JAERI-Conf

95-021

2a4-2
DESIGN OF MAGNETS AND POWER SUPPLIES OF 3 GEV BOOSTERFORJAPAN HADRON PROJECTToshikazu ADACHI and JHP Accelerator Design Group
National Laboratory for High Energy Physics, 1-1 Oho, lbaraki, 305, Japan
Abstract
Magnets and power supplies of 3 GeV Booster for Japan
Hadron Project (JHP) have been designed. This paper describes
design concepts and the parameters of the magnets and thepower supplies.
1. Introduction
3 GeV Booster for Japan Hadron Project (JHP) is a rapidcycling synchrotron with a repetition rate of 25 Hz. Therepetition rate will be revised up to 50 Hz when an rf
acceleration system is completely installed. The Booster supplies
3 GeV proton beams into 50 GeV Main Ring, a neutron facility
and a meson facility. It comprises 48 bending magnes and 48
quadrupole magnets. The optics of this machine is described
elsewhere in this proceedings. In addition, two bending magnets
and two quadrupole magnets are needed to measure magnetic
field, which is used by a current feedback system.
Magnets are classified into three groups in accordance withtheir functions such as bending, focussing and defocussing. Eachgroup is exicited using an independent resonant network:

13.369Radius of curvature (m)0.161-0.954(T)Magnetic Field
1.75(m)Magnetic Length
280
Good Field Region (mm)-Quadrupole Magnes
0.5(m)
Magnetic Length
Radius of Good Field Region (mm) 110(T/m)
Field Gradients
0. 911 - 5. 400
Focussing Magnet QfDefocussing Magnet Qd 0.692-4.100

2-1 Bending Magnet
An aluminium stranded conductor of 30 X 30 mm2 is used
as a coil conductor of the magnet in order to reduce eddy loss. A
stranded conductor comprises a stainless pipe in the center andthin aluminium wires. Fig. 1 shows plan view of the bendingmagnet. Supposing field homogeneity of ± 5 X 10-4, a shim
was optimized by an arc (D - E) and a line (B - C - D). The
parameters of the bending magnet are listed in Table 2.

x(mmr-BM Network (for Bending Magnets},-QfNetwork (for Focussing Magnets Qf),
-Qd Network (for Defocussing Magnets Qd).

0.000

y(mm)
106.000

B 175.000

106.000

c 190.000
D 220.000
E 259.172

101.500
lOI.SOO
137.238A

Each network contains a resonant capacitor and a choketransformer for feeding a de current. Using the resonant network,
magnetic field is obtained by a superposition of the de current
and the resonating ac current or sinusoidal current.
Two kinds of feedbacks are needed in this magnet system.
One is a current feedback in order to maintain a stable magneticfield. The other is a phase feedback for 'tracking' which fixes
phases of oscillating currents of four resonant networks.
A total power of 6 MW was estimated including power
dissipation of resonant capacitors and choke transformers.

1480

2. Magnet Design. The requirements of the 3 GeV Booster to magnets are
summarised in Table 1. Here, we intend to use the same
quadrupole magnet for focussing and defocussing magnets.
Table lRequirements of the 3 GeV Booster to magnets-Proton Kinetic Energy (GeV)(Hz)-Repetition Rate-Bending Magnet

ConoEndFig. I Plan view of the bending magnet.

0.2-3.025-209-JAERI-Conf 95-021(mm)
Gap Height
Number of Tum (tum/pole)
Maximum Current (A)Minimum Current (A)(A)
de Current(A)
ac Current
series resistance (m Q)
series inductance (mH)Power dissipations(kW)de loss(kW)
ac loss

796 (Qf)
9(A)ac Current
series resistance (m Q)
series inductance (mH)Power dissipations
de loss (kW)ac loss (kW)

Table 2
Parameters of the bending magnet
212
42
1916
323
1119.5
796.5
25.6
58.1

604 (Qd)

8q
6.5 (Qd)
3.0 (Qd)

11.3 (Qf)
4.5(Qf)

3. Resonant Network
As mentioned above, magnets are grouped in accordancewith their ftmctions. Each group is excited using an independent
resonant network:-BM Network (for Bending Magnets),-QfNetwork (for Focussing Magnets Qf),
-Qd Network (for Defocussing Magnets Qd).

32.1
12.3

2-2 Quadrupole Magnet
As mentioned above, we use the same quadrupole magnet
fqr two kinds of quadrupole magnets which are required by theoptics in this machine. The magnet parameters were optimized
with respect to the specification of the Qf. Fig. 2 shows planview of the quadrupole magnet. The shape of the pole is a
hyperbola and a shim was optimized by an arc (A - B),
supposing the homogeneity of the field gradient of ± 5 X I 0"3 .

In Table 3, the parameters of the quadrupole magnet are listed.
y(nm)
x(nm)
A 160.000 ~2.813
B 201.999 49.373
A' .52.813 160.000
B' 49.373 201.999
A-A' xy =8450

The resonant network comprises magnets, resonant capacitor
and a choke transformer for feeding a de current. Fig 3 shows
the BM Network. Here, Lch is inductance of the choketransformer, C is the resonant capacitor and Lm is inductance ofthe magnets. The number of magnets included in Lm is restrictedby an allowable ac voltage. In our case, such a voltage is 10 kV.
It is easily proved that Lch, C and Lm form a parallel resonant
circuit. The number of such a circuits is called a mesh number.
For example, BM Network is 25-mesh resonant network and Lm
includes two bending magnets. The parameters of resonant
networks are listed in Table 4. Here, repetition frequency was
supposed to be 25 Hz.

Network for BendUlg M"'!!"I>
14&0

ClFig. 3 Schematic view of the BM Network.
Table 4
Parameters of the resonant networks

Fig. 2 Plan view of the quadrupole magnet.
Table 3
Parameters of the quadrupole magnet
Bore Radius (mm)Number of Tum (tum/pole)
Maximum Current (A)Minimum Current (A)(A)
de Current

130181914 (Qf)323 (Qf)
1119 (Qf)1453 (Qd)
245 (Qd)
849 (Qd)

BMNetwork
Number of Mesh
Number of Magnets (/mesh)(mH)
Lm(mH)
Lch(mF)c(A)de Current(A)
ac Current

-210-

25
2
29.05

t

58.1
2.09
2239
1593(magnet)

JAERI-Conf 95-021(mF)-Cf(mH)-Lf(mH)-Lp-Choke Stepup Ratio

2389.5(capacitor)
7.27
3210
1665

Peak Voltage (kV)(kW)
de loss(kW)
ac loss
QfNetwork
Number of Mesh
Number of Magnets (/mesh)(mH)
Lm(mH)
Lch(mF)c(A)de Current(A)
ac Current
Peak Voltage (kV)de loss (kW)ac loss (kW)
QdNetwork
Number of Mesh
Number of Magnets (/mesh)(mH)
Lm(mH)
Lch(mF)c(A)de Current(A)
ac Current

inductance Lm

---5
5
44.5
89.0
1.37
849
604(magnets)
906( capacitor)
4.22
325
154

Fig. 4 Schematic view of the pulse power supply.
Concluding Remarks

is reduced to one-tourth.

4. Power Supplies

Table 5Ratings of de power supplies

BMQf
565
503
1119

In order to realize the magnet and power supply system of
the 3 GeV Booster, there are many problems to be solved. At
first, magnet size is very huge, which makes accurate stacking ofthin iron plates so difficult. Therefore, large-scale and accurate
stacking method must be established. An aluminium stranded
conductor of 30 X 30 mm2 is used as a coil conductor. Since astranded conductor requires a larger radius for bend than aradius of a hollow conductor, a free space between magnets may
be shortened. This problem, however, is solved by using astranded conductor with smaller size.
Concerning the power supplies, the most important
problem is to establish a feedback method. Especially, there isno established method by which large-scale and independent
resonant networks are operated synchronously. Now we arepreparing an R & D in order to fix a feedback method by which
phases between two resonant networks are adjusted.

4-1 de Power Supplies
Ratings of de power supplies are listed in Table 5.

3210
1433
2239

Qd
325
382
849

4-2 Pulse Power Supplies
A schematic view of a pulse power supply is shown in Fig.
4. Parameters of the elements shown in the figure are listed inTable 6.
Table 6
Parameters of elements of pulse power supplies
Name ofNetwork-Power (kW)
(V)
-VsBM
1665909

2.37
273
1.90
4llffi

5.56
565
232

T~-:~~:-~~~~~~~~-:~-~:-~~~:~~~-~:i~:-:;~~-~~=~-:;~t--:eName of Network(kW)-Power-Voltage (V)-Current (A)

8

2.04
317
2.20
45
5
44.5
89.0
1.37
1119
796(magnets)
1194(capacitor)

Peak Voltage (kV)de loss (kW)ac loss (kW)connected parallel so that the34.5
18.8
0.13

Qf232
1390

Qd
154
1060

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