JAERI-Conf 95-021

PA31
DESIGN OF SOLENOIDAL MAGNETS WITH LAMINATED CORES
E.Tanaka*,s.Yamada,T.Murakami,A.Kitagawa,H.Ogaw a,T. Fukushima*, T. Kimura* ,O.Morishita **, T. Sakata**, K. Sawada**
National Institute of Radiological Sciences (NIRS),4-9-1 Anagawa,Inage-ku,Chiba 263*Accelerator Engineering Corporation,2-10-14 Konakadai,Inage-ku,Chiba 263**sumitomo Heavy Industories,Ltd.,S-2 Soubiraki,Niihama,Ehime 792

designed and assembled.

Abstract
HIMAC (Heavy Ion Medical Accelerator inChiba), which is the first heavy-ion
accelerator facility for medical use in theworld, is in operation at NIRS. A project oftime-sharing-operation of the injecto.l::' is inprogress and a solenoidal magnet with alaminated core is designed and assembled forthe time-shearing-operation of the injector.
Specifications and results of magnetic-fieldmeasurement are described.
Introduction
The HIMAC facility can be divided into
three parts; the injector, the synchrotron
with two identical rings, and the irradiation
system with horizontal and vertical-beamlines. The injector comprises two kinds ofion sources ( ECR and PIG), two kinds oflinear accelerators ( RFQ andAlvarez linac),and beam-transport systems. The linacs
accelerate various ions of 8 keV/u, ranging
from He teAr, up to 6MeV/u. Amedium-energy
beam line, in cooperation with two pulse- .
operated magnets, can supply beams to.three
beam lines, i.e. two synchrotron rings anda medium energy experimental room ( seeFig .1 ) , 'simultaneously', changing the beam
directions from pulse to pulse.
In order to increase the versatility of
the facility, the time-sharing-operation of
the injector, i.e. acceleration of different
kinds of ions from pulse to pulse, was studied
and the project is in progress. In the present
case operating parameters of all devices will
be adjusted to the optimum values so that ionswith values of largely different q/A can beaccelerated. All the magnets and monitoring
devices in the beam transport line must,
therefore, be replaced by those bearing
pulsed-operation. Since a solenoidal magnetof De-operation is installed in the lowenergy beam-transport line, in addition to
the electro-static quadrupole lenses, a newsolenoidal magnet with a laminated core isStructure of the solenoidal magnet
Specifications of the solenoidal magnet
are listed in Table 1 and its dimensions andstructure are displayed in Fig.2. A coil of288 turns with a current of 350 A generates
maximum magnetic field of 6.8 kGauss at thecenter. A water-cooled coil is made of thehollow copper conductors. A magnet core
consisted of two types of segments, Core-Aand Core-B (see Fig.2 ), both of which are
made of 0.5 rom thick steel plates coated withelectrical insulators. The Core-A is a pile,
25 rom thick, of octagonal plates and is fixedto the Plate-A being made of SUS304.
Rectangular plates of 65 rom X 218 rom in sizeare piled up to form eight pieces of Core-Bs;
six of them are 160 rom thick and two of themare 130 rom thick. Each one is tightened bybolts and Plate-Bs, then fastened to theplate-A. The coil is also fixed to the Plate-A
with supporting rods.
All the components, cores and the coil,were bolted, and no welding method wasemployed. It is, therefore, free from thestrain induced by the welding. End faces ofthe coil, which define the spacing betweenPlate-Bs, were carved with accuracy of ;;;; 0.2
rom. Overall accuracy is within ±O. 5 rom bycontrolling torque of the bolts. Omission of
the welding process can cancel out theadditional cost due to longer machining andassembling processes.
Magnetic-field distribution
Measurement of magnetic-fielddistribution was carried out. The current
source was operated in a DC mode. An exampleof the field distribution is shown in Fig.3
for the cases of I = SO, 100, 150, 200, 250,300, 350 A. An effective field length wascalculated to be 180 rom. Relation between themaximum magnetic field ( Brnax ) and theelectric currents ( I ) is plotted in Fig. 4.

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The Bmax values linearly depend on thecurrent values, so that saturation effectinside a core seems to be negligible small.
The Bmax of 6.915 kGauss obtained with thecurrent of 347 A is strong enough comparedto the specification.
Laminated cores of solenoidal magnets
have more complicated structure then that ofordinary dipole magnets. Our design of thenew magnet can be one of the solution.

Table 1The specifications of the solenoidal magnet

References(1) A. Kitagawa, et al., The 5th Japan-China
Joint Symposium on Accelerators for Nuclear
Science and Their Applications. (1993)

Coil length
Bore diameter

218 nm
110 nmMaximum magnetic field
Maximum magnetomotive
Turns
Maximum current
Maximum voltage (at 20'C)
Maximum power (at 20'C, DC)

6.87 kGauss
1X105 AT
288 turns
347.2 A
34 v
11.8 kW

Cooling water circuits
Pressure drop
Water flow
Water temperature rise

8
3 kg/cm2

14.2 1/min
12.5 deg

ECR Ion Source

PIG Ion Source

RFQLinac

Low-Energy
Beam-Transport LineFig.l Layout of the injector- 113-PIG Ion Source

JAERI-Conf 95-021

Plate-B.
Supporting Rod/A--Fig.2 Structure of the solenoidal magnet

7000 -- 6000
Cll-~~ 4000-!

~=Ill 2000

-200

00z(mm)Fig.3 Magnetic field distribution. - 114-~0/-v/

r---·--·-

100200//

I300

I (A)
Fig.4 Relation between Bmax and I