COMPUTER STUDIES OF THE FIELD FOR THE SUPERCONDUCTING MAGNETIC SYSTEM OF THE DEUTERON CYCLOTRON DC-1

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COMPUTER STUDIES OF THE FIELD FOR THE SUPERCONDUCTING MAGNETIC SYSTEM OF

THE DEUTERON CYCLOTRON DC-1

S. Vorozhtsov, T. Dudareva, N. Zaplatin, E. Samsonov

To cite this version:

S. Vorozhtsov, T. Dudareva, N. Zaplatin, E. Samsonov. COMPUTER STUDIES OF THE FIELD FOR THE SUPERCONDUCTING MAGNETIC SYSTEM OF THE DEUTERON CYCLOTRON DC-1. Journal de Physique Colloques, 1984, 45 (C1), pp.C1-893-C1-896. �10.1051/jphyscol:19841182�.

�jpa-00223658�

JOURNAL DE PHYSIQUE

Colloque C1, supplkrnent au n o 1, Tome 45, janvier 1984 page C1-893

COMPUTER STUDIES OF THE FIELD FOR THE SUPERCONDUCTING MAGNETIC SYSTEM OF THE DEUTERON CYCLOTRON D C - 1

S.B. Vorozhtsov, T.N. Dudareva, N.L. Z a p l a t i n and E.V. Samsonov

J o i n t I n s t i t u t e for NucZear Research, Dubna, U.S.S.R.

R6sum6

-

^{On donne l e s} r 6 s u l t a t s d e s c a l c u l s c o n c e r n a n t l e s pa- r a m 6 t r e s d u s y s t s m e m a g n g t i q u e p o u r l e c y c l o t r o n d e 9 0 MeV

( D C - 1 )

.

Abstract

- ^In

this paper one finds the calculation results concerning the magnetic system parameters for the

90

MeV cyclotron (DC-1).

Introduction.

-

The deuteron complex

/I/

with the beam intensity 10-100 mA consists of the 15 MeV linac and two cyclotrons with the extraction energy 90 MeV and 2000 MeV respectively,

The calculations have been based on the following prerequisits:

(i) the necessary dynamic characteristics of the system's magnetic field should be provided;

(ii) each of the system's four magnets is placed within the 600 sector free of accelerating A -electrodes;

(iii) the allowable current density in the superconducting cable should be Sn accordance wLth the empiric relationship /2/:

Wj2 < / 0 2 3 3 ~ ~ r n - 4

where

W

is the store of energy,

j

is the current density in the cross sec$ion of the superconducting cable. For DC-7 at

W

^r: 5 &joule we have J 4 140 A/mm2.

Calculation 09 the Mastnet with a Flat Gae.

-

Parameters of the DC-1 magnetic system were preliminarily selec-

ted with the help of calculations carried out by the uniform magnetization method using the programme W C O D based on ref, /3/.

The computer studies of the required magnetic field were performed by choosing the curvature of the separate coil frag- ments and the configuration of the exter nal contour and the contous of cavities in pole ends, the axial ap being unchange- able (a flat gap, 2 a i = 20cm).

In

fig, 1 one can see a schematical drawing of the sector magnet with convex superconducting coils. Its basic parame- ters are listed

in

Tables 1 and 2.

In figs. 2 and 3 the mean magnetic field is plotted agaLnst the radius, and Fig. 1. Plat gap. the dynamic characteristics are plotted 1

-

^{coil, 2}

-

^pole, as a function of energy. Fig. 2 shows

3 -

^yoke,

⁴ -

^pole that in the given energy range (15-90 MeV) shape correction, stability of the circulation frequency Figures near arrows (isochronism) f, ⁼ 12,375 MHz is main-

are /U,H(T). tained with the accuracy of 9x10-~. The

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19841182

(21-894 JOURNAL DE PHYSIQUE

axial oscillatf on frequency (fig

.

³⁾

^QZ>

^1.

^I

3, starting from E > 21 MeV. One can see that after certain changes in the system

(e.g. in order to eliminate the resonance

- ^Q,

^{= 0 at E G 46 MeV}

and 3QZ =

4

at E

*

70 MeV) the dynamic characteristics of the field meet the set requirements (1 .I34 QZ (1.328 1.224 Q 2 (1.25).

Fig. 3. Flat gap. 1

-

W C O D , Fig. 2. Flat gap. 1

-

W C O D , 2

-

^{MAGSYS, 3}

-

pole shape 2

-

^{MAGSYS, 3}

-

pole shape correction.

correction.

Table 1. Basic parameters of the magnetic system.

- -

No Parameter More accu- Shaping of

Ref*'" rate flat the pole as gap variant to its

height 1. Hagnet dimensions (m) 2x1.2x2.8 2x1.2x2.8 2,4x1.2x2.8 2. Weight of the magnet iron (t) 30 3 5 35 3. Angular length of the pole

(degrees ) 17.8-30.4 17.8-30.4 19-27.8

4.

Wimal gap between poles (cm) 20 20 10

5.

Cross section of the coil (cm2)5x40=200 5x40 2x(5x18)=180 6. Angular length of the coil

(degrees 47.5-40.2 47.5-40.2 43-2-3406

7. Gap between coils (cm)

14 14 14

8. Superconductor NbTi &,=2000

A

at B=5 T, (3.5x2)mmZ

9.

Mean current density with

respect to the area of the

85

9 5 102 coil (A/mm2)

10. Ampere- turns per one

magnet (lYiA* turn ) 3.4 3.8 3.668

11.Baaximu.m field in the

magnet gap (TI 4.3

4.4

4.6

12.Store of energy (Mj oule) 5 5

-

13.&ximum linear density of

the normal force per coil 2

-

( W m 3

³

14

.&ximum linear density of

axial forces (NN/m) 1

-

^0.8

Table 2. Parameters of the internal contour of the coil.

Table

1.

The pole shape hl (r).

h2 ^t

48

cm where the pole height is h2-hl.

To check the conclusions on the system's parameters the configu- ration of the flat gap magnet was calculated by the programme MAGSYS

/$/. In this programme the field is calculated on the basis of the volumetric integral equations method.

The dashed lines in figs. 2 and

3

show the calculation results for the flat ap magnet. One can see that the mean field differs by 0.14 T (or

9%7,

isochronism is almost an order of magnitude worse ( A$/$ = 5x10-21, the axial oscillation frequency

q,7

1.13, starting from

E *

35 MeV. The results of the correction of the sys- tem's parameters (number of ampere-turns decreased by

14%,

the cavi- ty contour changed as in fig. l) show that the injection ener

li = 21

MeV

(the position of the point af/dE ^{3 0 in} fig. 2 % ~ possible. The condition Q z '7 1.

I 3

is satisf Led at E w

30

MeV.

4

12.5 0

10

147

147.5

r

3%-

spect to height the

flat gap

C

Shaping of the Pole as to Its Height.

-

Further computer studies of the field were carried out by the programme WGSYS. Comparison of the method of the field generation by shaping the pole as to its height with the flat gap variant showed the pole shaping reduces the injection energy by (2-3) NeV.

Later on it was found that the minimal gap between the poles should be reduced from 20 om to 10cm. At the same time we managed to get the configuration of the magnet which is considered to be the basic one now (fig.

4).

Parameters of this magnetlc system are given in Tables 1,2,3.

The results of the field generation in the selected version.are given in fig. 5, where the sinusoid show the position of equilibrium orbits for the injection radius

(r;

=

46.7

cm) and the particle ex- traction radius (

r

⁼ 116.6 cm). Por the magnet version under con- sideration the densfty of the reverse flux between the sectors is at the level of 0.26 T (

6%

of the field in the hill). Contribution to

angular length coordinates of the cur- vature cen- tre (X,Y) curvature radius

I

66.8769 0 39.279

9.279 11 No of

fragments

do

X(cm) Y (cm) Rc(cm) Rc(cm)

2 13.8 415.9829 216.9093 461.6 462.7

3 86.8226 -29.6522

143.75 10 10

C1-896 JOURNAL DE PHYSIQUE

ion

50

n

0

50 _{0 '50 roo I03xe. fh Z(en)}

-

Fig.

4.

Profile gap. 1

-

^coil, Fig. 5. 1

-

coil field, 2

-

^pole

2

-

^{pole, 3}

-

^yoke,

⁴ -

^{place field,}

³ -

yoke field,

B -

^mean

for R P system. field, F

-

flutter, B4

-

^{main g a r}

monic amplitude.

Qz

'

f.5 \ the mean field due to the coil is 0.75 T (N 50%). About 4% of the mean field

f 4 are due to the yoke field and, 8% are

due to the pole end (curves 1,2,3 on

1.3. fig. 4 consiquently). Deviation of the

mean field from the required one does not exceed

+ J

mT, which is close to the given generation accuracy +I mT. At thia accuracy the phase shzft of par- ticles with respect to the accelerat- ing field does not exceed +loo.

Dynamic characteristics of the equi- Fig. 6. Working point on librium otbits were calculated by the frequency diagxam. programme CYCLOPS. It is shorn that

stability of the circulation frequency in the 15-103 NeV ener range is maintained with the accuracy +*XI 0-3 (or s.03 M H Z ~

-

In the diagram of free oscillation frequen- cies (fin. 6) one can see that the owerational woint is far from dangerous resonances, apart from the-non-linear internal resonance

3 Q C = 4.

Calculations of the pondermotive forces affecting the coil show- ed that the m i m u m density of normal and axial forces is of the or- der of 2.7 ME/m and 0.5 BW/m respectively. The resultant of the for- ces attracting the upper and lower magnet coils is Fz ⁼

1.7

MN. The similar force for the poles Fz ^c 0.65 NN. The resultant of the normal forces per a coil is directed along the Y-axis and to the mag- net centre ( F = 0.15 MN). For the pole F =

0.40

&El.

The authors are grateful to Professor V.P.Dmitrievsky for the constant attention and support to the work, and to V.V.Kolga for the assistance in estimation of dynamic characteristics for the magnet system of DC-1.

References

1. GLAZOV

A.A.

et al., JlXR, P9-81-734, Dubna, 1981.

2. EBEEtHARD POX. et al. Proc.of MT-6, Bratislava (1977),v.2,p.654.

3. YANG T.E. Proc~of MT-,5, Roma (1975), p. 203.

4. AXISHIN P.G. et ale,

JINR,

E9-11859, Dubna, 1978.

5. SCWOTI W. et al., Proc.of the 1983 %rt.Acc.Conf., Santa Pe, paper S-19.