l d f o r 50 MeV deuterons. The f i e l d of t h e complete magnetic s e t up including pole f a c e windings, i n j e c t i o n and e x t r a c t i o n was measured a t various s e t t i n g s such t h a t f o r any wanted beam t h e adjustments can be r e l i a b l y p r e d i c t e d by i n t e r p o l a t i o n .

The RF-system follows t h e c l a s s i c a l cyclotron de- s i g n

.

S t r a i g h t c y l i n d r i c a l r e s o n a t o r s extend r a - d i a l l y outward from t h e 36' Deltas i n two v a l l e y s , course tuning i s by moveable s h o r t s . To cover t h e frequency range 8.0 t o 10.0 MHz t h e dee capacity can be increased by moveable f l a p s i n t h e dummy dees. The Q of t h e r e s o n a t o r s has been measured t o be about 10 000.

The vacuum chamber i s octogonal with l a r g e rechtan- g u l a r f l a n g e s i n t h e v a l l e y s a t t h e o u t e r r i m f o r access t o i n j e c t i o n and e x t r a c t i o n elements, probes, and t o a t t a c h t h e RF-system. The bottom and t o p co- v e r s go through t h e homogenizing gaps between yokes and p o l e s , t h e l a t t e r ones w i t h t h e pole f a c e wind- i n g s a r e i n t h e vacuum. The main pumps a r e two cryo-

Fig.

3:

Layout of t h e cyclotron. A , B , E and F are magnetics, C and D e l e c t r o s t a t i c deflectors.

Table 111: Main t e c h n i c a l parameters of VICKSI-cyclotron SPC 120. Magnet system

4 separated C-magnets

Nominal width 50°

Pole gap .uniform 6 cm

Beam r a d i i (mid magnet) 0.45-1.89 m Sector f i e l d 0.5-1.55 T F i e l d s t a b i l i t y 5

-

1 0 - ~ Weight of one s e c t o r 100

t

T o t a l power consumption

max.

300 kW 4 main harmonic c o i l s

12 p o l e f a c e windings t o isochronize t h e f i e l d , t h e two inner- and outermost a r e used a l s o a s harmonic c o i l s .

Two independently driven i d e n t i c a l systems

Dee angle 36' Gap v o l t a g e 100 kV Voltage s t a b i l i t y I

o - ~

Frequency range 8-20

MHz

Frequency s t a b i l i t y 1

o - ~

Harmonic number 2,3,4,5,6,7 Length of r e s o n a t o r from cyclotron c e n t e r

5 m

Resonator diameter 1.5 m Rough t u n i n g moving s h o r t Fine tunfng c a p a c i t i v e Q-value -10 000 Drive 50 kV a m p l i f i e r Coupling i n d u c t i v e Vacuum system Design p r e s s u r e 1-5.10-~ t o r r 2 cryopumps ( 3 ~ ) 10 000 l / s each A l l metal s e a l e d system

Vacuum tank diameter 4.6 m Vacuum t a n k height 0.64 m T o t a l vacuum s u r f a c e

(macroscopic) 380 m 2

T o t a l vacuum volume 20 m 3

pumps a s designed f o r t h e CERN ISR by C. Benvenuti

(6)

VICKSI AT BERLIN

jeaBien t o e x t r a c t i o n including t h e matching t o t h e b e m handling systems a r e solved t o f u l l sa+$,.sf.ec- t i s n now, pending only v e r i f i c a t i o n

a

r e a l beam. Besides, i n cooperation wi$b

L.

Hagedoorn and

W. Schulte, E i n g h g ~ t i & seraiquantitative a n a l y t i a a l apprqsgh t g

$ha

srbit dynamics i s being pursued i n

order

t~

get

a

b e t t e r understanding and f e e l i n g of t h e e r b i t dynamics which

w i l l

be very valuable i n running

i n

t h e machine.

BEAM LINE

The design of t h e beam l i n e

was

governed by t h e aim t o t r a n s p o r t t h e p a r t i c l e s without l o s s i n beam q u a l i t x

md

i n t e n s i k y from t h e cyclotron t o t h e

tar-

g e t ,

buC n e v e r t h e l e s s t o have f r e e choice of t h e beaa@ropartios on n e a r l y a l l t a r g e t p o s i t i o n s . Fur- thermore we t r i e d t o g e t a system, which

i s

~;$~@qq

t o operate by decoupling t h e adjust,m,ea$,~, &P the d i f f e r e n t degrees of f r e e a m &g

nuah

a s p o s s i b l e . The system i s show.

i n

f i b ,

E

and

has been described i n d e t a i l i n r e & , $1

a /

an4 /l 3/. Most of the 10 t a r g e t p o s i t i s a s

we

reached through double mono- chroa&tez? syatems which allow f o r n e a r l y any wanted

m ~ d e

af beam

p r e p a r a t i o n . Examples of such modes a r e

d@ubIIy

d i s p e r s i v e , f u l l y achromatic o r f u l l y i s o - chrO~ous always combined with t h e possibildity t o de- f i n e energy spread and 1 i k e l y . p u l s e width by a d j u s t -

i n g

s l i t s and quadrupoles between t h e two d i p o l e magnets A and B i n f i g . 2. The g e n e r a l approach

4%

t o consider t h e combinatioh ~ of - be,y&@,$A+fft$

9 - G

Be:

t e c t o r s e t up a s a n e n t i t y and t o o p t i q ~ i $ @ $he w e r - a l l performance by ~ a r e f u ~ m a t c h i n g ,

A

a p e e i a l fea- t u r e i s t h e v e r t i c a l beam f ~ r

t i q u i 8

t a r g e t s . CONTROL SYSTEM

'P&

whole & c s e l e r a t o r and

bean handling system w i l l

be computer c o n t r o l l e d , closed loop regulation

t h ~ e u g h

t h e cempwter? however, i s not foreseen f o r t h e near f u t u r e . A schematic sketch i s shown i n fig.

4.

The a c t u a l devices a r e c o n t r o l l e d by f i v e s t a n - dard types of CAMAC modules with an a d d i t i o n a l bus f o r analog measurements. One module completely con- t r o l s one device which g i v e s a very c l e a r scheqs: The c o n t r o l desk follows t h e LAMPF, Super,

@@m

de=

s i g n . The o p e r a t o r g e t s h i s i n f ~ q & i @ ~

@%inW

through colour TV d i s p l a y s and &h&

paxw.etera

by means of touch panels and quasi-analog knobs.

I n

a d d i t i o n t o t h e standard program f o r running t h e lqachine an i n t e r p r e t e r i s a v a i l a b l e f o r easy w r i t i n g and executing of s p e c i a l programs on t h e spot. De- t a i l s of t h e c o n t r o l system a r e given i n t h e

U'

Fig.

4:

Fpi.aelple of computer c o n t r o l . reg1~)BPtS /14/ and / l 5 / .

PLANNED EXPERIMENTS

Research with VICKSI w i l l comprise t h r e e diffexent, f i e l d s : Nuclear r e a c t i o n s , hyperfine interact,$ons and atomic physics. The layout ( f i g .

3)

s h . ~ y s t h e experimental h a l l with t h e preliminary po- s i t i o n s f o r t h e d i f f e r e n t experimen.t%,

One main t o o l f o r s t u d y i n g ~ n ~ ~ 1 @ a , ~ ~ e a c t i o n s i s a magnetic spectrp@+&

$@e

Zks main proper- tie-%

9%

@.@%

4~

$&l@

IV.

90 make f u l l use of i t s

%+g$,

9@$,$e&

~ u a & $ t j

it

i s e s s e n t i a l t h a t t h e p r i -

t@+??p

beam

@an

b e , a d j u s t e d i n phase space i n such a myi,

%hat

cldispersion and emittance matching i s achieved. This means t h a t r e s o l u t i o n is gained w i t k Out l o s s of i n t e n s i t y . The Q3D w i l l be used a s a g e n e r a l purpose instrument, b e s i d e s high r e s o l u t i c n measurements it should be u s e f u l t o study low y i e l d r e a c t i o n s because of i t s l a r g e s o l i d angle and gocd

Table I V : P r o p e r t i e s of Q3D ,spectrograph. Focusing conditions Spectrometer r a d i u s Mean o r b i t radius, Angular. TB%*

8~L54

@agle

H&gaehie

field

i n d i p ~ l e a

(7)

C5-242 K.H. LINDENBERGER

background s u p r e s s i o n . I t w i l l b e equipped w i t h a e x c e p t i o n o f t h e two bunchers t h e t r a n s f e r l i n e e o m X-AE-E-t s e n s i t i v e c o u n t e r i n t h e f o c a l p l a n e .

The Q3D w i l l be complemented by a t i m e - o f - f l i g h t s p e c t r o m e t e r f o r heavy i o n s w i t h a f l i g h t p a t t l of

2 m and 200 p s e c r e s o l u t i o n . For t h i s i n s t r u m e n t i t

i s u s e f u l t h a t c y c l o t r o n and beamline can b e ad- j u s t e d i n t h e isochronous mode i n o r d e r t o g e t a p u l s e w i t h minimum time s p r e a d a t t h e t a r g e t . Hyperfine i n t e r a c t i o n s a r e s t u d i e d i n our l a b o r a t o - r y by o b s e r v i n g t h e s p i n p r e c e s s i o n o f n u c l e i i n i s o m e r i c s t a t e s , d e t e c t i n g t h e r o t a t i n g a n g u l a r d i s t r i b u t i o n of t h e d e e x c i t i n g y-rays. These expe- r i m e n t s a r e motivated by two a s p e c t s : F i r s t t o g e t s p e c t r o s c o p i c i n f o r m a t i o n on n u c l e a r s t a t e s from t h e i r magnetic d i p o l e and e l e c t r i c quadrupole mo- ments and secondly t o measure l o c a l e l e c t r i c and magnetic f i e l d s i n condensed m a t t e r . A s p e c i a l branch of t h e l a t t e r r e s e a r c h i s t h e s t u d y of l a t t i - ce d e f e c t s induced by t h e passage of heavy i o n s . Compared t o s t a t i c methods normally used i n s o l i d s t a t e p h y s i c s , t h e in-beam-observation of s p i n pre- c e s s i o n a l l o w s t o d e a l with phenomena i n t h e time regime 10 p s t o some m s . Besides s t a n d a r d equipment t h i s group p l a n s t o use a superconducting magnet g i v i n g f i e l d s up t o 10 T; f o r experiments with liL

q u i d t a r g e t s t h e v e r t i c a l beamline w i l l b e v e r y u s e f u l .

The atomic p h y s i c s r e s e a r c h w i l l b e c e n t e r e d on ob- s e r v i n g ~ u ~ e r - e l e c t ' r o n s and X-rays e m i t t e d d u r i n g atom-ion-collisions. This g i v e s i n f o r m a t i o n about t h e ' s t r u c t u r e of atoms e x c i t e d i n i n n e r s h e l l s and t h e rearrangement of e l e c t r o n s w h i l e two n u c l e i pass one a n o t h e r a t s h o r t d i s t a n c e . E l e c t r o s t a t i c e l e c - t r o n s p e c t r o m e t e r s w i t h very h i g h r e s o l u t i o n and a c r y s t a l s p e c t r o m e t e r w i l l be t h e most used t o o l s f o r t h i s f i e l d .

STATUS AND SCHEDULE

A t t h i s time - September 1976 - a l l major p a r t s ha= been manufactured and a r e now p u t t o g e t h e r on t h e s i t e . A t t h e Van de Graff t h e f i n a l v e r s i o n of t h e t e r m i n a l i s mounted a f t e r beam t u b e and column s t m c t u r e have been t e s t e d under f u l l v o l t a g e . With t h e

Van de Graaff t o c y c l o t r o n i s assembled. From t h e c y c l o t r o n t h e lower p a r t s o f t h e yokes have been mounted and one c a v i t y h a s f u l f i l l e d f u l l . power t e s t s a t 80 kV. For t h e beam l i n e t h e p a r t s a r e o r d e r e d and w i l l be d e l i v e r e d i n b e g i n n i n g of 77. The computer c o n t r o l i s about r e a d y t o b e u s e d , t h e d e v i c e s a r e hooked up t o it a s t h e y a r e i n s t a l l e d . We assume t h a t t h e whole system w i l l be p u t t o - g e t h e r and checked o u t u n t i l May 1977; f i n a l t e s t s f o r Van de Graaff and t r a n s f e r l i n e should be finish- ed 10 weeks e a r l i e r . I t may t a k e roughly h a l f a ye% more t o g e t s a t i s f a c t o r y o p e r a t i o n of t h e whole system and we hope t h a t experiments can s t a r t on a r e g u l a r s c h e d u l e around s p r i n g 1978.

REFERENCES

/ 2 / K. H. Maier, Proc. 7 t h I n t . Conf. on Cyclo- t r o n s and t h e i r A p p l i c a t i o n s , 1975, p .

68'

/ 3 / D. H i l s c h e r e t a l . , IEEE Trans. Nucl. S c i .

NS-22, No. 3 , June 75, p. 1643 / 4 / B e r e i c h Kern- und S t r a h l e n p h y s i k , H a h n - M e i t ~ r I n s t i t u t , W i s s e n s c h a f t l i c h e r E r g e b n i s b e r i c h t 1 , 1974 / 5 / HMI-report HMI-B 163, 1975

/6/

VICKSI-Statusbericht 4, i n t e r n a l HMI-report; U. Jahnke, HMI-report HMI-B 158, 1974 / 7 / P. Arndt, W. J e n t e r , and H.-E. Mahnke,

IEEE Trans. Nucl. S c i . NS-22, No. 3 , June 75, P. 1715

/ 8 / R . Conrad and W. Wawer, t o be p u b l i s h e d /9/ G. H i n d e r e r , K . H . Maier, IEEE Trans. Nucl.

S c i . NS-22, No. 3 , June 75, p. 1722

/10/ S. Lindback and H. L i n d q v i s t , F r o c . 7 t h I n t . Conf. on Cyclotrons and t h e i r A p p l i c a t i o n s , 1975, P . 226

/11/ C . Benvenuti, J . Vac. S c i . Technol. 11 (1974) 591

/12/ F. H i n t e r b e r g e r , B. Efken, G. Hinderer and

K. H . Maier, Nucl. I n s t r . Meth. 121 (1974) 525 /13/ F. H i n t e r b e r g e r , ~ ~ 1 - r e p o r t HMI-B '1 35, 1973 /14/ W. Busse, Proc. 7 t h I n t . Conf. on C y c l ~ t r o n s

and t h e i r A p p l i c a t i o n s , 1975, p . 557 / l ? / W. Busse, H. Kluge, IEEE Trans. Nucl. S c i .