The 14th Symposium on Accelerator Science and Technology, Tsukuba, Japan, November 2003

THE TABLETOP SYNCHROTRON MIRRORCLE-6X
D. Hasegawa*, H. Yamada, A. I. Kleev, N. Toyosugi, T. Hayashi*,T. Yamada*, I. Tohyama*, and Y. D. Ro*
Ritsumeikan University, Synchrotron Light Life Science Centre
1-1-1 Nojihigashi, Kusatsu-City, Shiga 525-8577* on leave from Photon Production Lab. Ltd., 4-2-1 (808) TakagaiChoMinami,Omihachiman-city 523-0898, JAPANAbstract
The construction of the tabletop synchrotron
MIRRORCLE-6X is completed. The 6-MeV microtron
beam test and the injection to the synchrotron are inprogress. The electron beam current extracted from theMicrotron is reached 100 mA with 500 ns pulse durationand 400 Hz repetition rate. The measured main magnetic
field distribution of the synchrotron showed good
agreement with calculation, which promise 20 mm•mrad
acceptance.

The fabrication of the MIRRORCLE-6X is completed
at present through the physical designing by computer
simulations and mechanical designing. An overview of
the completed MIRRORCLE-6X is shown in Fig. 1. We
have started commissioning of the Microtron injector, andthe beam injection to the synchrotron in September.
In this paper, MIRRORCLE-6X specifications and thefeature of x-ray beam lines are given. Results of the beam

INTRODUCTION
Novel x-ray source based on a low energy tabletop
synchrotron has been proposed by Yamada [1,2] and isdemonstrated with its brilliant x-ray production by using
MIRRORCLE-20, which is a 20 MeV synchrotron having
15 cm orbit radius, and 1.2 m magnet OD [3]. For the xray production an inelastic collision of circulating
relativistic electrons with a tiny target placed in thecentral orbit is utilized. The observed brilliance of hard xrays is comparable to SR. This novel source is unique by
its few µm x-ray source size, which is determined bytarget size, by its high energy transfer rate, and by its
broadband x-ray spectrum of from few KeV up to theenergy of injected electron dominated by the hardcomponents.
Photon Production Lab. Ltd. [4] commercializes thisnovel source and develops even smaller synchrotron
MIRRORCLE-6X, which is the 6 MeV version
composing of the 60 cm OD magnet. The expectedbrilliance is order of 1011 photons, which will be the 1000
times more of MIRRORCLE-20. The total flux exceedsthat of conventional SR.
At the beginning MIRRORCLE-20 was developed forFIR lasing according to “Photon Storage Ring” (PhSR)
theory [5]. The PhSR required the space for placing a
concentric barrel-shaped optical resonator inside thechamber surrounding the electron orbit, so that the outer
diameter of the main magnet body became 1.2 m.
Moreover it was designed to storage 50 MeV electrons atmaximum in 15 cm orbit radius using a normal
conducting magnet. By decreasing the electron energy to6 MeV and aiming at only the x-ray generation, theMIRRORCLE-6X is designed to be the 60 cm outer
diameter and 28 cm height, which are the one half in thediameter and one quarter in the height of MIRRORCLE20.

Figure 1: An overview of the portablesynchrotron “MIRRORCLE-6X”.
test on the 6-MeV Microtron injector are shown. The 1/2integer resonance injection method utilized in theMIRRORCLE-6X is also explained.

MIRRORCLE-6X SPECIFICATIONSMIRRORCLE-6X specifications are listed in table 1.
The 6-MeV microtron is the type, which has a LaB6
electron emitter inside the single cell-accelerating cavity.
The electrons are extracted directory by the RF field.
Because of this scheme we are able to apply strong
magnetic field, which results in the 60 cm small out
diameter magnet. The RF source is a powerful pulse
klystron that utilizes multi-beam with 30 kV low anodevoltage. The output power is 5 MW at peak, 5 kW on
average, and 45 % efficiency with the 80 cm x 30 cm
compact body. Operating frequency is 2.45 GHz.
The synchrotron is made of one peace of cylindricalnormal conducting magnet of 60 cm OD. The 1/2-integer
resonance is selected to provide stronger vertical focusing
power compared with the 2/3-integer resonance used for

The 14th Symposium on Accelerator Science and Technology, Tsukuba, Japan, November 2003

MIRRORCLE-20, which is suitable to minimize thevertical x-ray source size. To introduce the 1/2-integer
resonance injection scheme the n-value of the magnet
field is set to 0.72 over 10 cm in radial direction aroundthe central orbit. The expected beam size is less than mmin vertical, and 10 mm in horizontal. The perturbator totrigger the 1/2-integer resonance is one-tern air coremagnet, which produces ±0.42 T•mm magnetic field at±30 mm from the central orbit.
The synchrotron accommodates three x-ray beam ports
as seen in Fig. 2 together with the beam dynamics. Eachport is assigned to X-ray crystallography, X-raymicroscope, X-ray fluorescent analysis, and X-rayimaging.
The X-ray microscopeandX-ray
crystallography beam line is equipped with a focusing
element made of multi-layered 8-set of cylindrical mirrors
aligned in concentric.
Table 1: MIRRORCLE-6X specifications

Figure 2: Injection trajectory on the median plane of
the MIRRORCLE-6X obtained by the computer
simulation is shown.

Figure 3: Phase plot of radial motion
showing the capture process.
orbiting electrons, the resonance injection method makes
a continuous beam injection possible. This is an essential
factor for the high brilliance x-ray production.

Injection trajectory

Resonance injection scheme
The resonance injection method is considered to be atime reversal of half integer resonance extraction. Its
method is similar to the super-conducting synchrotronAURORA [6,7,8], and is different from MIRRORCLE-20,
which uses the 2/3-integer resonance.
In resonance injection scheme, the perturbator (PB)
placed under the main magnetic field kicks the beamelectron toward outside from the central orbit andgradually changes its orbit to the central orbit. Phase plotof radial motion in the capture process is shown in Fig. 3.
The beams injected on or near the separatrix are trappedin the stable area after 20 turns by damping the PB field
in a synchronized way. Thus the PB dose not disturb theThe main magnetic field distribution of the synchrotron
was designed by the code TRIM. The computer
simulation of the injection trajectory was made by thecode DYNA to decide the position and angle of theinjection port. We found that the measured magnetic field
distribution is in good agreement with calculated one
around the central orbit as shown in Fig. 4. However, themeasured magnetic field around the fringe has somedeviation from the calculated one. To take into accountthe effect of the fringing field to the injection trajectory,
we have carried out the computer simulation by using themeasured magnetic fields. We found that the 6-MeVelectron beam can be injected from the designed injection
port to the synchrotron as shown in Fig. 2.
The injection of the electron beam to the synchrotron isin progress. According to the last two experiences of theexact circular ring, AURORA and MIRRORCLE, webelieve that the injection will be carried without problems
as theoretically predicted.

The 14th Symposium on Accelerator Science and Technology, Tsukuba, Japan, November 2003

MIRRORCLE-6X is 1000 times higher of MIRRORCLE20. In this project the back ground radiation from thecavity and the iron extraction channel is the important
subject to be minimized. We will minimize theseradiations dramatically by introducing electron-focusing
elements inside magnet for medical and industrial use ofthis machine.

CONCLUSION

Figure 4: Main magnet field distributions.

COMMISSIONING OF MICROTRON
Commissioning of the 6-MeV microtron injector started
on Sep. 20, 2003. At the first operation, the electron beam
current of 5 mA was recorded with the probe placed in thelast orbit. After by adjusting the cavity form, and byadjusting the median plane by changing slightly thecurrent of the upper and lower coil, as a result, theelectron beam current of more than 100 mA was extracted
from the microtron. We use iron extraction channel. Thepulse duration was 500ns as shown in Fig. 5. The fastcurrent transformer (BERGOZ Instrumentation FTC-08205:1) is used to measure the beam current. The emissionof 1300 mA from LaB6 single crystal is obtained byheating with accelerated electron beams from the filament
at 500V and 50mA. Accordingly the capture efficiency of
7.7 % is reached. The beam current of 100 mA with 400
Hz repetition rate guarantees that the X-ray brilliance ofFigure 5: The measured beam current (top)and emission current (bottom).

The construction of MIRRORCLE-6X, the world
smallest synchrotron was completed and the extraction of
100 mA from the classical microtron was achieved. The
injection of electron beam to the synchrotron is inprogress. The measured magnetic field distribution is ingood agreement with calculated one around the central
orbit. The 6-MeV electron beam should be injected
through the designed injection trajectory. We are quite
optimistic to this operation from the past experiences of
Aurora and MIRRORCLE-20.
The microtron capture efficiency of 7.7 % is not sohigh. We hope we are able to increase some more by finetuning.
In summarizing, MIRRORCLE-6X will provide
satisfactory x-ray flux for variety of applications. The
high brilliant x-ray beam generated by only 60 cm OD
synchrotron can be utilized on site in medical andindustrial applications, which will change the paradigm ofX-ray business.
The development and study of MIRRORCLE-6X aresupported by a Grant-in-Aid for Science Research fromJapan Society of the Promotion of Science.

REFERENCES[1] H. Yamada, Jpn. J. Appl. Phys. 35 (1996) L182.
[2] H. Yamada, Nucl. Instr. and Meth. A 467-468 (2001)
122.
[3] H. Yamada, Nucl. Instr. and Meth. B 199 (2003) 509516.
[4] MIRRORCLE 6X is commercially available from
Photon Production Laboratory Ltd.: 4-2-1(808)
TakagaiChoMinami, Omihachiman-city, SHIGA,523-0898, Japan
URL: http://www.photon-production .co.jp[5] H. Yamada, Adv. Colloid Interface Sci. 71-72 (1997)
371-392.
[6] T. Takayama, Nucl. Instr. and Meth. B 24-25 (1987)
420.
[7] H. Yamada, J. Vac. Sci. Technol. B 8 (6) (1990)
1628.
[8] N. Takahashi, Nucl. Instr. and Meth. B 24-25 (1987)
425.