Induction Acceleration for Beam-Orbit Control
誘導加速による電子ビーム軌道の位置制御

広島大学理学研究科
物理科学専攻M1179029

松野 聖史

Department of Physics, Faculty of Science, Hiroshima University

Seiji Matsuno
2000-2001

Abstract

The electric field E induced by a varying magnetic filed can be used for acceleration.
Suppose, an electron makes a circular orbit surrounding a magnetic flux Φ which is changing
with time. According to Maxwell equations,dΦ∫ E ⋅ d l = − dt , where the line integral is along

the electron orbit, i.e. the acceleration voltage per turn is expressed by the flux change. A
well-known example of application of this scheme is the betatron.
In this paper, application of this acceleration scheme to a 150 MeV electron ring at Hiroshima
University is studied.
The electron beam injected by microtron loses its energy by 59.7 eV per turn due tosynchrotron radiation. As the ring has not any accelerations instruments, the beam orbit moves
toward the inner wall of the vacuum pipe. It is about 3 ms from the time of injection to the
dumping against the beam pipe. If the loss energy of the beam is compensated by induction
acceleration, the beam can keep circulating for longer time.
To induce the accelerating electric field, a troidal coil wound on an iron core is placed acrossthe electron beam line. It is necessary that d Φ /dt is constant during the operation. The
maximum value of Φ is determined by the saturation and the cross section of the corematerial. The iron core saturates at about 2 Tesla. In order to keep the constant acceleration
voltage for 6 ms, the cross section of the iron core should be more than 0.12 m2. It is very big
size and heavy; total core weight is about 2 ton.
The inductance L of the troidal coil is not constant as the magnetic permeability µ of theelectromagnetic steel sheet depends on the B-H hysteresis curve. To make the constant alterationof the magnetic field, we need to shape the current pulse form in accordance with the variationof the µ . A variable current supply that can make a rapid pulse with an arbitrary is necessary.
We made a software which can program the current form on general Windows OS for a
Yokogawa DAC module. We also designed a small-sized model of an induction magnet, whichhas 1/8 cross section of the iron core to be installed. Combining the software and the small-sizedmodel, the magnetic permeability of the core material is measured to determine the mostsuitable form.

2

Contents
Abstract
Chapter 12Introduction

Chapter 2
2.1
2.2
2.3

Possible application of induction acceleration
to REFER
The 150 MeV electron ring REFER
The present situation of REFER
The improvement plan

4

5
5
6
8

Chapter 3 The application of induction acceleration
scheme to REFER 9
3.1 The principle of induction acceleration
9
3.2 Saturation of the core material
9
3.3 The B-H curve11
3.4 Determination of magnetic permeability
12
3.5 The energy conservation
14
3.6 A current form generator
17
Chapter 4 Experiments, Results, and Discussions
4.1 The magnet cores
4.2 Setup of the experiments
4.3 Results and Discussions

18
18
19
20

Chapter 5

27Conclusion

Acknowledgements

28

References

29

Appendix
A Software for Yokogawa DAC module

30
30

3

Chapter 1
Introduction

New types of induction accelerators are recently attracting interest: A novel induction
acceleration in a fixed-field alternating-gradient magnet was proposed by T. Ohkawa etal. It was the first application of this scheme to a circular accelerator [1][2]. Anotherexample is a 3.6 MeV induction LINAC constructed in collaboration of High Energy
Accelerator Research Institute (KEK) and Japan Atomic Energy Research Institute(JAERI). Now, the induction synchrotron for KEK 12 GeV Proton Synchrotron is being
constructed [3][4][5]. To accelerate protons up to 12 GeV is a hard task and we need todevelop many big induction magnets and switching systems for high frequency current.
On the other hand, with this scheme we can easily give a small amount of energy
enough to compensate the synchrotron radiation loss at a small-scale circular storage
ring. We can also control the position of the beam orbit by adjusting the accelerating
voltage.
We examine the applicability of such an acceleration scheme to a 150 MeV
small-scale electron ring at Hiroshima University which is called REFER, Relativistic
Electron Facility for Education and Research.
In Chapter 2, we discuss about the actual situation of the REFER ring and thesignificance of application of induction acceleration. In Chapter 3, we discuss about thepossible difficulties to be overcome. In Chapter 4, we discuss about the measurement
using the small-sized model of an induction magnet.

4

Chapter 2
Possible application of induction acceleration to
REFER

2.1

The 150MeV electron ring REFER

REFER is an electron beam ring at Hiroshima University in which an electron beam
goes along the circular orbit of circumference of 13.5 m. This ring has neither anacceleration structure nor an electron gun. It accepts a 150 MeV electron beam from a
microtron that belongs to Hiroshima Synchrotron Radiation Center, Hiroshima
University (HiSOR).
The injection beam parameters depend on those of microtron as shown Table1-1 [6],while Table1-2 shows the REFER basic parameters [7].
Output Beam Energy
Input Beam Energy
Peak Beam Current
Beam Pulse Width
Repetition
Beam Emmitance
Energy Dispersion
Mag. Field of Bending Mag.
Magnetic Field Gradient
Pole Gap of Bending Mag.
Number of Turns
Energy Gain per Turn
Accelerator Structure
Accelerator BoreRF Frequency
RF Field Gradient
RF Wall Loss
Beam Loading

150 MeV
80 keV
2-10 mA
0.2-2 μsec
0.2-100Hz
0.5πmm-mr ( 1σ)±0.1％ ( 1σ)1.23 T
0.14 T/m
10 mm
25
6 MeV
8 Cell Side-Coupled Cavity
10 mm2856 MHz
15 MV/m
1.5 MW ( Max. )2.0 MW ( Max. )Table1-1 The microtron parameters

5Electron Energy
Length of Beam Orbit
Long Straight Section
Short Straight Section
Field of Bending Mag.
Radius of Curvature
Frequency
Horizontal Tune
Vertical Tune
Number of Bending Mag.
Value n of Bending Mag.

150 MeV13.5 m2.5 m
0.7 m
0.67 T
0.75 m10-100 Hz
1.39
1.65
8
0.55

Table1-2 The REFER basic parameters
This ring is used to study parametric x-rays, laser compton scattering, and thedevelopment of a x-ray source based on new mechanism. The ring has an inner target
set in a vacuum chamber placed on the beam orbit.

2.2

The present situation of REFER

The electron beam injected by the microtron loses its energy by 59.7 eV per turn due
to synchrotron radiation. As the ring has not any acceleration instruments, the beam
orbit moves toward the inner wall of the vacuum pipe.
The upper photographs in Fig.2-1 show typical examples of images recorded by asynchrotron monitoring camera. The bottom shows the oscilloscope output of the ring
current monitor. The horizontal axis is the time in 1.00 ms/div. The vertical axis is theoutput voltage of the current monitor in 1 V/div. It can be converted to the circulating
current using a conversion factor measured in a previous experiment [8]; 5 V on thecurrent monitor corresponds to 100 mA.
The time indicated as (a) in Fig.2-1 is the beam injection time. From the injection
time to 0.5 ms voltage changes from 0 V to about 5.5 V. This part of the curve isgoverned by the rise time of the electronic circuit and does not necessarily reflect thepulse shape of the beam current. According to Fig.2-1 at the point (b), about 1.5 ms
after the injection, voltage is about the half of the maximum. The photograph (b) of theupper part of Fig.2-1 is the beam orbit observed at the time (b). The right side of thephotograph is outward side of the ring and the width of the photograph corresponds to
30 mm in the actual space. Comparing (a) with (b), the beam intensity is high and the6beam orbit is in the right side at the time (a), and at the (b) the beam intensity is lower
and the beam orbit has moved toward the inner side of the vacuum pipe by about 15 mm.
It is about 3 ms from the time of injection to the dumping against the beam pipe.

(a)

(b)

Fig.2-1 The photographs of the synchrotron monitor and the current monitor

7

2.3

The improvement plan

We want to improve the REFER ring, at least in the following 2 points.
(1) To increase the beam life time(2) To make the orbit radius constant without depending on time
In our plan the loss energy 59.7 eV per turn due to synchrotron radiation of the beam
is compensated using the scheme of the induction acceleration. If the loss energy of thebeam is properly compensated by induction acceleration, the beam can keep circulating
for longer time. Furthermore, we will be able to control the beam orbit by adjusting therate of the flux change in the induction coil.
Another point is that we may possibly reduce the unwanted radiation caused by thecollision of the low energy electrons with the vacuum pipe by properly controlling thebeam dumping time.

8Chapter 3
The application of induction acceleration
scheme to REFER

3.1

The principle of induction acceleration

The principle of induction acceleration is derived from the Maxwell equations. The
electric field E induced by a varying magnetic filed flux is related to theelectromotive force V0 in the following way;dΦ

∫ E ⋅ d l = (−) dt = V .
0

(3-1)

This means that an electron is accelerated by eV0, if it makes a circular orbit, following
the integration path in (3-1), surrounding a magnetic flux Φ that is changing with time.
For applying to REFER we require the voltage V0 to be 59.7 V.

3.2

Saturation of the core material

To induce the accelerating electron field, a troidal coil wound on an iron core isplaced across the electron beam, as schematically illustrated in Fig.3-1.
RH = 0.45 m

I

RV = 0.35 m

rH
RVrH = 0.3 m

rH

rV = 0.4 m
RH
rV

Fig.3-1 The troidal coil for REFER

9The iron core size is determined the maximum value of the magnetic flux density B.
dΦ
is constant during at least 3 ms. The
dt

As described in Chapter 2 it is necessary thatmaximum value of Φ is determined by the saturation and the cross section S of thecore material.
According to Φ = BS , S = rHrV = 0.12 m2 ,V0 =dΦ SdB== 59.7
dt
dt
.
dB
≈ 497
dt

(3-2)

With the knowledge that the iron core saturates at about 2 Tesla, we have;∆B = 497 ∆t < 2 Tesla.
∆t < 4.02 × 10 -3 s

(3-3)

Thus, the iron core saturate after about 4 ms.

2 T-4 m s
4 ms

t

-2 T

Fig.3-2 During 8ms the beam can accelerate
If the initial value of B starts from –2 Tesla, during total 8ms the beam can be
accelerated in the same electric field strength. (Fig.3-2)
The iron core, which has the cross section 0.12 m2, is very big size and its weight isabout 2 ton.
According to the Ampere’s law,

∫ H ⋅ d l =HI1

lH = NI 1
H=

(3-4)

N
I1
l

where H is the magnetic field, N is the turn number of the troidal coil, and the line10

integral is along the magnetic flux i.e. l is the average length of the core.
The magnetic flux Φ that goes through the coil is expressed byNS
I1lwhere µ is the magnetic permeability of the core material.
Φ = BS = µ HS = µ(3-5)

The inductance L of the coil is
L=µ

S 2
N .
l

(3-6)

If L does not depend on time, a constant electron field 59.7 V to accelerate theelectron beam per turn might be achieved by satisfying the relations
1 dI 1dΦ
=L= 59.7
dt
N dt
.
dI 1
N
A/s
∴
= 59.7 ×dt
LV0 = ( − )(3-7)

Obviously, the above considerations are not enough to determine the rate of change ofthe magnet current I1 because the inductance is time dependent due to the nonlinear B-H
relation as discussed in the next section.

3.3

The B-H curve

In this section, we study the dependence of the B-H hysteresis of the core material.
The inductance L of the troidal coil is not constant as the magnetic permeability µof the electromagnetic steel sheet depends on H. In the induction acceleration we must
supply a rapidly varying current pulse to the troidal magnet. Ordinary iron cores sufferfrom the effect of the eddy current. We need the iron core that has a less effect of theeddy current and we chose the electromagnetic steel sheet of silicon steel is
KAWATETSU 30RG120. We make a core by stacking the 0.3 mm thick sheets withvarnished insulator on the surface.
Fig.3-3 is a model hysteresis curve approximated by an arc-tangent function imitating
the data of 30RG120 in the catalog [9]. The horizontal axis is H in A/m and vertical is B
in Tesla. This function is11 H −b
B = a tan −1 
.
 c 
(3-8)
 a = 1.114
 b = 6.2
 c = 2.232
In this consideration the current goes up only and the value of the core saturation is1.75 Tesla. When the current goes down the B-H curve is different from (3-8).
2B [Tesla]
1

0

-1

-2
-40

-30

-20

-10

0

10

20

30

40

H [A/m]Fig.3-3 A model hysteresis curve of 30RG120 when the current goes up only

3.4

Determination of magnetic permeability

The coil turn number to be installed beam line is 2. (N = 2) From Ampere law the
relationship between H and I1 isN
I 1 = 1.25 I 1 .
l
As the magnetic permeability µ is the inclination of the B-H curve,
H=

µ=

∂B
=
∂H

(3-9)

a

(3-10).
2
 H −b
1+ 

 c 
According to Fig.3-3, we see that µ is almost constant at the neighborhood of thepoint of B = 0. Thus, µ B =0 =∂B
= a = 1.114 , we regard as the inclination is∂H B =012

constant. To make the induction acceleration voltage 59.7 V,

dI 1
is
dt

dI 1
N
l
= 59.7 × = 59.7 ×= 357.2 A/s .
dt
L
µ NS

(3-11)

Combining the model B-H curve anddI 1dΦ= 357.2 A/s ,alteration plots isdt
dt

shown in Fig.3-4. The left vertical axis isdΦV (red line plotted), the right verticaldtaxis is I1 A (blue line plotted), horizontal axis is time. The numerical result shows theterritory ofdΦdΦ= const is few, thus the dependence of µ appears
alterationdt
dt

directly. In the experiments we measure directly
determine µ by getting thedΦvalue alteration. So, we can
dt

dI 1
dΦ
is constant.
alteration whendt
dtdΦNS dI 1=µdt
l dt
1 dΦ .
lµ=NS  dI 1  dt
 dt 

(3-12)

70ｄΦ 6 030

I[V] 5 0

I
[A]

20

40
10
30
20

0

ｄΦ

10
0

-10
0.00

Fig.3-4

0.02

0.04

0.06

0.08

0.10

dI 1
dΦ
= 357.2 A/salteration plots in
dt
dt

13

3.5

The energy conservationdI 1
and V1 are determined independently from the beam current I2 todt
accelerate. The beam-energy loss by the synchrotron radiation is directly proportional to
In section 3.4,

the value of the beam current, on the other hand the providing power V1I1 is notconcerned with I2 at all. We wonder about the energy relationship between revenue andexpenditure. In this section we discuss about the energy conservation. We use a
simplified model which is shown as an equivalent circuit in Fig.3-5.

I1

I2

V1

V2

C u rren t
S u p p ly

C u rren t
S u p p ly

n1n2

C o re len g th l
C ro ss sec tio n S

Fig.3-5 The simple model to estimate the energy conservation
The left hand side shows the current supply and a troidal coil which has a corecross-section S and a core average length l. The core is made of ideal magnetic material
with constant magnetic permeability µ and can store limitless magnetic energy. The
current supply is the ideal current supply element. I1 is the current value and V1 is thevoltage across the coil whose turn number is n1. Φ is the magnetic flux through thecore magnet cross-section. The right hand side of Fig.3-5 represents the electron beam.
The current supply makes the current form shown in Fig.3-6 (c), the current value I2
corresponds to the beam current. n2 is the turn number of the coil, in this case n2 = 1. V2is the induction acceleration voltage V2 = 59.7 eV.
The magnetic flux Φ is
Φ = BS = µ HS =µS
(n1 I 1 + n2 I 2 ) .
l(3-13)

14

The voltage produced by the time variation of Φ isV1 = n1

dI dΦ n1 µ S  dI 1=
+ n2 2  .
 n1dt
l  dtdt (3-14)

V2 = n2

dI dΦ n2 µ S  dI1=+ n2 2  .
 n1dt
l  dtdt (3-15)

From V1 and V2,
V2 =

n2
V1 .
n1

(3-16)

Suppose we give the one period triangle current form I1,

2b 


0 ≤ t ≤ at − ba .
(3-17)
I1 = 
4b 
 2b
 − at + 3b
≤t≤



a 
 a
I1 current form is shown in Fig.3-6 (a). The derivative of I1 is shown in (b). During
the period 0 ≤ t ≤

2b
2b
4b
the beam current is constant I2 = I2 and during
≤t ≤
the
a
a
a

dI 2
is shown in (d). In
dt
Fig.3-6 (d), spikes due to the derivative of step functions, i.e. delta functions, show up.
beam current is 0. I2 current form is shown in Fig.3-6 (c) andV1 and V2 are derived from I1 and I2 current forms, which are shown in Fig.3-6 (e)and (f), respectively. The power at the instance is shown in (g) and (h).
The energy conservation at the moment is
V1 I 1 + V2 I 2 =dE magdt
where, Emag is the stored magnetic energy in the core iron magnet.
The time integration from 0 to

(3-18)

4b(one cycle) isa∫ V1 I1dt + ∫ V2 I 2 dt = ∫dE magdt .
(3-19)
dt
In the integrated power of V1I1, contributions from two spikes of the delta function,(shown on Fig.3-6 (g)), add ups to be
2n n bµ SI 2
 n1 µ S.
bn2 × ∫ I 2δ (t ) dt  = − 1 2ll∫ V I dt = 2 ×  −1 1

(3-20)The integrating power of V2I2 remains the area of the rectangular. (shown on Fig.3-6
(h))

15

∫ V I dt =2 2

n1 n2 µ Sa
2b 2n1 n2 bµ SI 2
× I2 ×=.
lal(3-21)The equation (3-19) is∫ (V1 I1 + V2 I 2 )dt = ∫dE magdt = 0 .
dt
After the one cycle the magnetic energy Emag is reset.
d I1
dt

I1
b
4b
a

0

2b
a

-b

a

t

4b
a

0

2b
a

-a

t

(b)

(a)
d I2
dt

I2
I2

I2

0

4b
a

2b
a

t

2b
a

0

4b
a

t

(d)

(c)

V1

V2
n 12μS alt

0n 1 n 2 μS al0n 12μS altn 1n 2μS a
l
(f)

(e)

Pow er
V1 I 10(3-22)

V2 I 2
2b
a
4b
a
(g)

t

0

2b
a

4b
a

t

(h)

Fig.3-6 The supplement figures to estimate the energy conservation

16

3.6

A current form generator

To make the constant growth of the magnetic field, we need to shape the current pulse
form in accordance with the variation of µ . As we control the current supply using a
DAC module, we make software for the Yokogawa DAC module (WE7000 series). We
made it on the general OS Microsoft Windows Operating System so that everyone caneasily use it..
Basic operation of the software is such that at a specified time the corresponding
current value is sent to the DAC module. The program was coded in Borland C++
Builder 4, using Windows DLLs of Yokogawa module control. DLL, Dynamic Link
Library, is made from functions that can be used in various programming languages. We
can use the functions including the DLLs by making declarations in the first section of
the program.
More detail of the usage of DLLs is described in Appendix. In Fig.3-7 shown is thecontrol window of the first version. Through this window, it is possible to send a control
command to the module, to get the value of the current voltage of the module, and to set
an arbitrary value used in a manual operation.

Fig.3-7 A software of controlling the DAC module

17

Chapter 4
Experiments, Results, and Discussions

4.1

The magnet cores

We observed the voltage produced by the induction acceleration using two small
model-magnet cores. The first one is made from ordinary steel sheet of 10 mm thickness.
The shape and the size are shown in Fig.4-1. The left hand is the drawing and the rightis the photograph.
10

140

50
[m m ]

140

Fig.4-1 The small magnet core made from ordinary steel
The second one is the 1/8 model that has 1/8 cross section of the magnet to beinstalled, which is proposed in Chapter 3. It is made from the same material as the oneused for the magnet core to be installed; 30RG120 electromagnetic steel sheet. This
could be installed to the REFER beam line because its height is the same as that of thebeam line and the central hole allows the beam pipe to go through. Theoretically if this
1/8 model were installed to the beam line, the electron would be accelerated by 7.46 V
per turn during about 8 ms. The 1/8 model is shown in Fig.4-2.

250

50
150

350

150

[m m ]

Fig.4-2 The 1/8 model magnet made from 30RG120

18

The right hand is the photograph of the 1/8 model. The author of this work, who is
170 cm tall, is standing near by.

4.2

Setup of the experiments

Setup of the experiments is shown in Fig4-3.

re m o te
P u lseG e n era to r
C u rre n t
S u p p ly

m ag n et c o reI1

o u tp u t

n1

n2

0 .1Ω

O s c il l o s c o p e
ch1

ch2

Fig.4-3 The setup of the experiments

We use a current supply and a pulse generator as the high frequency pulse supply.
This current supply can be controlled by an analog remote pulse, if we want 1 A output,
1 V receives the remote terminal of the current supply. In this experiments, we requiredI 1
is constant during a pulse width, the pulse shape for the remote controllingdt
input is taken to be triangular.
thatThis current supply output range is –5 A to 5 A, –35 V to 35 V. On the oscilloscope,ch1 is the coil ampere monitor measured by the voltage across a resister of nominal
resistance 0.1 Ω . It turned out, however, that its resistance is 0.14 Ω by themeasurement with a resistance meter.
In the output of the digital oscilloscope the yellow line is the ch1 input, the green lineis the ch2 input. In Fig.4-4 ch1 is the output of the pulse generator voltage whichindicates the output ampere of the current supply. Ch2 is the voltage across the resister19

shown in Fig.4-3. From theses outputs, we see that the resistor voltage 700 mV
corresponds to 5 A.

Fig.4-4 The coil ampere monitor from the voltage
In Fig.4-3 n1 and n2 of the magnetic core are turn numbers of the coil, respectively.
The coil current through the n1 turn coil is I1. The small ordinary steel core has 40 turns
for n1 and 35 turns for n2. The 1/8 model has 2 turns for n1 and 10 turns for n2. The
purposes of this experiment are (i) the measurement of the magnetic permeability µ of
the material used for the core, and (ii) the measurement of the acceleration voltage
produced by the

4.3

dI 1
alteration.
dt

Results and Discussions

Using the small general steel core, we supplied triangular wave current obtained fromthe pulse generator. Fig.4-5 (1) is 10 Hz pulse, Fig.4-5 (2) is 50 Hz pulse. Fig.4-5 (3) isµ calculated with the formula (3-12) using the 50 Hz data.
The µ curve shows unexpected results. Especially, µ should be only plus orminus value, while the results show µ takes both plus and minus values. Furthermore
the maximum value of µ shows about 2 × 10 −7 . Comparing general steel magnetic
permeability is 4π × 10 −4 , the result is unreasonably small. And the result is smaller20than a vacuum magnetic permeability 4π × 10 −7 . The measurement of µ shows under
the field strength –385 < H < 385 A/m. In this region the core material is not saturated.
The behavior of induced voltage from the ordinary iron core could not be explainedby an expected B-H curve. This suggests that some other effect, such as the eddy current.
One of the way to research other effects is that we should measure the magnetic flux
behaviors of within the core material.
The results of the experiments with the 1/8 model magnetic core are shown in Fig.4-6.
Fig.4-6 (1) is the result with the 100 Hz triangle pulse, Fig.4-6 (2) is 500 Hz pulse.
Fig.4-6 (3) is µ alteration plotted for 100 Hz.
According to Fig.4-6 (3) the µ is the constant value about 0.1 H/m. This result isreasonable judging from the B-H curve shown in Fig.3-3. At this ampere range, theelectromagnetic steel sheet is not saturated under the field strength –12.5 < H< 12.5
A/m. The maximum value 1.114 of µ given in the data sheet of the steel supplier is
not observed.
On the other hand, the µ alteration, derived from the 30RG120 fitting curve of
Fig.3-3 under the field strength –12.5 < H < 12.5 H/m, is shown in Fig.4-7. The part of
Fig.4-6 (3) fall under the same field is shown in Fig.4-8. In Fig.4-7 µ is changing with
H but in Fig.4-8 µ is almost constant. These results do not look like on the shape.
One of the reasons of inconsistency is the B-H curve mismatch. The B-H curve of thecatalog derived from a sheet testing, the saturation value of the B is 1.75 Tesla. In thiscase the core does not arrive at the saturation point, while we do not know the initialsituation of the B-H curve clearly in the experiment. To avoid them we should make theinitial state of the define B-H curve, and to saturate the material we need the current
supply which has a wide range: –20 to 20 A, or n1 and n2 turn number should be muchchanged. However, the value of the µ with the 1/8 model is reasonable. The 1/8
model may be able to be used for induction acceleration.
This current supply has the characteristic that the flat part appears during any time
when ampere crosses the point of 0 A. This effect appears conspicuously in Fig.4-6.

21

(1) 10 Hz triangle pulse output(2) 50 Hz triangle pulse output
Fig.4-5 Using general steel small core22

0.00000050

μ [H/m]0.00000025

0.00000000-0.00000025-0.00000050-0.010-0.005

0.000

0.005

0.010

0.015

t [s]

Fig.4-5 (3)µ in 50 Hz pulse

23(1) 10 Hz triangle pulse output(2) 500 Hz triangle pulse output
Fig.4-6 Using 1/8 model magnetic core

24

0.50

μ [H/m]

0.25

0.00

-0.25

-0.50
-0.010-0.005

0.000

0.005

0.010

t [s]

Fig.4-6 (3)µ in 100 Hz pulse25μ [H/m]
0.5

0.4

0.3

0.2

0.1

0.0
-15

-10

-5

0

5

10

15

H [A/m]Fig.4-7 The µ alteration under the field strength –12.5 < H < 12.5 H/m

μ [H/m]
0.5

0.4

0.3

0.2

0.1

0.0
-0.007-0.006-0.005-0.004-0.003-0.002-0.001

0.000

0.001

0.002

t [s]

Fig.4-8 The µ alteration with the 1/8 model magnet

26

Chapter 5
Conclusion

We discussed the scheme of induction acceleration to improve the characteristics of
REFER at Hiroshima University. We found that the loss energy 59.7 eV per turn due tosynchrotron radiation of the electron beam can be compensated by a troidal coil. We
estimated the magnetic core size and material together with the effect of the B-H
hysteresis curve.
We made 2 model magnets. The first one is made from ordinary steel that is 10 mmthick. The second one is a 1/8 model that has 1/8 cross section of the magnet to beinstalled. It is made from a stack of 30RG120 electromagnetic steel sheets of 0.3 mm
thickness.
The experiment with the 1/8 model magnet showed that the magnetic permeability
can be regarded as a constant µ ≈ 0.1 H/m under the field strength –12.5 < H < 12.5
A/m. It is a reasonable value for electromagnetic steel sheets.
On the other hand, the behavior of induced voltage from the ordinary iron core could
not be explained by an expected B-H curve. This suggests that some other effect, suchas the eddy current, should be taken into account.

27

Acknowledgements

First of all, the author expresses his special thanks to his supervisor Professor Osamu
Miyamura for his encouragement. A lot of help and continuous guidance by Professor
Ichita Endo, Dr Gennady L. Chakhalov, and Dr. Shinich Masuda are much appreciated.
We are grateful to the members of the Hadron Laboratory and the Photon Laboratory.
Special thanks are due to Dr. Junich Kishiro and Dr. Ken Takayama for their hospitality
and useful discussions at KEK. This work is financially supported by the
Venture-Business Laboratory of Hiroshima University.

28References[1]

JOHN J. LIVINGOOD Ph.D., “PRINCIPLES OF CYCLIC PARTICLEACCELERATORS”, D.VAN NOSTRND COMPANY,INC., pp. 257-259[2]

T. Ohkawa, Symposium on Nuclear Physics, Univ. of Tokyo, 1953, Suggestion ofreversed fields in alternate sectors.

[3]

Ken Takayama, HIGH ENERGY NEWS, Volume 19 Number 2 June/July 2000,
Japan Association of High Energy Physicists, pp. 58-69.

[4]

J. Kishiro et al, Proceedings of EPAC 2000, “RAPIDLY SEITCHEDACCELERATING DEVICES FOR INDUCTION SYSCHROTRON”.

[5]

K. Takayama et al, Proceedings of EPAC 2000, “KEK-PS UPGRADESCENARIO:

500MEV

ACCUMULATOR

AND

SUPER-BUNCHACCELERATION”.
[6]

K. Yoshida et al, “Commissioning of a Compact Synchrotron Radiation Source at
Hiroshima University”, APAC98, KEK, Tsukuba, Japan, 1998.

[7]“GIJYUTU KENTOU SHO” for REFER, TOSHIBA, 1996.

[8]

K. Itokawa, “Current monitor of REFER”, Graduation Thesis of the photon lab. atHiroshima University, 1998.

[9]

KAWATETSU HPDR CORE COTALOGUE 2000/3.

[10] HANDBOOK OF MAGNETIC ENGINEERING.
[11] “WE Control API Users Manual ver.3”, IM707741-61J, YOKOGAWA, 2000.
[12] “WE Control API ASCII Command Users Manual for PSI modules ver.1”,
IM707741-91J, YOKOGAWA, 1998.
[13] K. Tanaka and T. Tezuka, “Borland C++ Builder 3 Component Katsuyou Guide &Zissen Programming”, CUTT SYSTEM, 1998.

29

Appendix
A Software for Yokogawa DAC module

In Appendix we describe to make a control software of Yokogawa DAC module.
We use Borland C++ Builder 4 of the programming language.
As we use DLLs of Yokogawa control API, we send control ASCII command tomodule. The kinds of ASCII command refer to module manuals.
In this chapter the using way of DLLs and the converting way of Yokogawa giving
header file for Microsoft Visual C++ is shown.
We need to define the functions of the DLLs to use control command. For example
the command “WeInit” can be used by following programming.
Unit1.cpp//----------------------------------------------------------------------------------------------#include "WeAscii.h"#include "Unit1.h"//----------------------------------------------------------------------------------------------// Import DLL
hWeAscii = LoadLibrary("WeAscii10.dll");// Initialize DLL
WeInit = (ProcWeInit)GetProcAddress(hWeAscii,"WeInit");//----------------------------------------------------------------------------------------------WeInit(NULL,"ethernet",WE_CONTROLLER);//----------------------------------------------------------------------------------------------WeAscii.h (This is default setting file gave by Yokogawa)//----------------------------------------------------------------------------------------------unsigned short WINAPI WeInit( HWND hWnd, char* comm,unsigned short type );//-----------------------------------------------------------------------------------------------

30

Unit1.h//----------------------------------------------------------------------------------------------#include "WeAscii.h"//----------------------------------------------------------------------------------------------typedef unsigned short __stdcall (*ProcWeInit)( HWND hWnd,
char* comm, unsigned short type ) ;// Define DLL
ProcWeInit WeInit;//----------------------------------------------------------------------------------------------To use other command we define each command as same “WeInit”.
Above is all of program core part. Next we describe the important attentions which is
not written on the API manuals.
1.

All functions to send the ASCII commands include “WeAscii10.dll”. So, we
import it only.

2.

All functions are defined by the unsigned short type. In the manuals gave by
Yokoawa, functions are defined by int type. The latter is only visual BASIC. Be
careful !

3.

On C++ Builder Variant type is very complex. “WeSetControl”, and“WeGetControl” use the Variant type.

Example using Variant type;
Unit1.cpp//----------------------------------------------------------------------------------------------#include "WeAscii.h"#include "Unit1.h"//----------------------------------------------------------------------------------------------// Import DLL
hWeAscii = LoadLibrary("WeAscii10.dll");// Initialize DLL
WeSetControl = (ProcWeSetControl)GetProcAddress(hWeAscii,"WeSetControl");
WeGetControl = (ProcWeGetControl)GetProcAddress(hWeAscii,"WeGetControl");31

//----------------------------------------------------------------------------------------------AnsiString Setting = Edit1->Text;
WeSetControl(hMo75121,"CH1:Output",Variant((LPCTSTR)Setting.c_str()));
WeGetControl(hMo75121,"CH1:Output",&value);Memo1->Lines->Add("CH1:Output の値 "+ AnsiString(value));//----------------------------------------------------------------------------------------------WeAscii.h (This is default setting file gave by Yokogawa)//----------------------------------------------------------------------------------------------unsigned short WINAPI WeSetControl( HANDLE hMo,char* command, VARIANT var ) ;unsigned short WINAPI WeGetControl( HANDLE hMo,char* command, VARIANT* var ) ;//----------------------------------------------------------------------------------------------Unit1.h (This is important part)//----------------------------------------------------------------------------------------------#include "WeAscii.h"//----------------------------------------------------------------------------------------------typedef unsigned short __stdcall (*ProcWeSetControl)( HANDLE hMo,char* command, OleVariant var ) ;typedef unsigned short __stdcall (*ProcWeGetControl)( HANDLE hMo,char* command, Variant* var ) ;// Define DLL

ProcWeSetControl WeSetControl;
ProcWeGetControl WeGetControl;//-----------------------------------------------------------------------------------------------

32

Induction Acceleration for Beam-Orbit Control
Seiji Matsuno
Department of Physics, Faculty of Science, Hiroshima University

Copyright © 2000-2001 by Seiji Matsuno
Serial Number Online PDF version / 15