核理研研究報告

第39巻

39 2006

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Preface
This issue of Research Report of Laboratory of Nuclear Science reports research activities of the
LNS performed in the 2005 academic/ﬁscal year (April 2005-March 2006). Major research activities are
based on the electron accelerator complex consisting of the 300-MeV LINAC and the 1.2-GeV STB ring.
The accelerators have altogether provided a beam time of about 2,200 hours for various experiments
through the year.
The (γ, η) and (γ, π0) measurements performed with the SCISSORS II spectrometer at the Gev- γ
experimental hall 2 are ﬁnished in this year, and a construction of a 4π spectrometer called FOREST
has been planned. In the experimental hall 2, a construction of a larger spectrometer called New NKS
spectrometer has started: A dipole magnet which was a main part of the cyclotron at the CyclotronRadio Isotope Center was brought in and placed on the gamma-ray beam line. In this occasion, thevacuum chamber of the STB Tagger 1 was improved to reduce materials for recoil electrons to passthrough. Experiments on coherent radiation were performed by using pulsed electron beams from the
LINAC. Various radioactive isotopes were produced by using high intensity beams below 50 MeV at theexperimental hall 1. They were served for element analyses as well as for detailed study of decay
properties.
We hope that this Report will serve as a quick overview of the present LNS activities over a varietyof nuclear research ﬁelds.

Jirohta KASAGI
Director

Research Report of Laboratory of Nuclear Science
Volume 39, 2006
Contents
Ⅰ．Nuclear Physics
Ⅰ－１

Study of Strangeness Photo-production in the Threshold Region at LNS-Tohoku

1Petr Bydvžovský, Mitsuhiko Ejima, Yuu Fujii, Kenta Futatsukawa, Osamu Hashimoto,
Kentarou Hirose, Takatsugu Ishikawa, Satoru Kameoka, Hiroki Kanda,
Fumiaki Kato, Sari Kinoshita, Tadashi Kinoshita, Takeshi Kon, Osamu Konno,
Kazushige Maeda, Akihiko Matsumura, Yuusuke Miura, Fusashi Miyahara,
Haruhisa Miyase, Tadashi Nakabayashi, Kenichi Nonaka, Atsushi Ohtani,
Yuichi Okayasu, Masamichi Oyamada, Atsushi Sasaki, Hajime Shimizu,
Tadaaki Tamae, Hirohito Yamazaki, Atsushi Sasaki, and Osamu Konno
Ⅰ－２

Double Pion Photoproduction on Deuteron

7

Kentarou Hirose, Mitsuhiko Ejima, Takeji Fujibayashi, Yuu Fujii,
Kenta Futatsukawa, Osamu Hashimoto, Takatsugu Ishikawa, Satoru Kameoka,
Hiroki Kanda, Fumiaki Kato, Sari Kinoshita, Tadashi Kinoshita, Takashi Kon,
Osamu Konno, Kazushige Maeda, Akihiko Matsumura, Yusuke Miura,
Fusashi Miyahara, Haruhisa Miyase, Tadashi Nakabayashi, Satoshi Nue Nakamura,
Hiroshi Nomura, Atsushi Ohtani, Yuichi Okayasu, Masamichi Oyamada,Atsushi Sasaki, Hajime Shimizu, Kyo Tsukada, Toshiyuki Takahashi,
Tadaaki Tamae, Hirokazu Tamura, Tatsuo Terasawa, Hiroaki Tsubota,
Daisuke Uchida, Mifuyu Ukai, Hirokazu Yamauchi, Hirohito Yamazaki,
Keisuke Yawata, Masaki Wakamatsu, and Takaomi Watanabe
Ⅰ－３

Study of Giant Resonances in the 24Mg(e, e' α) Reaction

21

Kazunori Takahashi, Kazufumi Abe, Ryo Hashimoto, Yukie Hayashi,
Kentaro Hirose, Takatsugu Ishikawa, Hiroki Kanda, Kazushige Maeda,
Haruhisa Miyase, Itaru Nishikawa, Yoshiyuki Sato, Tadaaki Tamae,
Hiroaki Tsubota, Mitsuru Utoyama, Masaki Wakamatsu,
Masayoshi Watabe, and Yoshimi Yamaguchi
Ⅰ－４

Status Report of Neutral Kaon Photo-production Study using Neutral Kaon Spectrometer2 (NKS2) at LNS-Tohoku
Nobuyuki Chiga, Takeshi Fujibayashi, Yu Fujii, Kenta Futatsukawa,
Osamu Hashimoto, Kentarou Hirose, Takatsugu Ishikawa, Hiroki Kanda,
Masashi Kaneta, Daisuke Kawama, Osamu Konno, Yue Ma, Kazushige Maeda,
Nayuta Maruyama, Akihiko Matsumura, Masaki Matsuzawa, Youhei Miyagi,
Haruhisa Miyase, Tadashi Nakabayashi, Satoshi Nue Nakamura,

31

Kenichi Nonaka, Yuichi Okayasu, Atsushi Sasaki, Hajime Shimizu,
Koutarou Shirotori, Koutaku Suzuki, Tadaaki Tamae, Hirokazu Tamura,
Kyo Tsukada, and Hirohito Yamazaki
Ⅰ－５

Construction of a Forward Electro-magnetic Calorimeter SCISSORS Ⅲ

35

Takatsugu Ishikawa, Hiroshi Fukasawa, Ryo Hashimoto, Takashi Ishida,
Jirohta Kasagi, Syuzou Kuwasaki, Fusashi Miyahara, Keichi Mochizuki,
Tadashi Nakabayashi, Kenichi Nawa, Yasuyuki Okada, Kenyu Okamura,
Yoshihito Onodera, Yutaka Saitoh, Hajime Shimizu, Koutaku Suzuki,
Hirohito Yamazaki, and Hiroki Yonemura
Ⅰ－６

Installation of a Dipole Electromagnet RTAGX

39

Takatsugu Ishikawa, Ryo Hashimoto, Takashi Ishida, Jirohta Kasagi,
Syuzou Kuwasaki, Fusashi Miyahara, Kazushige Maeda, Keichi Mochizuki,
Kenichi Nawa, Yasuyuki Okada, Yoshihito Onodera, Hajime Shimizu,
Koutaku Suzuki, and Hirohito Yamazaki

Ⅱ．RadiochemistryⅡ－１

Photoactivation Analysis of Potassium in High Purity Gadolinium Oxides

43

Yasuji Oura, Ai Sasaki, and Mitsuru Ebihara
Ⅱ－２

Separation Methods of Radioactive Carbon from Concrete Samples by Thermal
Combustion Methods

47

Yuichi Izumi, Yoshiaki Ando, Kazuhiro Matsumura, Tsutomu Ohtsuki,
Hideyuki Yuki, and Kazuyoshi Masumoto

Ⅲ．Accelerator, Synchrotron Radiation, and Instrumentation
Ⅲ－１

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅰ

55

Yukio Shibata, Kimihiro Ishi, Tsutomu Tsutaya, Noriaki Horiuchi,
Yusaburo Segawa, Yasuhiro Kondo, Hiroshi Miyazaki, Fujio Hinode,
Tetsuyuki Ochiai, and Kazuo Ohtaka
Ⅲ－２

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅱ

67

Yukio Shibata, Kimihiro Ishi, Tsutomu Tsutaya, Noriaki Horiuchi,
Yusaburo Segawa, Yasuhiro Kondo, Hiroshi Miyazaki, Fujio Hinode,
Tetsuyuki Ochiai, and Kazuo Ohtaka
Ⅲ－３

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅲ
Yukio Shibata, Kimihiro Ishi, Tsutomu Tsutaya, Noriaki Horiuchi,
Yusaburo Segawa, Yasuhiro Kondo, Hiroshi Miyazaki, and Fujio Hinode

81

Ⅲ－４

New Radiation Control System for Personal Permission, Status and Record

85

Yoshonobu Shibasaki, yumi Sugawara, Hideyuki Yuki, Hirohito Yamazaki, andTsutomu Ohtsuki

Ⅳ．List of Publication
95

Ⅴ．Approved Experiments
Ⅴ－１

Former Term in 2005

99

Ⅴ－２

Latter Term in 2005100

核理研研究報告

第39巻

目

次

Ⅰ．原子核物理
Ⅰ－１

Study of Strangeness Photo-production in the Threshold Region at LNS-Tohoku
Petr Bydvžovský，江島光彦，藤井石川貴嗣，亀岡優，二ツ川健太，橋本覚，神田浩樹，加藤文章，木下沙理，木下治，廣瀬健太郎，
忠，近

岳志，

今野

収，前田 和茂，松村彰彦，三浦勇介，宮原房史，宮瀬晴久，中林

中村

哲，野村

清水

肇，高橋俊行，玉江忠明，田村裕和，寺沢辰生，坪田 博明，塚田洋，野中健一，大谷

1

匡，

篤，岡安雄一，小山田正学，佐々木厚，暁，

鵜養美冬，内田大介，山内大和，山崎寛仁，八幡啓介，若松正樹，渡辺崇臣
Ⅰ－２

Double Pion Photoproduction on Deuteron7

廣瀬健太郎，江島光彦，藤林丈司，藤井 優，二ツ川健太，橋本亀岡 覚，神田浩樹，加藤文章，木下沙理，木下

忠，近

岳志，今野

前田和茂，松村彰彦，三浦勇介，宮原房史，宮瀬晴久，中林
野村

洋，大谷

治，石川貴嗣，匡，中村篤，岡安雄一，小山田 正学，佐々木厚，清水

收，
哲，

肇，塚田

暁，

高橋俊行，玉江忠明，田村裕和，寺沢辰生，坪田博明，内田大介，鵜養美冬，
山内大和，山崎寛仁，八幡啓介，若松正樹，渡辺崇臣
Ⅰ－３

Study of Giant Resonances in the 24Mg(e,e' α) Reaction
高橋一憲，阿部和史，橋本21亮，林由紀江，廣瀬健太郎，石川貴嗣，神田浩樹，

前田和茂，宮瀬晴久，西川 至，佐藤祥幸，玉江忠明，坪田博明，宇藤山満，
若松正樹，渡部政義，山崎寛仁
Ⅰ－４

Status Report of Neutral Kaon Photo-production Study using Neutral Kaon Spectrometer2 (NKS2) at LNS-Tohoku

31

千賀信幸，藤林丈司，藤井優，二ツ川健太，橋本神田浩樹，金田雅司，川間大介，今野収，馬越，前田和茂，丸山那由太，

松村彰彦，松澤正樹，宮城要平，宮瀬晴久，中林
岡安雄一，佐々木厚，清水田村裕和，塚田Ⅰ－５匡，中村哲，野中健一，肇，白鳥昂太郎，鈴木耕拓，玉江忠明，暁，山崎寛仁Construction of a Forward Electro-magnetic Calorimeter SCISSORS Ⅲ
石川貴嗣，深澤宏司，橋本

Ⅰ－６治，廣瀬健太郎，石川貴嗣，亮，石田孝司，笠木治郎太，鍬崎秀三，宮原房史，

望月恵一，中林匡，縄齋藤雄高，清水肇，鈴木耕拓，山崎寛仁，米村博樹

健一，岡田康友紀，岡村憲有，小野寺義人，

Installation of a Dipole Electromagnet RTAGX
石川貴嗣，橋本望月恵一，縄35

39

亮，石田孝司，笠木治郎太，鍬崎秀三，宮原房史，前田和茂，健一，岡田康友紀，小野寺義人，清水肇，鈴木耕拓，山崎寛仁

Ⅱ．放射化学Ⅱ－１

高純度酸化ガドリニウム試薬中のカリウムの光量子放射化分析

43

大浦泰嗣，佐々木愛，海老原充
Ⅱ－２

加熱回収法によるコンクリート試料中放射性炭素分離法の検討
泉雄一，安藤佳明，松村一博，大槻47

勤，結城秀行，桝本和義

Ⅲ．加速器・放射光・測定装置
Ⅲ－１

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅰ
柴田行男，伊師君弘，蔦谷

55
勉，堀内典明，瀬川勇三郎，近藤泰洋，宮嵜博司，日出富士雄，落合哲行，大高一雄
Ⅲ－２

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅱ
柴田行男，伊師君弘，蔦谷

67
勉，堀内典明，瀬川勇三郎，近藤泰洋，宮嵜博司，日出富士雄，落合哲行，大高一雄
Ⅲ－３

Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter
Wave Region. Ⅲ
柴田行男，伊師君弘，蔦谷

81
勉，堀内典明，瀬川勇三郎，近藤泰洋，宮嵜博司，日出富士雄
Ⅲ－４85

新しい管理区域入退管理システム
柴崎義信、菅原由美、結城秀行、山崎寛仁、大槻勤

Ⅳ．論文リスト
95

Ⅴ．課題採択結果
Ⅴ－１

平成17年度前期

99

Ⅴ－２

平成17年度後期

100

Ⅰ．Nuclear Physics

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

1(LNS Experiment : #2446, #2506)

Study of Strangeness Photo-production in theThreshold Region at LNS-Tohoku
P. Bydžovský1, M. Ejima2, Y. Fujii2, K. Futatsukawa2, O. Hashimoto2, K. Hirose2,
T. Ishikawa3, S. Kameoka2, H. Kanda2, F. Kato2, S. Kinoshita2, T. Kinoshita3,
T. Kon2, O. Konno4, K. Maeda2, A. Matsumura2, Y. Miura2, H. Miyahara3, H. Miyase2,
T. Nakabayashi3, K. Nonaka2, A. Ohtani2, Y. Okayasu2, M. Oyamada2, A. Sasaki5,
H. Shimizu3, T. Takahashi3, T. Tamae3, H. Tamura2, T. Terasawa3, H. Tsubota2,
K. Tsukada2, S.N. Nakamura2, H. Nomura2, M. Ukai2, D. Uchida2, H. Yamauchi2,
H. Yamazaki3, K. Yawata2, M. Wakamatsu2, T. Watanabe
1

Nuclear Physics Institute, 25068, Res Czech Repubic

2

3

Department of Physics, Tohoku University, Sendai, 980-8578
Laboratory of Nuclear Science, Tohoku University, Sendai, 982-0826
4

Department of Electrical Engineering, Ichinoseki National
College of Technology, OIchinoseki, Iwate 010-8502
5Department of Electrical and Electronic Engineering, Akita University, Akita, 010-8502§1. Introduction
The investigation of the kaon production on a nucleon by the electromagnetic interaction provides
invaluable information on the strangeness production mechanism, strength of meson-baryon coupling
constants and structure of hadrons, being labeled by the strangeness degree of freedom. Such studies
using beams of real photons and electrons have been conducted both experimentally and theoreticallysince the 1950's, taking advantage of the electromagnetic interaction that is understood better than the
hadronic interaction. Until now, the experimental studies have been carried out in p(γ, K＋)Λ, p(γ, K＋)Σ0
and p( γ, K0) Σ＋ reactions among six isospin channels [1, 2]. However, no data have been measured forthe other three channels on a neutron. Theoretically, phenomenological models have been constructedbased on measured channels so far. The isobar models, Kaon-MAID [3] and SLA [4], were adopted in
the present analysis. The predictions of the photon energy dependence and the kaon angular
distribution of the other three channels on a neutron using these models are quite different.
The lack of the key data for strangeness photoproduction of the three channels on a neutron is dueto the experimental difficulties to measure neutral kaons and to prepare a neutron target. The
measurement of these three strangeness production channels provides much information on thestrangeness photoproduction mechanism. In particular, the n( γ, K ＋ ) Λreaction has following features:(1) Since no charge is involved, the t-channel Born term does not contribute.
(2) It is a mirror reaction to p( γ, K ＋ ) Λ.
For the hyperon resonance exchange terms, a coupling constant, g KΣN, changes its sign from theisospin symmetry, g K 0 Σ0 n = － g K 0 Σ0 p, resulting the different interference effect. Furthermore, the number

2of resonances to be considered is small in the threshold region. Therefore, the n(γ, K0)Λ reaction is
expected to play an essential role to investigate the strangeness photoproduction mechanism.
In this report, we present the results of photoproduction of neutral kaons on deuterons near thethreshold. The resutls from a carbon target are described in Ref. [4].

§2. Experiment
We carried out the experiment of the d ( γ, K0) reaction in the threshold region, Eγ = 0.8 ~ 1.1 GeV.
The K 0s were measured in π＋π－ decay mode with Neutral Kaon Spectrometer (NKS), which we installedin LNS-Tohoku. Figure 1 shows a schematic view of NKS which consists of a dipole magnet of 107 cm
diameter and 60 cm gap with 0.5 T, straw drift chambers (SDC), cylindrical drift chambers (CDC), innerhodoscope (IH), outer hodoscope (OH) and electron veto counters (EV). The detector conﬁguration wassymmetric against the beam line. The solid angle of NKS was about πsr. The CDC and SDC were used
to measure particle momenta in the horizontal plane by trajectory reconstruction. The magnetic ﬁeld
map was calculated by TOSCA. IH and OH were used for the time-of-ﬂight measurement and event
triggers. The momenta and time-of-flights were used for the particle identification. As a trigger
condition, we required more than two charged particles; at least one event both in the left and rightarms in coincidence with a tagger signal. EVs were employed to reduce the serious backgroundtriggered by γ→ e ＋ e － conversion. They covered vertically ± 2.5 cm in the horizontal plane at OH's
positions. The geometrical acceptance was reduced by 8%.
The photon beam was generated from the 1.2 GeV electron beam via bremsstrahlung and its energy
was tagged by the STB-tagger system [6]. The typical tagged photon intensity was 2 × 106 /sec and thetagging efﬁciency was 79 ± 1 %.
In order to investigate the K 0 quasi-free and elementary production process on a neutron, we useda natural carbon target and a liquid deuterium target. The thickness of both targets are 2.1 g/cm2 forcarbon and 0.54 g/cm2 for deuterium. The liquid deuterium target system was developed for thisexperiment and provided the stable liquid-state deuterium during the experimental period [7].

§3. Analysis
The momenta of particles were derived from the curvature of trajectories. Besides, the velocities ofparticles were calculated from the time of ﬂight and the ﬂight length. The e ＋ e － events were removed byrejecting the events of which the vertex position was upstream the target. Figure 2(a) shows the vertex
point distribution of the π＋π－ events. An opening angle ( η) cut of － 0.9 ＜ cos η ＜ 0.8 was applied inorder to remove the e ＋ e － or vertex mis-reconstruction events. The vertex resolution was estimated tobe 1.3 mm in RMS in the beam direction. Most of events were originated in the target. Backgrounds
through such as a multi-pion productions, N* and ρ, whose production cross sections are much larger
than that of kaon production. Hence, no peak is observed in the invariant mass spectrum as shown in
Fig.2(b) for events in the target region. K 0 events are enhanced by selecting vertex points in the decay
volume, because K S0 has a relatively long life time of cτ= 2.68 cm. Figure 2(c) shows the invariant mass
spectrum when events in the decay volume are chosen. The peak of K S0 is clearly seen as shown in the

3ﬁgure. Number of K 0 events is about 900 in the present data.
＿
In order to obtain the cross section, we deﬁned the gate in the invariant mass spectrum, 0.46 ＜M(π π )＜0.54 GeV/c2. Momentum distributions of K0 were obtained after subtracting background contributions.
＋ －The origin of the backgrounds were considered as (1) leakage from the target region due to the ﬁnite
resolution of the vertex point reconstruction, and (2) wrong combination between π＋ from K 0 and π－from Λ . The ﬁrst one was estimated from the events originated in the target region, and the second one
was estimated by a Geant4 simulation. These estimations gave the shape of the backgrounds, and themagnitude of the backgrounds were adjusted by ﬁtting the invariant mass spectrum. Figure 3 shows
the ﬁtting result assuming a gaussian for K 0 and the shapes of backgrounds as estimated in the photon
energy from 0.9 to 1.0 GeV (E low) and form 1.0 to 1.1 GeV (E high).
The acceptance of NKS was calculated by a Geant4 simulation. The geometry of NKS was

Fig.1. Schematic view of the Neutral Kaon Spectrometer (NKS).

Fig.2. (a) Vertex distribution for π＋π－ events. The beam comes from left to right. Events
come mainly from the target region.(b) and (c) An invariant mass spectrum of
π＋π－ events with the gate that the vertex is in the target for (b) and outside
the target denoted by decay volume for (c).

4

Fitting results of invariant mass spectra in the photon regions from 0.9 to 1.0
GeV (Elow, left) and from 1.0 to 1.1 GeV (Ehigh, right). The contribution around 0.4
GeV/c2 comes from the wrong combination background and that around 0.6
GeV/c2 comes from the leakage of the target events. The peak near 0.3 GeV/c2
comes from the e ＋ e － events.

Fig.3.

considered realistically, and the position and time resolution of the detectors were taken into account.
Various analysis efﬁciencies were also estimated in the acceptance.

§4. Results and Discussion
The obtained momentum spectra of K 0s are shown in Fig. 4. The backgrounds contributions are
already subtracted. The integrated momentum range is limited as mentioned in the previous section.
The obtained spectra are compared with the calculations using the representative two models, KaonMAID [3] and Saclay-Lyon A (SLA) [4]. The lines represent calculations in the plane wave impulse
approximation framework using Bonn OBEPQ (One-Boson-Exchange-Potential in Q-space) deuteronwave function [8] by Bydžovský et al. [9]. The Kaon-MAID model is the only model to predict theelementary cross section of K 0 photoproduction on a neutron assuming SU(3) symmetry. On the other
hand, SLA has an adjustable parameter for K 0Λ photoproduction, since the ratio of the decay width between
the charged and neutral K 1 resonance (rK Kγ) is unknown. In Kaon-MAID, this ratio was obtained from1the γ ＋ p → K ＋Σ process. Therefore, the elementary cross sections of SLA are calculated assuming
0＋

various rK K γ . Kinematical regions are also selected for the calculations similarly to the experimental
1

data.
Since we measured only K 0, the Σ production process may contribute in addition to K 0Λ production.
From the estimation using Kaon-MAID, the contributions of Σ production are negligibly small in the
Elow region and sizable large at lower momentum in the Ehigh region. The prediction based on the KaonMAID model is consistent with our data in the Elow region but too large in the Ehigh region even if the Σcontribution is involved. The spectra calculated by SLA with rK Kγ ＝ － 1.9 well account for the present
1

results at both energy regions.

5

Momentum dependences after the correction for efﬁciencies and subtraction of
backgrounds. The lines represent the calculations using Kaon-MAID (solid),
SLA( rK Kγ = －1.8, dotted), SLA( rK Kγ = －1.9, dashed), and SLA( rK Kγ = －2.0, dotdashed), The photon energy ranges are from 0.9 to 1.0 GeV (Elow, left) and from
1.0 to 1.1 GeV (Ehigh, right). The error bars are statistical, and systematic erros
are shown by kinked lines around data points.

Fig.4.

1

1

1

In the Elow region, the shape of the momentum spectrum in the laboratory system mainly depends
on the angular distribution in the center of mass system. From the momentum distributions using SLA
with various rK Kγ values, it is favored that the K 0 photoproduction on a neutron has a backward peak in1

the center of mass system.

§5. Summary
We have successfully measured neutral kaons, bombarding a liquid deuterium target with a photon
beam in the threshold region from 0.8 to 1.1 GeV . It was the ﬁrst data for K 0 photoproduction on the
deuteron in this energy region. The momentum spectra of K 0 production were compared with theoretical
spectra calculated assuming isobar models for the elementary process and a realistic deuteron wave
function for the target The present experiment has demonstrated a usefulness of the neutral kaon
measurement for the investigation of photo strangeness production reactions.

Acknowledgments
This work was supported by Grant-In-Aid for Scientiﬁc Research from The Ministry of Education ofJapan, Nos. 09304028, 12002001, 14740150 and 16GS0201.

References[1]

D.S. Carman et al.: Phys. Rev. Lett. 90 (2003) 131804.

[2]

R.G.T. Zegers et al.: Phys. Rev. Lett. 91 (2003) 1092001.

[3]

F.X. Lee, T. Mart, C. Bennhold, and L.E. Wright: Nucl. Phys. A695 (2001) 237.

[4]

T. Mizutani, C. Fayard, G.H. Lamot, and B. Saghai: Phys. Rev. C58 (1998) 75.

[5]T. Watanabe et al.: nucl-ex/0607022 (2006), submitted to Phys. Lett. B.

6[6]

H. Yamazaki et al.: Nucl. Instr. and Meth. A536 (2005) 70.

[7]

H. Kanda et al.: Research Report of LNS, Tohoku University 37 (2004) 27.

[8]

R. Machleidt, K. Holinde, and C. Elster: Phys. Rep. 149 (1987) 1.

[9]

P. Bydzovsky, M. Sotona, O. Hashimoto, and T. Takahashi: private communications (2004).

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

7(LNS Experiment : #2464, #2551)

Double Pion Photoproduction on Deuteron
K. Hirose1,＊ , M. Ejima1, T. Fujibayashi1, Y. Fujii1,
K. Futatsukawa1, O. Hashimoto1, T. Ishikawa2, S. Kameoka1,
H. Kanda1, F. Kato1, S. Kinoshita1, T. Kinoshita2,
T. Kon1, O. Konno4, K. Maeda1, A. Matsumura1, Y. Miura1,
F. Miyahara2, H. Miyase1, T. Nakabayashi2, S.N. Nakamura1,
H. Nomura1, A. Ohtani1, Y. Okayasu1, M. Oyamada1,
A. Sasaki3, H. Shimizu2, K. Tsukada1, T. Takahashi1,†,
T. Tamae2, H. Tamura1, T. Terasawa2, H. Tsubota1,
D. Uchida1, M. Ukai1,§, H. Yamauchi1, H. Yamazaki2,
K. Yawata1, M. Wakamatsu1, T. Watanabe1,‡
1

Department of Physics, Tohoku University, Sendai, 980-8578

2

3

Laboratory of Nuclear Science, Tohoku University, Sendai, 982-0826
Department of Electrical and Electronic Engineering, Akita University, Akita, 010-8502
4

Department of Electrical Engineering, Ichinoseki National College of Technology,
Ichinoseki, 021-8511

Exclusive cross sections for double-pion photoproductions on proton and deuteron were measured
in an energy range from 0.8 to 1.1 GeV using tagged photons at Laboratory of Nuclear Science, Tohoku
University. We employed the Neutral Kaon Spectrometer (NKS) to detect two pions in the ﬁnal state,
and deduced the cross section for the π＋π－ photoproduction on the "free" and "bound" proton. We havediscriminated between the quasi-free and non-quasi-free process applying the kinematical cut on the
missing momentum. We found that the total cross section for the γ"p" → pπ＋π－ reaction was about 60%of that for the "free" proton, and this is consistent with the previously obtained data. The one of thedominant part of the non-quasi-free process was found to be the double Δ production. Its cross section issmaller than the previous investigations.

§1. Introduction
In the pion photoproductions above the second resonance region, the doublepion emissions in theﬁnal state become important with increasing the photon energy. Recently, data for the multi-particle＊

Present address : Laboratory of Nuclear Science, Tohoku University, Sendai, 982-0826†

Present address : Institute of Particle and Nuclear Studies, High Energy Accelerator Organization(KEK), Tukuba, 305-0801§

Present address : Cyclotron and Radioisotope Center, Tohoku University, Sendai, 980-8678‡

Present address : Gifu University, Gifu, 501-1193

8detection are carried out using not only bubble chambers [1-4] but also large acceptance spectrometers
using tagged photon beams.
Since large acceptance photon spectrometers became available, the compilation of the exclusive
pion photoproduction data have proceeded including the neutral pion photoproductions [5, 6].
Measurements of double pion phtoproduction using a deuterium target have been also done. The
deuteron is often used as a neutron target under the assumption of the quasi-free (QF) process.
One of the result from these studies is that a large isospin dependence is not found in double pion
photoproduction on the nucleon. This is thought to be valid considering that the photoabsorption dataapproximately satisfy the following relation [7-9],σ (γd→ X )2 σ(γp→ X ).

敢

In the case of nuclear targets, the non quasi-free (NQF) process caused by the meson exchange current,
the delta current and the ﬁnal state interaction must be exclusively identiﬁed to select the QF channel.
The contribution of the NQF process was studied in the γd → pnπ＋π－ reaction [10]. The result of this study
is that the total cross section for π＋π－ photoproduction on the “bound” proton is the same as that on the“free” proton within the statistical uncertainties, but the contribution of the NQF process is not
negligible.
There are also data on the total cross section for the γn→ nπ＋π－ reaction which were measured using thedeuterium bubble chamber [3, 4]. The comparison between the total cross section for π＋π－ photoproduction
on the "bound" proton and that on the "bound" neutron has been done. Consequently, it is found thatthese values are the same within the statistical uncertainties, but they are smaller than that of “free”
proton,σ ( "p "→ pπ＋π－ )σ (γ"n"→ n π＋π－ ) < σ (γp → pπ＋π－ ),柑

where "p " and "n" denote the “bound” proton and “bound” neutron, respectively. If the cross sections forthe “bound” nucleon are the same as those for the “free” nucleon and there is a large contribution of the
NQF process, this seems to contradict the result of the photoabsorption data (Eq. 敢 ).
The NQF process has not been studied in detail. Many body effects seem to appear, even though thedeuteron is the simplest nuclei. We have measured double pion photoproduction on the proton anddeuteron in order to investigate the NQF process in detail. The aims of this study are :● To measure the total cross sections for π＋π－ photoproduction on the "free" and "bound" proton.
● To investigate the contribution of the NQF process and Δ ＋＋Δ － production in the γd→ p nπ＋π－
reaction.
In this article, we describe the results of the double pion photoproduction on the proton and thedeuteron to study the contributions of the NQF process.

9§2. Experimental Procedure
The experiments were carried out using an internal photon tagging system and a magnetic
spectrometer at Laboratory of Nuclear Science, Tohoku University.
2.1 Tagged photon beam
Electrons from the linear accelerator were injected into the Stretcher-Booster (STB) ring andaccelerated up to 1.2 GeV. Bremsstrahlung photons were produced by the internal photon tagging
system (STB-Tagger) [11]. It consists of a bremsstrahlung radiator, a bending magnet and a tagging
hodoscope. A carbon ﬁber of 11 μmφ was used for the radiator. It was inserted into the electron orbit bysynchronizing the storage-phase of the STB ring. The momenta of the recoil electrons were analyzed in
the magnetic ﬁeld of the bending magnet of the STB ring. The tagging hodoscope consists of 48 ﬁnger
counters and 12 backup counters. It covers the photon energy range from 0.8 to 1.1 GeV. The energy
span of each finger counter was about 6 MeV. The tagging rate was 2 ～ 3 MHz, and the tagging
efﬁciency was 74 ～83% in the whole tagging range. The photon beam impinged on the target through alead collimator, 300-mm long and 10 mm in diameter, placed 3.8 m downstream of the bremsstrahlung
radiator.
2.2 Target
A cryogenic system was used for liquid hydrogen and deuterium targets. The target container wasa cylinder of 50 mmφ and 30-mm length. It was located in the center of the spectrometer with its axis
parallel to the beam line.
The cylinder was made of 1-mm thick aluminum frame with windows of 75-μm thick Upilex-S
ﬁlm [12] adhered on the both ends. A CFRP (carbon ﬁber reinforced plastic) chamber was employed forthe vacuum insulation around the target. We also provided a beam window with the vacuum chamber.
The pressure and temperature of the target were monitored throughout the experiment. The
temperature was automatically controlled and kept at 14.5 K and 19.1K, which correspond to thethickness of 254 mg/cm2 and 571 mg/cm2 for the hydrogen and deuterium target, respectively.
2.3 Spectrometer
The Neutral Kaon Spectrometer (NKS) was used for the detection of charged particles. It consistsof two sets of drift chambers in the magnetic field, inner and outer hodoscopes, and electron vetocounters.
2.3.1 Analyzer magnet
The dipole magnet had a 60-cm pole gap and a 107 cmφ circular pole face with a nominal ﬁeld
strength of 0.5 T. The distribution of the magnetic ﬁeld was calculated by the TOSCA code [13] andscaled to the value measured at the center of the magnet. The non-uniformity was taken into account in
the off-line data analysis.

10
2.3.2 Hodoscopes
Two sets of scintillation hodoscopes, inner (IH) and outer hodoscope (OH), were employed to give
triggering signals to the online data acquisition system and to measure the time-of-flight (TOF) of
charged particles. Each IH was made of six plastic scintillator elements of 20 ~ 25-mm width, 120-mm
height and 5-mm thickness. As shown in Fig.1, they were located 60 mm away from the pole axis andsurround the target. Since IHs were within the magnetic ﬁeld, optical-ﬁber bundles were used to guide
scintillation photons to photo-multiplier tubes (PMTs) placed away from the magnetic ﬁeld. The OHs
were made of 34 plastic scintillator elements of 130 ~ 170-mm width, 600-mm length and 10-mm

Fig.1.

(a) Top view of the Neutral Kaon Spectrometer (NKS). It consists of a dipole magnet,
hodoscopes (IH, OH), drift chambers (SDC, CDC) and veto counters. (b) Closeup of thecenter of the NKS. The target is located inside of the IH.

thickness. The hit position of the charged particle was determined by the time difference between two
PMTs attached to the both ends of each scintillator. The typical TOF resolution was 0.5 ns.
2.3.3 Drift chambers
We employed two sets of drift chambers for the track and vertex reconstruction. Each set of thedrift chamber consists of a straw type cylindrical drift chamber (SDC) and a honeycomb type one (CDC).
They were located just around the IHs (Fig. 1). They covered an angular range from 15° to 165°on theboth sides of the beam line. Each SDC contains 78 gold-plated tungsten wires of 20 μmφ for drift-time
readout. The straws made of 180-μm thick aluminized Mylar ﬁlm were used for ﬁeld shaping. Each
CDC contains 402 gold-plated tungsten wires of 30 μmφ for drift-time readout and 1094 molybdenum
wires of 100 μmφ for field shaping. All wires were strung vertically and arranged in 16 concentric
layers. Mixture of 50% Ar and 50% C2H6 was used for the drift gas.

11
2.3.4 Veto counters
In order to reduce the e＋e－ background along the beam line, the electron veto counters (EV) were
employed. Each was made of a plastic scintillator of 1050 to 1250-mm length, 50-mm width and 5-mm
thickness. The EVs were placed at the mid plane of the NKS magnetic ﬁeld.
2.4 Data acquisition
The trigger condition required that there were at least two charged particles detected incoincidence on opposite sides of the beam line. The coincident signal of the left-, right-arm triggers andof the tagger signal was used as the trigger signal,[TRIGGER] ＝ ([TAG] [IH])[LEFT][RIGHT][VETO] .

桓

The [TAG] is the sum signal of tagging counters, and [IH] is the coincident signal between leftand right-side IH. The [LEFT] is the left-arm trigger deﬁned as a coincident signal of left-side IH andOH without any hit of the EV. The trigger serves as the gate signal for ADCs and as the start signal for
TDCs. Signals of the tagger, IH, OH and the EV were converted using the TKO modules. The CAMAC
TDCs were used for drift chamber signals.

§3. Data analysis
3.1 Particle identification
The trajectory of a charged particle reconstructed by the SDC ＋ CDC drift chamber systemdetermines the horizontal momentum p h and horizontal flight length l h. A spline-fit method was
employed for the reconstruction [14]. The time difference between two signals from the PMTs attachedto the top and bottom of the OH gives the vertical ﬂight length lν. The TOF t is given from the timedifference between the IH and OH signals. The velocity β and the momentum of the charged particle p+

Momentum (GeV/c)

1.0

p

0.5
0.0
-0.5
-

-1.0
0

1

2

3

4

5

6

7

Fig.2. The β-1 vs. momentum of charged particles. Negatively charged particles are located in thenegative signed momentum region.

12
are calculated by√ ( ).

lv
l2h ＋ l2v
， p ＝ ph １－ l
β＝ √
h
ct

2

棺

The particle mass is given by
m＝

p
1
)
(
(
c
β
√ －１） .
2

款2

Figure 2 shows an example of the two-dimensional plot, where the abscissa and ordinate mean the β-1
and momentum, respectively. Solid lines indicate the masses of protons and charged pions. The proton
contamination in the π＋ region and the π＋ contamination in the proton region are estimated to be lessthan 1.4% and less than 0.8%, respectively.
3.2 Vertex distribution
The vertex for the two-track events (V2track) is deﬁned as a point at which the distance between two
tracks becomes minimum. Three V2tracks are found in the three-track events. As shown in Fig.3 (a), we
6

Vertex for 2 tracks event

CFRP

4

Y(cm)

2
0
-2

Vertex for 3 tracks event

target container
-4
-6
-6

-4

-2

(a)
Fig.3.

0

X(cm)

2

4

6

(b)

(a) A schematic drawing of the vertex deﬁnition for the three-track events. (b) The vertex
distribution of three-track events.

determined the vertex for the three-track events V 3track as the center of the inscribed circle in thetriangle constructed by three V2tracks. Figure 3 (b) shows the top view of the V3track distribution. The solidlines indicate the position of the target container and the CFRP vacuum chamber.
3.3 Missing mass distribution
The missing mass for the d(γ, pπ＋π－ )X,
MX c2 ＝√{ (Eγ＋ Md c2) － ( E p ＋ Eπ ＋ Eπ )}2 － c2{ ( pγ＋ pπ ＋ pπ )}2.
＋

－

＋

－

歓

13
is shown in Fig.4 (a). The peak corresponding to the neutron mass is selected as the d(γ, pπ＋π － )n. The
tail in higher energy side is supposed to be from 3π productions. The contamination of this backgroundis estimated to be less than 4%
The MX distribution for the d(γ, pπ－) X is shown in Fig.4(b). The peak at a nucleon mass corresponds
to the d(γ, pπ－) p. The peak at higher energy side is supposed to be double － , triple-pion productions. In
order to reduce them, we imposed cuts on the opening angle between p and π －, cos x pπ ＜ 0.2, and theangle of the pπ－ system,θpπ ＜10°. This cut condition favors the quasi-free (QF) kinematics. The curves－

are the result of two-Gaussian ﬁtting. We selected Mx ＜ 1.1 GeV/c2 as the "n" (γ, pπ－). the "n" denotes

700

neutrons

600

Counts / (10MeV/c 2 )2Counts / (10MeV/c )

5000
4000
3000
2000
1000

400
300
200

(A) (B)1000

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
2

Missing Mass (GeV/c )(a)Fig.4.

500

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
2

Missing Mass (GeV/c )(b)(a) The missing mass distribution for the d(γ, pπ＋π－)X. The peak corresponding to theneutron mass is selected as the d(γ, pπ＋π－)n. (b) The missing mass distribution for the d(γ,pπ－)X. It consists of two peaks as shown by dashed lines. The peak (A) is from d(γ, pπ－) p,
and the peak (B) is thought to be from multi-pion productions.

the bound neutron in the deuteron. The contamination of the multi-pion background is estimated to be
2 ~ 15% in the entire photon energy range.
3.4 Invariant mass distribution
The invariant mass distributions for N π and π＋π－ pair in the γp→ pπ＋π－ reaction are shown in
Fig.5. Curves are the ﬁtting results of Monte Carlo simulations described later. As reported in Refs. [1]and [15], the Δ＋＋π－ channel has a large contribution in this energy region. The peak around 1.35 GeV/c2
in the pπ － invariant mass corresponds to the Δ＋＋π－ channel, and the bump structure around 1.2 GeV/c2
is thought to be the Δ－ .
The neutron momentum distribution for the d(γ, pπ＋π － )n obtained from the missing momentum
is shown in Fig.6. The solid curve corresponding to the nucleon momentum in the deuteron is derived
by the simulation using Hulthén wave function [16]. The peak shifts toward higher momentum
compared to Hulthen wave function because of the momentum resolution of the detected particles. If the14pπ＋π－ ﬁnal state is produced through the QF kinematics with a neutron spectator, the neutron momentum(pn) distribution should correspond to this curve. We selected pn ＜ 0.2 GeV/c as the "p"(γ, pπ＋π － ). The"p" denotes the bound proton in the deuteron. It should be noted that the QF process with a proton
spectator is also possible. But the momentum threshold of the NKS, about 0.25 GeV/c for protons,
precludes the detection of these events almost entirely. We selected pn ＞ 0.3 GeV/c as the non quasi-free(NQF) kinematics in the d(γ, pπ＋π－ )n.

Counts/(20MeV/c2)

Counts/(20MeV/c2)

The N π invariant masses for the γ"p" → pπ＋π－ reaction are shown in Fig.7. They are similar to those

0.85<E <0.90 GeV

1200
1000
800
600
400
200
0
1000

1.00<E <1.05 GeV

800
600
400
200
0

1.00

1.25

1.50

+

2

IM(p ) (GeV/c )

1.00

1.50

0.25

IM(p ) (GeV/c )

1.25

IM(

-

2

0.50

+ -

0.75

) (GeV/c2)

Fig.5. Invariant masses for the γp→ pπ＋π－ reaction at two photon energies. The Δ＋＋π－ channel has
a large contribution in this energy region. Curves show results of Monte Carlo simulations(see text). The dashed, dot-dashed and dotted curves represent the invariant masses for the
Δ＋＋π－ , Δ0π＋ channel and the three-body-phase-space simulation, respectively. The solid curves
are the sums of them.

3500
Counts/(10MeV/c)

3000
2500
2000
1500
1000
500
0

Fig.6.

0

0.2 0.4 0.6 0.8 1 1.2 1.4
Missing momentum (GeV/c)

The neutron momentum distribution for the d(γ, pπ＋π－)n. The solid curve indicates themomentum distribution of the nucleon in the deuteron.

2Counts/(20MeV/c )2Counts/(20MeV/c )150.85<E <0.90 GeV

3000
2500
2000
1500
1000
500
0
2500

1.00<E <1.05 GeV

2000
1500
1000
500
0

1.00

1.25

1.50

1.00

IM(p +) (GeV/c2)

Fig.7.

1.25

1.50

0.25

IM(p -) (GeV/c2)

0.50

0.75

IM( + -) (GeV/c2)

Invariant masses for the γ"p"→ pπ＋π－ reaction at two photon energies. Curves show
results of Monte Carlo simulations (see text). The dashed, dot-dashed and dotted curves
represent the invariant masses for theΔ＋＋π－, Δ0π＋ channel and the three-body-phase-space
simulation, respectively. The solid curves are the sums of them.

1000

0.85<E <0.90 GeVCounts/(20MeV/c2)

800
600
400

IM(p +)

IM(n -)

IM(p -)

IM(n +)

200
0800

1.00<E <1.05 GeV

600
400

IM(p +)

IM(n -)

IM(p -)

IM(n +)

200
01.00 1.25 1.50 1.00 1.25 1.50 1.00 1.25 1.50 1.00 1.25 1.50

Invariant Mass (GeV/c 2 )Fig.8. Invariant masses for the NQF process in the d(γ, pπ＋π－)n at two photon energies. In this case,the peak of the Δ－ also appears. Curves show results of Monte Carlo simulations (see text).
The dashed and dotted curves represent the invariant masses for the Δ＋＋Δ－ channel and thefour-body-phase-space simulation, respectively. The solid curves are the sums of them.

of the γp→ pπ＋ π－ )n. reaction. Figure 8 shows the invariant masses in the NQF kinematics of the d(γ,pπ＋π－ )n. Not only the peak of the Δ ＋＋ but also that of the Δ － can be seen. A two-dimensional display of
pπ＋ and nπ－ invariant mass is shown in Fig.9. This ﬁgure suggests that there exists a large amount of
the simultaneous excitation of two Δs.

16

1.7

-

2

IM(n ) (GeV/c )

1.6
1.5
1.4
1.3
1.2
1.1
1.0
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7
IM(p +) (GeV/c2)
Fig.9. A two-dimensional display of pπ＋ and nπ－ invariant mass.
3.5 Simulation
We have done Monte Carlo simulations, incorporating the geometry of the present experiment, inorder to calculate the NKS acceptance and to separate each channel. The simulation outputs aretransformed into the same format and analyzed in the same way as the experimental data.
We consider the Δ＋＋π－, Δ0 π＋ channel and the three-body-phase-space as the channels in the γp→pπ＋ π－ and γ"p" → pπ＋ π－ reaction. The angular distributions of the Δ＋＋ were taken from Ref. [1]. We
assume an isotropic angular distribution for the p and π＋ in the rest frame of the Δ＋＋. The Δ0 π＋ wastreated in the same manner as the Δ＋＋π－ described above. For the NQF in the d(γ, pπ＋π－)n, the Δ ＋Δ－
channel and the four-body-phase-space were taken into account. TheΔ ＋Δ0 channel should also contribute.
The Clebsh-Gordan coefﬁcients lead to the following probability ratio ofσ ( Δ＋＋Δ－→ p nπ＋π－ )σ ( Δ＋Δ0→ p nπ＋π－ )＝９.

汗The most parts of the Δ＋Δ0-decay contain at least one neutral pion. We exclude this channel, because it
is invisible in the present experiment.
The sum of the simulated invariant masses were ﬁtted to the experimental data. The curves in
Figs. 5, 7 and 8 represent the results of this invariant mass ﬁtting. The fractions of each channel were derived
from this ﬁtting. For example, the fraction of the Δ＋＋Δ－ channel in the γp → pπ＋π－ reaction is given byrΔ π ＝＋＋－

YsimΔ＋＋Δ－

sim ＋＋ －Δ Δ

Y

sim 0 －ΔΔ

＋Y

＋Ysim3BPS，

漢

where the Y sim is the fitted yield of each channel. The subscript 3BPS means the three-body-phasespace. We can obtain the experimental yield of the Δ＋＋π－ channel by

17

YΔ π ＝ Ypπ π rΔ π ,
＋＋

－

＋

－

＋＋

澗

－

where the Ypπ π is the experimental yield of the γp→ pπ＋π－ reaction.
＋－§4. Results and Discussion
The cross section for the i-th channel is calculated by

σi ＝

Yri
n

NT N γ εDAQ εDC εtrack ηi,潅where NT is the number of the target atoms per unit area, Nγ is the number of the incident photons, Y isthe total yield, ri is the fraction of the i-th channel which is obtained by the invariant mass ﬁtting, εDAQ
is the data-acquisition efficiency, εDC is the selection efficiency of track candidates, and εntrack is the
tracking efﬁciency. The number of the reconstructed tracks is n. The acceptance correction factor of thei-th channel ηi is obtained by the simulation and given as the ratio of the number of accepted events tothat of the generated ones. The total cross section is given as the sum of the partial cross sections,
σtot ＝Σσi .

環

The σtot for the γ"n" → pπ－ reaction is shown in Fig.10. The error bars represent the statistical uncertainties.
The results of previous works of Refs. [17-19] are also shown for comparison.
The total cross sections for the γp→ pπ＋π－ and γp→ Δ＋＋π－ reaction are shown in Fig.11 (a) and (b),60this work
Scheffler (1974)
Hilpert (1968)
Benz (1973)

Cross section ( b)

50
40
30
20
10
0

Fig.10.

0.8

0.9

1.0

E (GeV)

1.1

The σtot for the γd→ p pπ－. The ﬁlled circles show the results of this work. The open circles,
squares and triangles represent the results of Shefﬂer et al. [17], Hilpert et al. [18] and Benzet al. [19].

18
respectively. The error bars represent the statistical uncertainties. The results of previous works of
ABBHHM [1] and SAPHIR [15] are also shown for comparison. Our results show good agreement withthem.
The σtot for the γ"p " → pπ＋π－ reaction is shown in Fig.12 (a). The error bars represent the statisticaluncertainties. The results of previous works of Refs. [3, 4, 10] are also shown for comparison. The dataof Refs. [3, 4] were measured using deuteron bubble chambers, while those of Ref. [10] were measured
using a magnetic spectrometer. From the results of Refs. [4, 10] , the cross section values are about 75
μb around E γ = 0.8 GeV. They are close to that of the γp→ pπ＋π－ reaction. But from our results, it turned

90

90

80

80

70
60
50
40
30
this work

20

ABBHHMSAPHIR

10
0
0.5

Cross section ( b)100

Cross section ( b)

100

0.6

0.7

0.8

0.9

E (GeV)

1.0

this work
ABBHHMSAPHIR

70
60
50
40
30
20
10
0
0.5

1.1 1.2

0.6

0.7

(a)

0.8

0.9

E (GeV)

1.0

1.1 1.2(b)

Fig.11. (a) The σtot for the γp→ pπ＋π－. (b) The cross section for the γp→ Δ＋＋π－. The ﬁlled circles
show the results of this work. The open squares and triangles represent the results of
ABBHHM [1] and SAPHIR [15].

this work
Carbonara (1976)
Piazza (1970)
Asai (1993)

80
60
40

0.6

0.8
1.0
E (GeV)(a)Fig.12.

80+ -from n60
40+ -from p

20

20
0
0.4

this work
Piazza (1970)
Carbonara (1976)

100
Cross section ( b)

Cross section ( b)

100

1.2

0
0.4

0.6

0.8
1.0
E (GeV)

1.2(b)(a) The σtot for the γ"p" → pπ＋π－. The ﬁlled circles show the results of this work. The ﬁlled
triangles, open circles and ﬁlled squares represent the results of Piazza et al. [3]. Carbonara
et al. [4] and Asai et al. [10] (b) Comparison with the γ"n" →nπ＋π－. The ﬁlled circles show theresults of this work for the γ"p" → pπ＋π－, The ﬁlled triangles and open circles represent theresults of Piazza et al. [3] . and Carbonara et al. [4] for the γ"n" → nπ＋π－,19out that the cross section values were smaller than the previous results and were about 40 μb. Our
results are in agreement with the results of Ref. [3] . In Fig. 12 (b), the σtot for the γ"p" → pπ＋π－ reaction
are compared with those for the γ"n" → n π＋π－ reaction. Filled triangles and open circles are taken from
Refs. [3, 4], respectively. We conclude that the total cross section for the γ " p" → pπ＋π－ reaction is roughlysame as that for the γ "n" → n π＋π－ reaction. This seems to be consistent considering that the total
photoabsorption cross section on the deuteron is about twice as large as that on the proton.
Figure 13 shows the cross section for the γd → Δ＋＋Δ－ reaction. Filled circles show the results of thiswork. The statistical errors are smaller than the plot size. For comparison the results of previous works
of Refs. [10, 20, 21] are also shown in this ﬁgure. Our results are smaller than others. But the errors ofRefs.[10, 21] are very large. The results of this work shows the decreasing behavior with the photon energy.

100

this work

90

TAGX
SAPHIR

Cross section ( b)80

(PANIC96)

TAGX(unpublished)

70
60
50
40
30
20
10
0
0.5

Fig.13.

0.6

0.7

0.8 0.9 1.0
E (GeV)

1.1

1.2

The cross section for the γd→ Δ＋＋π－. The ﬁlled circles show the results of this work. The ﬁlled
squares, open squares and open triangles represent the results of Asai et al, Wada et al. [20]and Shinozaki et al. [21].

TheΔ＋＋Δ－ production accounts for 4 % at Eγ= 0.8 GeV and 1% at Eγ= 1.1 GeV of the total photoabsorption
cross section on the deuteron.
The cross section for the NQF process has almost no dependency on the photon energy as well as
those of the QF process. The cross section ratio of the NQF to the QF process is found to be σNQF / 2 σQF~ 0.3.

§5. Summary and Conclusion
Total cross sections have been measured for the p(γ, pπ＋π－), "p"(γ, pπ＋π－) reaction and the nonquasi-free process of the d(γ, pπ＋π－)n reaction in the energy range from 0.8 to 1.1 GeV. The total crosssection for the γp → pπ＋π－ reaction shows good agreement with previous data. The quasi-free process was
selected by applying the kinematical cut on the missing momentum. The total cross section for the γ"p"→ pπ＋π－ reaction was found to be 50 ~ 60% compared to that of the "free" proton.

20
The cross section for the γd → Δ＋＋Δ－ reaction was measured. The magunitude is smaller thanprevious data and shows decreasing behaviour with the photon energy.

Acknowledgement
We thank the accelerator and technical stuff at LNS for their contributions to the succsess of theexperiment.

References[1]

Aachen-Berlin-Bonn-Hamburg-Heidelberg-Munchen Collaboration: Phys. Rev. 175 (1968) 1669.

[2]Canbridge Bubble Chamber Group: Phys. Rev. 169 (1968) 1081.

[3]

A. Piazza et al.: Nuovo Cimento 3 (1970) 403.

[4]

Carbonara et al.: Nuovo Cimento 36A (1976) 219.

[5]

F.Härter et al.: Phys. Lett. B40 (1997) 229.

[6]

B. Krusche et al.: Eur. Phys. J. A6 (1999) 309.

[7]

T.A. Armstrong et al.: Phys. Rev. D5 (1972) 1640.

[8]

T.A. Armstrong et al.: Nucl. Phys. B41 (1972) 445.

[9]M. MacCormic et al.: Phys. Rev. C53 (1996) 41.

[10]

M. Asai et al.: Z. Phys. A344 (1993) 335.

[11]

H. Yamazaki et al.: Nucl. Instr. and Meth. A536 (2005) 70.

[12]

Ube Ultra-High Heat-Resistant Polyimide Film, Ube Industries Ltd. (2000).

[13]

Vector Fields Limited, Oxford, England.

[14]

H. Wind : Nucl. Instr. and Meth. 115 (1974) 431.

[15]

C. Wu et al.: Eur. Phys. J. A23 (2005) 317.

[16]

D.H. White, R.M. Schectman, and B.M.Chasan: Phys. Rev. 120 (1960) 614.

[17]

P.E. Schefﬂer and P.L. Walden: Nucl. Phys. B75 (1974) 125.

[18]

H.G. Hilpert et al.: Nucl. Phys. B8 (1968) 535.

[19]

P. Benz et al.: Nucl. Phys. B65 (1973) 158.

[20]

Y. Wada, for the SAPHIR Collaboration: Particles and nuclei international conference, Williamsburg,
Virginia, 1996.

[21]

A. Shinozaki, for the TAGX Collaboration: private communication.

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

21(LNS Experiment : #2467)

Study of Giant Resonances in the 24Mg (e, e'α) Reaction
K. Takahashi1＊ , K. Abe1, R. Hashimoto2, Y. Hayashi2, K. Hirose1, T. Ishikawa2,
H. Kanda1, K. Maeda1, H. Miyase1, I. Nishikawa2, Y. Sato2, T. Tamae2,
H. Tsubota1, M. Utoyama1, M. Wakamatsu1, M. Watabe2, Y. Yamaguchi1
1

Physics Department, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-0845
2

Laboratory of Nuclear Science, Tohoku University, Mikamine, Taihaku-ku, Sendai 982-0826§1. Introduction
The giant resonances in light nuclei have been investigated by the ( e, e' α ) reaction in several
nuclei. In 12C and 40Ca, where the ( e, e' α ) reaction through the E1 transition is considered to beforbidden by the isospin selection rule because these are Z = N nuclei. The reported E1 strength wasvery small or neglected and the E2 or E0 strength was dominant [1,2]. Concerning the E0 excitation,
there are intensive studies by alpha scattering with the intention to ﬁnd the isoscalar giant monopole
resonance (ISGMR) [3-8]. The ISGMR is interesting with regard to the compressibility of nuclear
matter. Considering that the ( e, e' α) reaction occurs only through isoscalar resonances, the ( e, e' α)
reaction can be an alternative tool for searching the ISGMR. However, only a fraction of the ISGMR
strength is related to α emission channels, although one can reconstruct the strength by using thestatistical model for example [2].
This work reports an investigation of the excitation and decay of the giant resonances in 24Mg ( e,e' α) reaction.

§2. Experiment
The experiment was performed at Laboratory of Nuclear Science (LNS) in Tohoku University at anincident energy of E0 =199.31MeV and a scattering angle of θe = 30°, corresponding to a momentum
transfer of q = 0.51 fm-1, using a continuous electron beam from the Stretcher-Booster Ring. A typicalelectron current during the experiment was from 0.5 to 1 μA.
A 24Mg foil of 2mg/cm2 and 99.99% enriched was used as a target. The thickness was ﬁxed so thatthe energy loss of emitted α particles in the target is not too large. The scattered electrons weredetected by is a double-focusing magnetic spectrometer with a solid angle of 6 msr. A vertical drift
chamber (VDC) was used for detecting the electrons on the focal plane of the spectrometer. Three layersof plastic scintillator were set behind the VDC for trigger of data acquisition. With 5 % of acceptance ofthe spectrometer, the range of the excitation energy was 15-25 MeV. In this energy range, proton,
deuteron, triton, and α particles can contribute to the charged particle decay. The range was chosen
Present address: ART KAGAKU Co.,Ltd, Muramatsu, Tokai-mura, Naka-bun, Ibaraki 319-1112＊

22
because the α decay strength of 24Mg ( e, e' α ) reaction was very small around 20 MeV or higher
according to previous experiments.
Emitted charged particles were detected in coincidence with scattered electrons by using 12 SSD
telescopes which consists of two layers of SSD. The ﬁrst SSD was 50 μm thick and the second was 1
mm thick.

These telescopes were placed in a plane rotated about q axis by φ =90°. With the out-of-plane detection, the telescopes were able to be arranged without disturbing the electron beam andscattered electrons. Furthermore, an analysis is easier because the longtudinal-transverse interferenceterm vanishes.

§3. Experimental Results and Analysis
Figure 1 shows an example of the missing energy spectrum. According to the Bethe-Bloch formula,the energy loss of α particles in the target is not negligible. So it was taken into account assuming thatthe emitted particles pass a half of the target thickness.
The separation of α0 and α1 events were done by ﬁtting two components of α0 and α1 generated by
calculation to the experimental spectrum as shown in Fig. 2, because the energy resolution was notenough to separate the peaks clearly. A function used for the ﬁtting isg ( Emiss ) = a0 fα0 ( Emiss － b, σ) + a1 fα1 ( Emiss － b, σ ) + c ,敢������

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Fig. 1.

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Missing energy spectrum for excitation energys from 15 to 25 MeV. The excitation energyof the ﬁrst excited state is 1.14 MeV. It was corrected for the energy loss in the target using
the Bethe-Bloch formula by assuming that particle emissions started at the center of thetarget.

where fα0 and fα1 are functions for the contributions of α0 and α1, individually, generated by calculation ;Emiss is the missing energy, σ is the energy resolution of each of SSD telescopes, and a0, a1, b, c are freeparameters. Considering low quality of statistics of our data, the most likelihood method was used forﬁtting by utiliyzing MINUIT for maximization of the likelihood [9].

������

23

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Fitting of the missing energy spectrum with the spectrum generated by the calculation.
Hatched histogram is the sum of the calculations ﬁtted with α0, α1 and the background.
The calculation takes into account the initial energy of α, the energy loss while passing
through the target, and the resolution of detectors.

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Fig.2.

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Fig.3.

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Angular distribution ofα0 for excitation energies of 15-16.4 MeV. The solid line shows aresult of ﬁtting by Eq.(2).

Figure 3 shows the angular distribution of the ( e, e' α0) reaction extracted by the method describedabove. The curve in the ﬁgure shows the angular correlation function which we discuss later.

§4. Discussion
In case of spin and parity of J π = 0+ for all of the target, residual nucleus, and emitted particle, the24( e, e' α) differential cross section with multipolarities up to 3 can be simpliﬁed as following [10]:3d5 σ＝σMott ∑√￣￣￣￣￣￣(2L+1) A0 (L) FCL eiδ LPL (cosθα )dωdΩe' dΩα
L=0

2

0

,

柑

0

where σMott is the Mott cross section, FCL is the longitudinal electric form factor, A0(L) is the decaycoefficient, δL is the phase of the product of FCL and A0(L). Taking √￣￣￣￣￣￣(2L+1) A0 (L) FCL and δL as freeparameters, fitting by χ 2 minimization was performed. In the 24Mg (e, e' α 0) reaction, the angularmomentum of the excited state J is deﬁned unambiguously as equal to L because spins of the groundstate of the residual nucleus and the emitted particle are zero. Concerning the upper limit of＿ 2 or L ＜＿ 3 is adequate. In the 26Mg (e, e' α) experiment [10], its momentum
multipolarity in Eq.(2), L ＜trasfers are 0.35 and 0.54 fm-1, that are very close to ours. The E3 component was not included in themultipole decomposition because it was supposed to be negligible by the DWBA calculation. It was notincluded also in 40Ca (e, e' α ) experiment [2]. In those results, there is a discrepancy between theexperimental angular distribution and the ﬁtted curve at 0°. On the other hand, the result of the 12C (e,e' α ) experiment [1] at in q ＝ 0.24-0.61 fm-1 shows a relatively better ﬁtting result at 0°by including
the E3. Furthermore, 39% of the E3 EWSR (energy weighted sum rule) has been found in 24Mg (e, e' )＿ 3 in Eq.(2). The solid
reaction. Considering these facts, we included the C3 component by deﬁning L ＜line in Fig. 3 is the result of ﬁtting by χ2 minimization.
Using the parameters obtained by the ﬁtting, the cross section for each multipolarity is given byd5σL
dωdΩe'＝σMott (2L+1) A0 (L)｜FCL｜2∫[PL (cosθα )]2dΩα
0

・

0

桓

Using the values obtained from the fitting, we deduced the strength function BCL(q) which can be
represented for spin 0 nuclei by the ﬁrst Born approximation as follows [11],BCL(q) ＝（ q ）f q [(2L + 1)!! ] }

dσ
dΩe'

{

4πσ1Mott

dσ
dΩe'

{

4πσ1Mott

CL

Δ2

2

rec

2

2L

-2

-1

棺

＿ 1, andfor L ＞BCO(q) ＝CO（ q ） f q [15] }
Δ2
2

2

rec

4

-2

-1

款

for L ＝ 0, where σ 1Mott is the Mott cross section for Z ＝１, ∆2 = q2 － ω2, and frec is described by[frec ～ 1+

]

2k1
θ -1
sin2
.
M
2

歓

Furthermore, BCL(q) can be expanded as following,（）

BCL(q)＝１－
BCL(q=0)
１―
２

q2 ＜ r2CL ＞ tr
2 (2L+3)＋

q4 ＜ r4CL ＞ tr
－ ……,
8 (2L+3) (2L+5)

汗25＜ r lCL ＞ tr ＝

∫ rL+l+2ρL(r)dr,∫ rL+2ρL(r)dr

漢＿ 1, andfor L ＞（）

BC0(q)
q2 ＜ r2C0＞ tr
q4 ＜ r4C0＞ tr
＝１－
＋
－ ……,
BC0(q=0)
20
840
１
―
２

＜ r lC0＞ tr ＝

∫ r l+4ρ0(r)dr∫ r 4ρ0(r)dr澗潅

for L = 0. ρL(r) is the transition charge distribution which is described by Tassie model [12],ρL(r) ∝ r L-1

dρg.s.(r)dr環＿ 1, andfor L ＞
ρ0(r) ∝ 3ρg.s.(r) + r

dρg.s.(r)dr甘for L = 0, where ρg.s.(r) is the charge distribution for the ground state described by the three parameter
Fermi model,）

監（ω, c, t ）＝（－ 0.249, 3.192, 0.604）

看ρg.s.(r) ＝（１＋

（

-1
r－c
ωr2
（
） .
2 ） 1+ exptt

In Eq.(13), we used parameters

according to Ref. [12].
BCL( q ＝ 0) for individual multipolarities was obtained by calculating the right-hand side of Eqs. (7)and (9) for q ＝ 0.51 fm-1, and applying BCL(q) given by Eqs. (4) and (5). Eventually, the strength at thephoton point, BCL( q ＝ ω ) was obtained by substituting the BCL( q ＝ 0) to Eq. (7) or (9).
Using the BCL( q ＝ ω ) obtained above, the fraction of the energy weighted sum rule (EWSR) is givenby
R＝BCL(ω) ω× 100,EWSR ( EL, ΔT )where values of the EWSR are given as follows [13],S( E0) ＝(2h− )2 Z2＜ r2 ＞ ,
mp A

竿

26

9h− 2
8πmp

S( EL, L ＞ 1) ＝

L(2L+1)2h− 28πmp��������������������

��������������������

��������������������

��������������������

S( E1, ΔT=1) ＝

NZ
,
A
Z2
＜ r2L-2 ＞ ,
A

管

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Fig.4. Fraction of the energy weighted sum rule for individual multipolarities.

Figure 4 displays the fraction of the EWSR obtained by Eq. (15), and the result is summarized inTable 1 with results of other experiments. Most of the strength was detected between 15 and 20 MeV. It
must be affected by competition between various decay channels. Actually the E0 strength with 1.2% of
the E0 EWSR was detected, while α scattering [6] found 72% with the centroid energy of 21 MeV. The
E1 strength with 0.4% of the E1 EWSR was found, which is comparative with the (α, γ0 ) reaction, andvery small comparing with the (γ, p0 ) reaction. This is the effect of the suppression by the isospin
selection rule. The E2 strength with 0.8% of the E2 EWSR was found. Its distribution is similar to (α,γ)[14] reaction although the amount is different.
In the analysis of electron scattering [15], the separation of E0 and E2 was not possible by principle.

27

Table 1. Summary of strength obtained by this work and other experiments on 24Mg.
＿
L＞

experimentω (MeV)R (% EWSR)

Mg (e, e'α0 )15.0-25.0

1.2 ± 0.2

Mg (α, α)[6]0-4172 ± 10Mg (e, e'α0 )[10]14.0-26.0

0.2

Mg (e, e'α0 )15-25

0.4 ± 0.1

Mg (e, e')[15]

9.0-34.0

84.9

Mg (e, α0 )[16]13.5-22.5

0.43

Mg (γ, p0 )[17]15.1-23.0

3.3

Mg (γ, n)[18]

16.5-28.0

14.0

Ne (α,γ0 )[14]

14.6-20.6

0.33

Mg (α, α)[6]

0-41

81＋26
−14

Mg (e, e'α0 )[10]14.0-26.0

0.45

Mg (e, e'α0 )15-25

0.8 ± 0.1

Mg (e, e')[15]

0.0-34.0

117

Mg (e, α0 )13.5-22.5

6.0 ± 0.5

Ne (α, γ0 )[14]12.0-22.5

11.8 ± 1.0

Mg (α, α)[6]0-4172 ± 10Mg (e, e'α0 )[10]14.0-26.0

1.4

Mg (e, e'α0 )15-25

4.8±2.1

Mg (e, e')[15]

0.0-34.0

115

Mg (α, α)[6]

0-41

31＋9
−6

0

24

0

24

0

26

1

24

1

24

1

24

1

24

1

24

1

20

1

24

1

26

2

24

2

24

2

24

2

20

2

24

2

26

3

24

3

24

3

24

Figure 5 shows comparison between the C2(C0) differential form factor from (e, e' ) inelastic scatteringand our results of C0 and C2 differential cross sections. Comparison is limited to the excitation energies
below 20 MeV because the cross sections in our data are small above it. There is a peak around 15 MeV
in the (e, e' ) reaction. The C0/C2 ratio is estimated from the present experiment as C0/C2 = 5 for thecorresponding energy bin (15 ～ 16.4 MeV). For a peak between 16 and 18 MeV observed in the (e, e' )reaction the present result represents that C2 is dominant. The C0/C2 ratio is obtained as C0/C2 = 0.9
between 16.4 ～ 17.3 MeV, and C0/C2 = 0.15 between 17.3 and 18.0 MeV from our data.
Concerning the C3, the strength was 4.8% of the E3 EWSR. The validity of including E3 can beprovided from the q dependence of the form factor investigated in the inelastic scattering experiment.
In the inelastic scattering experiment, a signiﬁcant amount of E3 strength was detected at q = 0.73 fm-1.
According to the q dependence, the C3 strength at q = 0.51 fm-1 (our experiment) is smaller than C3 at
q = 0.73 fm-1 by a factor of 4. This difference is not too large to expect the presence of that at q = 0.51
fm-1. Furthermore, we compared the ratio C3/C2 of the inelastic scattering data and of our work. The
strength was reconstructed by the method of statistical model when calculating the ratio for our work.
Then we obtained C3/C2 = 0.35 for the inelastic scattering data and 0.48 for our work in the range of

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28

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Fig.5.

���������

The Differential form factor of C2(C0) at q = 0.73 fm-1 from (e, e') experiment [15](top),
differential cross section of C0 (middle), and C2 (bottom) of our expemriment.

15-19.8 MeV.
In the same manner, we compared the C1/C2 ratio in order to examine how much the C1
suppression can be seen. It was 1.79 for the inelastic scattering data and 0.79 for our work, that means
the isospin mixing occured with the rate of 44%. That is 24% in the ( e, α) [10] and (α, γ) [14]experiments.

§5. Conclusion
The 24Mg(e, e' α) experiments was performed at q = 0.51fm-1 and in the range of excitation energy of
15-25 MeV.
From analysis of the angular distribution for α0 channel, the C0, C1, C2 and C3 form factors were29
decomposed to obtain the strength distribution for each multipolarity. The C0 and C2 components,
which was not able to be decomposed by ( e, e' ) data, were separated and the result indicated that theC0 excitation is dominant around 15-16 MeV and the C2 (C0) peak at 17 MeV found in the ( e, e' )experiment is identiﬁed to be C2 from our result. From the comparison of the C1/C2 ratio for the datawith ( e, e' ) result, it was found that the isospin mixing occurs with the rate of 41% in the E1 excitation.
In our multipole decomposition, the C3 component was included that was sometime igonored orneglective in previous studies. Comparing the C3/C2 ratio with the ( e, e' ) result, the C3 strength which
we obtained is thought to be reasonable. The C1 suppression by the isospin selection rule probably
makes the C3 easier to be identiﬁed. Although it was clear that only a fraction of strength can be seenin the ( e, e' α) reaction, the coincidence experiment can decompose the C0 and C2 components. Better
statistics is required to discuss more precisely.

References[1]

D.J. DeAngelis, J.R. Calarco, J.E. Wise, H.J. Emrich, R. Neuhausen, and H. Weyand: Phys. Rev.
C52 (1995) 61.

[2]

M. Kohl, P. von Neumann-Cosel, A. Richter, G. Schrieder, and S. Strauch: Phys. Rev. C57 (1998)
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[4]

Y.W. Lui, J.D. Bronson, D.H. Youngblood, Y. Toba, and U.Garg: Phys. Rev. C31 (1985) 1643.

[5]

S. Shlomo and D.H. Youngblood: Phys. Rev. C47 (1993) 529.

[6]

D.H. Youngblood, Y.-W. Lui, and L. Clark: Phys. Rev. C60 (1999) 014304.

[7]

D.H. Youngblood, H.L. Clark, and Y.-W. Lui: Phys. Rev. C65 (2002) 034302.

[8]

B. John, Y. Tokimoto, Y.-W. Lui, H.L. Clark, X. Chen, and D.H. Youngblood: Phys. Rev. C68 (2003)
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[9]

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[10]

L.A.A. Terremoto, V.P. Likhachev, M.N. Martins, H.J. Emrich, G. Fricke, Th. Kröhl, and K.W. Neff :Phys. Rev. C56 (1997) 2597.

[11]

T. deForest Jr. and J.D. Walecka: Adv. Phys. 15 (1966) 1.

[12]

L.J. Tassie: Austr. J. Phys. 9 (1956) 407.

[13]

R. Pitthan, F.R. Buskirk, W.A. Houk, and R.W. Moore: Phys. Rev. C21 (1980) 28.

[14]

E. Kuhlmann, E. Ventura, J.R. Calarco, D.G. Mavis, and S.S. Hanna: Phys. Rev. C11 (1975) 1525.

[15]

K. Itoh, S. Osawa, Y. Torizuka, T. Saito, and T. Terasawa: Phys. Rev. C23 (1981) 945.

[16]

M. Hirooka, T. Tanaka, T. Hino, A. Tanaka, T. Tamae, M. Sugawara, and M. Miyase: Nucl. Phys.
A431 (1984) 269.

[17]

R.C. Bearse, L. Meyer-Sch\ützmeister, and R.E. Segel: Nucl. Phys. A116, (1968) 682.

[18]

S.C. Fultz, R.A. Alvarez, B.L. Berman, M.A. Kelly, D.R. Lasher, and T.W. Phillips: Phys. Rev. C4(1971) 149.

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

31(LNS Experiment : #2446, #2506)

Status Report of Neutral Kaon photo-production study using
Neutral Kaon Spectrometer 2 (NKS2) at LNS-Tohoku
N. Chiga1, T. Fujibayashi1, Y. Fujii1, K. Futatsukawa1, O. Hashimoto1,
K. Hirose1, H. Kanda1, M. Kaneta2, D. Kawama2, Y. Ma2, K. Maeda2,
N. Maruyama2, A. Matsumura2, M. Matsuzawa2, Y. Miyagi2, H. Miyase2,
S.N. Nakamura2, K. Nonaka2, Y. Okayasu2, K. Shirotori2, H. Tamura2,
K. Tsukada2, T. Ishikawa3, K. Suzuki3, T. Nakabayashi3, H. Shimizu3,
T. Tamae3, H. Yamazaki3, A. Sasaki4 and O. Konno5
1
2

Department of Physics, Tohoku University, Sendai, Miyagi 980-8578
Department of Physics, Tohoku University, Sendai, Miyagi 980-8578

3

4
5

Laboratory of Nuclear Science, Tohoku University, Sendai, Miyagi 982-0826
Department of Electrical and Electric Engineering, Akita University, Akita, Akita 010-8502

Department of Electrical Engineering, Ichinoseki National College of Technology, Ichinoseki, Iwate 010-8502§1. Introduction
So far the elementary photo-strangeness production process has been intensively studied based on
the high-quality data of the charged kaon channel, γ + p → K + + Λ（Σ0). However, there were no reliabledata for the neutral kaon channel γ + n → K S0 + Λ and the theoretical investigations suffer seriously
from the lack of the data. In order to have reliable data for the neutral kaon photo-production data, wehave been putting an effort to measure the γ + n → K S0 + Λ process in the π+ π- decay channel, using aliquid deuterium target and a tagged photon beam in the threshold region at Laboratory of Nuclear
Science, Tohoku University.We have already taken exploratory data quite successfully with use of
Neutral Kaon Spectrometer (NKS) at LNS-Tohoku in 2003 and 2004.
We intend to extend the previous experiment by considerably upgrading the original neutral kaon
spectrometer to a completely new neutral kaon spectrometer (NKS2), fully replacing the spectrometer
magnet, tracking detectors and all the trigger counters. The new spectrometer NKS2 has signiﬁcantly
larger acceptance for neutral kaons compared with NKS, particularly covering forward angles, andmuch better invariant mass resolution. The estimated acceptance of NKS2 is about 3 to 4 times (dependon momentum and theoretical model) larger for K S0 than that of NKS. Additionally, it is about 8 to 10
times larger for Lambda. With this advantage, we expect simultaneous measurements of K S0 and Λ.
Additionally, we plan to measure other strangeness production channels and also Λ hyperon
polarization in γ + n and γ + p reactions.

§2. General setup of the NKS2 Experiment
The NKS2 spectrometer is located on the BM4 beam line of the second experimental hall ofLaboratory of Nuclear Science (LNS), Tohoku University (see Fig. 1). The incident beam from LINAC

32

Fig.1. The outline of the second experimental hall of LNS (see text in detail).

has 0.2 GeV of the beam energy and is accelerated up to 1.2 GeV in Stretcher-Booster (STB) Ring. The
photon beam is created as bremsstrahlung of electron by a carbon wire at STB Tagger system of
Bending Magnet 4 (BM4). There is a dipole magnet which is called the sweep magnet for e+e- fromphoton conversion. The sweep magnet is the same one that was used in the previous experiment NKS.
The spectrometer is placed following the sweep magnet. The main magnet (680 magnet) is a dipole
which is renovated from a cyclotron magnet of Cyclotron RI Center of Tohoku University. Detectors of
NKS2 are: Inner Hodoscope (IH), Straw Drift Chamber (SDC), Cylindrical Drift Chamber (CDC), Outer
Hodoscope (OH), and Electron Veto counter (EV). Detector positions are shown in Fig.2, and 3D views
are in Figs. 3 and 4. The detail description of the beam line and the spectrometer will be shown in thefollowing section.

§3. Status of the ExperimentCommissioning runs were carried out in Jan. Mar, Jun., and Sep. 2006. using a carbon target.
During those runs, we studied the detector performance, data acquisition system, and trigger rate.
The run of January (17-20) was used to tune the tagging counter and hodoscopes. In the originalschedule, the March run (Mar. 7-12) was planned to be used to check the detector system including
CDC and hodoscopes. There, however, was an accident of breaking a Mylar window of CDC, therefore
this run was used for the trigger study. The CDC was repaired after this beam time and became being
ready before the next beam time. In June 6-15, we had two weeks data taking with a natural carbon
target. About two third of the beam time was used for the ﬁnal detector setup: tune of counter gain and

33

���

���

���

���
��
�� ��

������

γ ����
��γ ����

Fig.2. A schematic view of NKS2. The photon beam direction is from bottom to top in the ﬁgure.
The target holder will be at center of magnet. The detectors are (the order is from center toouter): Inner Hodoscope (IH), Straw Drift Chamber (SDC), Cylindrical Drift Chamber(CDC), Outer Hodoscope (OH, Vertical (OHV) and Horizontal (OHH) ), and Electron Veto
counter (EV). Note that EV is placed at downstream of OHV but not shown in the ﬁgure.

Fig.3.

A 3D view of the spectrometer viewed from the upstream of the beam line. We can see apart of OHH on the magnet yoke and OHV around the magnet coil.

34

Fig.4.

A 3D view of the spectrometer viewed from the downstream of the beam line. There are
OHV around the magnet coil and OHH on the magnet yoke. The EV counters are placedfollowing OHV. The OHV and EV counters are supported by aluminum chassis.

threshold of discriminator, noise reduction, ﬁxing some troubles of DAQ, making chambers be ready.
Trigger study and data taking were done in the rest of the beam time. The main purpose of theSeptember run (Sep. 25-Oct. 2) was data taking with the carbon target. Additionally, the length of avacuum pipe between the pair magnet and the target was extended to reject the background fromphoton conversion. Finally, we started data taking with a liquid deuteron target on November 2.

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

35(LNS Experiment : #2446, #2506)

Construction of a Forward Electro-magnetic Calorimeter
SCISSORS Ⅲ
T. Ishikawa, H. Fukasawa, R. Hashimoto, T. Ishida, J. Kasagi, S. Kuwasaki,
F. Miyahara, K. Mochizuki, T. Nakabayashi, K. Nawa, Y. Okada, K. Okamura,
Y. Onodera, Y. Saitoh, H. Shimizu, K. Suzuki, H. Yamazaki, and H. Yonemura
1Laboratory of Nuclear Science, Tohoku University, Sendai, Miyagi 982-0826

A new electro-magnetic calorimeter complex FOREST with a solid angle of about 4π in total isunder construction. It consists of three calorimeters: a forward one with CsI crystals, a middle one withlead scintillating ﬁber modules, and a backward one with lead glass Čerenkov counters. Recently, theforward calorimeter SCISSORS Ⅲ takes shape.

§1. An Electro-magnetic Calorimeter Complex FOREST
Nucleon resonances were experimentally studied via π0 and η photo-production by using anelectro-magnetic calorimeter SCISSORS Ⅱ in the GeV-γexperimental hall. Theπ0 and η mesons wereidentiﬁed inγγinvariant mass distributions. When more than one neutral mesons were produced andeach of these decays intoγγ, the possible choice of two γ's is not unique. Thus the events were
contaminated in these distributions that two γ's were detected which different neutral mesons decay
into and the others were not detected. Since a solid angle of SCISSORSⅡis only 12.6% of 4π, a fractionof these events was large.
To suppress the contamination, a large solid angle calorimeter is required so that a fraction of
undetectedγshould decrease. A new electro-magnetic calorimeter complex with a solid angle of about
4πin total has been planned [1]. The complex is called Four-pi Omnidirectional Response Extended
Spectrometer Trio (FOREST). It consists of three calorimeters: a forward one with CsI crystals
ʻSCISSORS Ⅲ,ʼ a middle one with lead scintillating ﬁber modules ʻLEPS Backward Gamma,ʼ and abackward one with lead glass Čerenkov counters. Figure 1 a) shows a slant view of FOREST.
The SCISSORS Ⅲ consists of pure CsI crystals which had composed SCISSORS Ⅱ . The shape of
CsI crystal modules is a truncated regular hexagonal pyramid. Among these modules, thickness of 144
crystals is 300 mm (LNS type) and that of 48 ones are 250 mm (INS type). Central units of SCISSORS
Ⅲ are the LNS type, and peripheral ones are the INS type. Figure 1 b) shows the arrangement ofmodules in SCISSORS Ⅲ [2,3].

§2. Arrangement of CsI Crystal Modules
Because an equilateral hexagon has an interior angle of 120°, it can be used to tile the plane
without holes like a honeycomb. Neither front nor rear faces of a truncated hexagonal pyramid compose

36

Fig.1. a) Slant view of the new electro-magnetic calorimeter complex FOREST. Polar angles of 4°27°, 30°-100°, and 106°-170°are covered with CsI crystal array ʻSCISSORS Ⅲ ,ʼ with lead
scintillating ﬁber module array ‘LEPS Backward Gamma,’ and with lead glass Čerenkov
counter array, respectively. b) Schematic view of the module arrangement in SCISSORS Ⅲ.
Central units are the LNS type, and peripheral ones are the INS type.
a segment of a regular solid without overlap. It is required to array truncated regular hexagonal
pyramids tight.
Let's consider a crystal is laid out adjacent to the central one. When two crystals are arranged sothat the contact side face of the central one is identical with that of the adjacent one as shown in
Fig.2(a), the volume of the adjacent one exceeds the angle formed by two vectors to the vertices of thefront face of the central one sharing the center of the central one as an endpoint. Hence, another one
cannot be laid out similarly adjacent to each of the two without overlap. If the adjacent one is slid
rearward so that side faces contact, the adjacent one can be set that does not exceed the allowed region
as shown in Fig.2 (b). Numerically, the step of rear LNS type crystal faces should be larger than 4 mm
and that of two different type crystal faces should be larger than 40 mm [2].
�� ���������

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���������������
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���������������
����������������

Fig.2.

����������������
���������������

����������������

The arrangement of two CsI crystal modules. a) Two crystals are arranged so that thecontact side face of the central one is identical with that of the adjacent one. b) The
adjacent crystal is slid rearward. In the front view, the volume of the adjacent one should
not exceed the angle formed by two vectors to the vertices of the front face of the central
one sharing the center of the central one as an endpoint.

37§3. Constructed SCISSORS Ⅲ
The crystal arrangement was made from 24th April to 13th May in 2006. Figure 3 shows theconstructed SCISSORS Ⅲ . Since individual differences in the module shape exist, crystals are not laidout ideally. The step of rear LNS type crystal faces is about 10 mm at maximum. The front crystal faces
cover from 60-460 mm in radius from z-axis. The position and direction of each crystal shall bemeasured in the near future.

Fig.3. Constructed SCISSORS Ⅲ . The left panel shows a front view, and the right shows a rearone.

References[1]

T. Ishikawa: LNS Experiment #2536 (2005).

[2]

T. Ishikawa: Internal GeV-γanalysis note No.37 (2006).

[3]

H. Fukasawa: Internal GeV-γanalysis note No.09 (2005).

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

39(LNS Experiment : #2446, #2506)

Installation of a Dipole Electromagnet RTAGX
T. Ishikawa1, R. Hashimoto1, T. Ishida1, J. Kasagi1,
S. Kuwasaki1, F. Miyahara1, K. Maeda2, K. Mochizuki1,
K. Nawa1, Y. Okada1, Y. Onodera1, H. Shimizu1, K. Suzuki1, and H. Yamazaki1
1

Laboratory of Nuclear Science, Tohoku University, Sendai, Miyagi 982-0826
2

Department of Physics, Tohoku University, Sendai, Miyagi 980-8578

A dipole electromagnet RTAGX has been installed in the GeV-γ experimental hall. It sweeps out
charged particles contaminated in the incident γ beam for meson photo-production experiments. It also
supplies momentum-analyzed electrons or positrons in a newly constructed test beamline.

§1. RTAGX Magnet
A dipole electromagnet RTAGX was installed in the GeV-γ experimental hall from 13th to 15th
December in 2005. This magnet was originally created as a 1/1.645 scale model for a sector focused
cyclotron at Institution of Nuclear Study, University of Tokyo [1]. It had come to be used as a large
acceptance spectrometer TAGX [2] for photon induced nuclear and hadron experiments, where theshims and pole tips were removed and the gap was expanded from 210 mm to 600 mm by inserting twoiron blocks into vertical return yokes. It was moved to the second experimental hall in 2000 and wasused as a Neutral Kaon Spectrometer (NKS). The NKS was replaced by a larger magnet, and it waspreserved in a warehouse until SCISSORSII experiments ﬁnished.
The magnet was installed in the GeV-γ experimental hall. The inserted two iron blocks were
removed and its gap became 210 mm again. We call it Return of the TAGX or Recycled TAGX (RTAGX).
Figure 1 shows the installed RTAGX.
The pole faces are circle with a diameter of 1070 mm, and holes are drilled in the poles and yokesat the center of these with a diameter of 100 mm. The two hollow-conductor pancake-shaped coils arelaid out, and the number of turns is 480 in total. It sweeps out charged particles contaminated in theincident γ beam for meson photo-production experiments. It also supplies momentum-analyzed
electrons or positrons in a newly constructed test beamline.

§2. Magnetic Flux of RTAGX
The magnetic flux of RTAGX was calculated by a 3D magnetostatics computer code Radia [3],which is interfaced to Mathematica on Microsoft Windows XP. Figure 2 shows the magnetic ﬂux By as afunction of z position for the TAGX and RTAGX setups with a current of 500 A. The By at the center is0.483 T and 1.183 T, and the B狩 integration is 0.641 Tm and 1.549 Tm for the TAGX and RTAGX,
respectively. The strong magnetic flux of about 1.2 T at maximum is achieved in the RTAGX by

40

Fig.1.

Installed RTAGX. The pole faces are circle with a diameter of 1070 mm, and the gap
between them is 210 mm.

contracting the gap to 210 mm.
The magnetic ﬂuxes at three points were measured by a calibrated Hall generator with different
coil currents. Figure 3 shows the measured magnetic ﬂuxes By at three points with various coil currents.
The realistic magnetic ﬂux map was determined by normalizing calculated one for each coil current
setup so that it reproduces the measured magnetic ﬂux at the position (0,0,160) where the measured
magnetic ﬂux was not inﬂuenced by the precise position of the Hall generator.

§3. Electron and Positron Test Beamline
The RTAGX can be used to analyze momenta of charged particles with a high resolution since Bx〜−0

and Bz〜−0 in the horizontal plane. When the incident γ beam irradiates a target in front of the RTAGX,
some photons convert into positron and electron pairs. The created positrons and electrons are bent by
the magnetic ﬂux, and a monochromatic electron or positron beam can be obtained at a speciﬁed angle[4]. Figure 4 shows the analyzed momentum as a function of RTAGX current at 30 °with respect to z
axis.
�
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� ���

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�������

� ���

� ���

� ���
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��

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�

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� ����� ������������

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Fig.2. Magnetic ﬂux By as a function of z position. The left panel shows that for the TAGX with agap of 600 mm, and the right shows that for the RTAGX with a gap of 210 mm.

41

����

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����
���

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���
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���
�
�

Fig.3.

���

���
���
�������������

���

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Measured magnetic fluxes By at three points with different coil currents. The deep graycircle, rectangle, and triangle markers show those at (0,0,0), at (0,0,160), and at (0,0,535),
respectively, where the coil currents are set in the decreasing direction. The light graycircle, rectangle, and triangle ones show those at (0,0,0), at (0,0,160), and at (0,0,535),
respectively, where the coil currents are set in the increasing direction.

A Au foil with a thickness of 20μm is placed 878 mm upstream of the pole center, and a leadcollimator with a diameter of 20 mm and with a thickness of 100 mm is laid out 2445 mm downstream
at the － 30 °with respect to z axis. The momentum resolution of the obtained beam depends mainly on
the energy loss and multiple scattering of the positrons or electrons during penetrating the Au foil and���������������������

���
���
���
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���
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�

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Fig.4. Analyzed momentum as a function of RTGX current at 30 °with respect to z axis. The data
points are compared with p(I) = 2.0220 I － 1.7947 × 10 − 9 I4.0600 Mev/c.

42
the air on the way. It is roughly 2％ although it should be estimated more precisely. The positron andelectron beams are obtained with little contamination, and counting rates of these are about 3 kHz
independently of the RTAGX current with a STB circulating current of 15 mA.

References[1]

T. Tanabe et al.: INS internal report INS-J-133 (1972).

[2]

K. Maruyama et al.: Nucl. Inst. Meth. in Phys. Res. A 376 (1996) 335.

[3]

P.Elleaume, O.Chubar, and J.Chavanne: Computing 3D Magnetic Fields from Insertion Devices,
Proceedings of PAC97;
O.Chubar, P.Elleaume, and J.Chavanne: A 3D Magnetostatics Computer Code for Insertion
Devices, Proceedings of SRI97;
http://www.esrf.fr/Accelerators/Groups/InsertionDevices/Software/Radia/.

[4]

H.Shimizu: LNS Experiment #2563.

Ⅱ．Radiochemistr y

核理研研究報告

第39巻

2006

43

(LNS Experiment : #2543, #2560)

高純度酸化ガドリニウム試薬中のカリウムの光量子放射化分析
大浦泰嗣，佐々木愛，海老原充
首都大学東京大学院理工学研究科（192-0397

東京都八王子市南大沢 1-1）

Photoactivation Analysis of Potassium in High Purity
Gadolinium Oxides
Y. Oura, A. Sasaki, and M. Ebihara
Graduate School of Science and Engineering, Tokyo Metropolitan University,
1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0372
A potassium content in high purity gadolinium oxide reagents, which is a component of the detector
for the neutrino in the "KASKA" project, was determined by photoactivation analysis. Applying
radiochemical processing, 0.1 ppm of upper limit was obtained. The gadolinium oxide reagent
determined in this study was conﬁrmed to meet the request for materials in the detector.

§１．はじめに
現在世界的にニュートリノに関する大型研究プロジェクトがいくつか進行あるいは計画されている。その中の一つが，“KASKA”プロジェクトである［1］。このプロジェクトは，原子炉ニュートリノを用いてニュートリノ振動θ13 現象の解明を目指している。ニュートリノは物質との相互作用がまれなため，通常，非常に大きな検出器が用いられるが，KASKAでは，ガドリニウム（Gd）原子を含んだ液体シンチレータによるニュートリノの検出を計画している。このシンチレータにウラン系列核種 , トリウム系列核種 , 40K 等の天然放射性核種が存在すると，これらのβ壊変によりニュートリノが放出され、原子炉ニュートリノ検出の大きな妨げとなる。従って、シンチレータ中の放射性不純物の特定とその低減は，プロジェクトを成功に導くための非常に重要な課題である。
液体シンチレータには Gd を含む化合物を溶解させるが，その化合物合成のための原料の一つは酸化ガドリニウムである。希土類元素であるこの試薬には，天然アクチノイド元素である U と Th，ならびに環境中に多量に存在する K（40K）が不純物として混入している恐れがある。これまでに，U 濃度と Th 濃度は高感度機器分析法の一つである ICP 質量分析法により定量した。しかし，ICP 質量分析法では，K の定量は難しい。そこで，放射化分析法により酸化ガドリニウム中の K 濃度の定量を行った。
高感度で高確度な定量値を得ることができる放射化分析法は、微量元素に対する有用な定量分析法である。
一般に，中性子放射化分析法（NAA）がよく利用されるが，Gd は中性子捕獲断面積が非常に大きいため，照射中の中性子の自己吸収を無視することができず，正確な定量には比較標準試料の調製を注意深く行う必要がある。一方、試料に制動放射線を照射する光量子放射化分析法（PAA）で利用する（γ, n）反応の反44
応断面積は標的核種の質量数により系統的に変化し，特定の核種（元素）で共鳴的に大きな断面積を示すことがない。そのため，試料による自己吸収は起こりにくく，本試料においては NAA よりも正確な定量が可能だと考えられるため，PAA による K の定量を行った。しかし，K の定量に用いる 38K の半減期が7.6分と短い点で分析上の制約を受ける。

§２．実

験

純度99.999% の Gd2O3約600mg を Al 箔に包み，直径10mm の円板状に整形した。また，比較標準試料である K2CO3も同様に調製した。この2種類の試料を交互に石英管につめ，最大エネルギー25 MeV の制動放射線を10分間照射した。
（γ, n）反応で生成した 159Gd（半減期18.5時間）
当初は，照射後，非破壊測定による定量を試みたが，160Gdの放射能が強く，検出器に近づけて測定できなかったため，K の上限値しかえられなかった。そこで，次のような化学分離を迅速に行った。照射後，Al 箔から Gd2O3のみ取り出し，あらかじめ既知量の K+ 担体（約10mgK）を加え加熱しておいた6M 硝酸に溶解した。この溶液にアンモニア水を添加して水酸化ガドリニ
ウムを沈殿させた。遠心分離により分離した上澄み液を，さらに，孔径0.2μm のフィルターでろ過して，水酸化ガドリニウム沈殿を完全に除去した。この溶液を試薬瓶に移し，Ge 半導体検出器にてガンマ線を測定した。K2CO3は水に溶解後，Gd2O3試料と同様な形状にそろえ，ガンマ線を測定した。K の化学収率は再放射化法により求めた。測定対象である K 同位体を第１表にまとめた。
第１表

定量にもちいた K 同位体の核データ。

核種

半減期

ガンマ線エネルギー

K
K

7.6分
12時間

2167keV1525keV

38
42

39
41

K（γ, n）
K（ n, γ），再放射化法§３．結果と考察
異なる照射で定量を２回（試料 A と試料 B）行った。化学分離は約15分で終了し，化学収率はそれぞれ30% と51% であった。高い化学収率よりも短時間での化学分離を目指したため，水酸化ガドリニウムの精製を行わなかったのが低い化学収率の原因であろう。
第１図に試料 B での照射終了23分後のガンマ線スペクトルを示す。化学分離操作によりガンマ線測定の妨害となる 159Gd はほとんど除去できた。また，38K が放出するガンマ線のエネルギーは，（γ, n）反応で生成する核種から放出されるガンマ線のエネルギーの中ではもっとも高エネルギーなものの一つであることも幸いし，そのエネルギー領域ではコンプトン散乱によるバックグラウンドがほとんど０の状態で測定を行う
ことができた。試料 A でも同様であった。
38

K のガンマ線を検出できず，さらにバックグラウンドも０であったので，１カウント検出できた時の濃度を上限値として算出した。試料 A と B でそれぞれ，0.6ppm と0.1ppm となった。試料 B の方が分析条件がよかったので，Gd2O3試料中の K 濃度は0.1ppm 以下と決定した。よって，本研究で分析に供した Gd2O3
試薬は KASKA 実験で要求される K 濃度（１ppm）を十分満たしていることが確認できた。
ここでは詳細を省略するが，NAA による定量も行った。日本原子力研究開発機構 JRR4の簡易照射筒にて６時間照射し，放射化学分離後ガンマ線を測定した。上限値として0.9ppm を得た。NAA では試料の自己吸収により中性子束が見かけ上約1/10になることを別の実験より確認しており，これが PAA の方が NAA よ45

第１図 放射化学分離によるカリウムフラクションのガンマ線スペクトル。照射終了23分
後から300秒間測定。
りも低い上限値を得ることができた理由と考えられる。中性子吸収断面積が大きな元素で構成されるマトリックスを持つ試料の場合は，PAA が非常に有効であることを示している。

§４．ま と め
高純度酸化ガドリニウム試薬中のカリウム濃度を光量子放射化分析法により調べた。カリウムの上限値として0.1ppm を得た。KASKA プロジェクトで要求される条件を十分満たしていることを確認できた。

謝

辞

本研究を行うにあたり良質な電子ビームを供給していただいた東北大学原子核理学研究施設マシングルー
プの方々と試料照射ならびに放射線測定でお世話になった大槻勤助教授と結城秀行博士に深く感謝する。

参
[1]

考

文

献

M. Kuze and the KASKA Collabolation: Nucl. Phys. B149（2005）160.

核理研研究報告

第39巻

2006

47

(LNS Experiment : #2517, #2529, #2545, #2559, #2573)

加熱回収法によるコンクリート試料中放射性炭素分離法の検討
泉雄一 1，安藤佳明 1，松村一博 1，大槻勤 2，結城秀行 2，桝本和義 3
叙日本環境調査研究所（342-0008 吉川市旭 8-3）
東北大学理学部附属原子核理学研究施設（982-0826 仙台市太白区三神峯 1-12-1）
3
高エネルギー加速器研究機構（305-0801 茨城県つくば市大穂 1-1）
1

2

Separation Methods of Radioactive Carbon from Concrete Samples
by Thermal Combustion Methods
Y. Izumi1, Y. Ando1, K. Matsumura1, T. Ohtsuki2, H. Yuki2, K. Masumoto3
1

2

Japan Environment Research Co., Ltd, Asahi8-3, Ysoshikawa, Saitama, 342-0008
Laboratory of Nuclear Science, Tohoku University, Mikamine, Taihaku-ku, Sendai, Miyagi, 982-0826
3High Energy Accelerator Research Organization, Oho1-1, Tukuba, Ibaraki, 305-0801

In order to determine the activity of 14C induced in the concrete obtained from various accelerator
facilities, we studied the oxidative combustion method for extraction of 14C from concrete samples
quantitatively. Separation conditions, such as maximum heating temperature and time were examinedusing 11C produced by the 12C（γ,n）11C reaction as a radioactive tracer instead of 14C. Samples were
irradiated with 30MeV-bremsstrahlung at Laboratory of Nuclear Science, Tohoku University.
In this study, several types of standard rocks were combusted, because the thermal decompositionof such rocks contained in a concrete might be difﬁcult. After irradiation, samples were heated in an IRfurnace under O2 stream (flow rate ; 100ml/min). After the decomposition of sample, the gas wassequentially guided to another furnace (catalyst ; CuO, temperature ; 1073K) for oxidation of CO to
CO2. Radioactive carbon dioxide was collected in 2-amino-ethanol solution of an alkali trap.
As a result, the addition of oxidants was effective to improve 11C yields and yields of 11C fromstandard rock samples were over than 70% heated at 1373K for 20 minutes. It was concluded that theyields of 14C from concrete samples were also more than 70%. In case of steel samples, yields of 11C wereabout 100%.
It was concluded that the separation by the thermal combustion method was useful to separate
radioactive carbon, such as 11C and 14C, from concrete samples.

§１．目

的

加速器施設の遮蔽体として用いられているコンクリート中には微量ではあるが，加速器から二次的に発生する中性子による放射化によって様々な核種が生成することが知られている。これらのコンクリート中の放48
射性核種の濃度を評価する方法を確立しておくことが，施設を廃止する際に発生する廃棄物のクリアランス
レベルの検討にとって非常に重要である。筆者らは放射化によってコンクリート中に生成する核種のうち，測定が難しいとされている低エネルギーのβ線のみを放出する核種の放射能測定法を検討してきた。3H については濃度を測定する手順について検討し，コンクリート試料を加熱した後，酸化銅を用いた酸化触媒を通して，ドライアイスとエタノールによるコールドトラップで回収する方法を採用し，試料を900℃程度に加熱することによって定量できることを報告した［1］。また，加熱温度と時間を正確に制御できる赤外線加熱炉により，コンクリート試料中のトリチウム濃度を効率的に測定できることを報告した［2］。一方，放射化コンクリート中の 14C の放射能を測定するには 14C の分離法の確立が不可欠であるが，これまで定量例はほとんど無かった［3］。最近，遠藤らは，コンクリート中の 3H と 14C の定量を行った結果を報告した［4］が，２核種を２- アミノエタノールに捕集して液体シンチレーションカウンタで同時に測定している。しかし，この同時測定では，3H の濃度が高い場合に 14C の計数領域への 3H のテール成分の流れ込みの影響がある可能性があることも想定される。
コンクリート中の 14C の分離定量法を検討する際に，単に 14C を含む溶液をコンクリート中に浸透させるなどして調製した試料を用いたとしても，浸透させた 14C は放射化で生成した 14C と同様の挙動を示す保証はない。親核の存在量や反応断面積を考慮すると，14C は主に 14N の（n , p）反応によって生成すると予想される。このため，窒素濃度既知のコンクリートを中性子放射化すれば 14C 濃度既知のコンクリート試料が調整できると考えられるが，窒素は大気中に多量に含まれることから，正確に一定量の窒素を含むコンクリー
ト標準試料の調製は困難である。
炭素の放射性同位体としては 14C の他に 11C がある。そこで，コンクリートから 14C を定量的に回収できたかどうかを評価するかわりに，炭素濃度既知の試料を放射化し，生成した 11C をトレーサーとして用いることにより，放射性炭素の分離挙動を調べることができると考えられる。
すでに，非鉄金属や鉄鋼試料中の微量炭素の光量子放射化分析では，11C を酸素気流中で加熱分解し炭酸ガスとして分離捕集する方法を利用している［5］ことから，本研究では放射化した試料を用いて，赤外炉による加熱分離法での加熱温度や加熱時間等を変化させ，放射性炭素の分離条件を検討した。なお，ここでは比較的分解しにくいと思われる骨材として使用されている岩石試料を中心に検討することとした。

§２．試験方法
コンクリート試料を加熱し，14C を二酸化炭素として回収して 14C 濃度を測定するためには，測定試料を加熱するときの温度，維持時間等の諸条件の設定及び 14C の回収率の評価が必要である。
今回の試験では炭素濃度が既知の試料として地質調査所（現在，（独）産業技術総合研究所）より供給されている岩石試料（JA-１，JB-１a，JG-１a 及び JR-１の４種）及び（社）日本鉄鋼連盟より入手した鉄鋼試料（炭素濃度39ppm 及び1860ppm の２種）を東北大核理研電子ライナックで30MeV の制動放射線を照11
C 反応により生成させた 11C をトレーサーとして利用した。
射し，12C（γ, ｎ）

2.1

試料の照射

岩石試料及び鉄鋼試料は秤量して高純度アルミ箔に包んだ後，直径約10mm のペレット状に整形した。
さらに，試料の前後を Cu 箔で挟み，さらにアルミ箔で包み込んで照射試料とした。岩石等の試料重量は200mg から300mg とし，照射量補正のための標準物質（CaCO3）は約30mg とした。試料の照射条件は加速エネルギー30MeV，加速電流100μA，パルス幅3μsec，繰り返し数300pps とし，照射時間は原則とし

49て20分とした。

2.2 γ線照射量の補正
照射位置や加速条件の変動による各照射試料の照射線量の補正は，試料の前後に取り付けた Cu 箔中に生成した 61Cu または 64Cu の放射能を Ge 検出器により測定して行った。
2.3

加熱回収装置

第１図に加熱回収装置の装置構成を示す。照射した試料から回収した岩石等の試料を秤量した後，石英製のガラスボートに乗せ ULVAC 社製赤外炉により酸素気流中で加熱した。赤外炉による試料の加熱パターンの例を第２図に示す。このときの酸素流量は100ml ／分である。試料は加熱開始後５分間で1000℃に，その後５分間で最大温度である1100℃に達するように設定した。最大温度保持時間を５分間とし，加熱開始
後15分後に加熱を終了し，20分経過するまで回収した。
炭素の酸化を完全にするため，赤外炉の後段には800℃に設定した酸化銅を用いた酸化触媒用電気炉を接続し，ドライアイス・アルコールを用いたコールドトラップの後に，２- アミノエタノールによる 11C 回収用のアルカリトラップを接続した。

第１図

第２図

Apparatus for Heating Samples by IR-Furnace.

Heating Pattern of Samples by IR-Furnace.

50
2.4

酸化剤の添加照射した試料の分解・酸化を促進するために，四三酸化鉛と酸化硼素の１：１混合物を１ｇまたは LECO
社製 Sn 系の酸化剤を２ｇ添加した。
2.5

13

N の分離

試料の照射によって 11C と同時に生成する陽電子放出核種として半減期10分の 13N がある。試料を加熱した際に，13N が窒素酸化物になると，炭酸ガスと同時に捕集されることになる。この両者を分離するには半減期の違いを用いることも可能であるが，ここでは，13N は酸化コバルトをシリカゲル中に分散させた吸着剤（以下，酸化コバルト－シリカゲル）を入れたカラムをアルカリトラップの前に挿入して捕集することにした。酸化コバルト－シリカゲルは硝酸コバルト飽和水溶液とオルトケイ酸エチルをかくはん，混合しゲル化させた後，電子レンジで加熱し，加水分解の結果生成したエタノールおよび水を蒸発させ，さらに電気炉
中400℃で２時間乾燥したものを用いた。

2.6

11

C 測定方法及び 11 C 回収率

２- アミノエタノール２ml を用いたアルカリトラップに回収した 11C は BGO 検出器を用いた同時計数回路を用いて測定し，加熱終了後５分間計数率が上昇せず回収が終了したことを確認した。
回収が終了したアルカリトラップ中の２- アミノエタノールはメタノール16ml を用いてトラップ管を洗浄して回収した。洗浄液を含めて全量をバイアルに回収し，NaI（Tl）検出器を用いて同時計数率の時系列変化を測定した。得られた計数率は全て照射終了時点に減衰補正した。
11

C 生成効率は標準物質として CaCO3を照射したときの 11C 生成量を基準として求めた。これにより求めた照射試料に生成した 11C 量から岩石試料等の炭素濃度を算出し，各岩石試料等の標準炭素濃度と比較する
ことにより，加熱回収法による 11C 回収率を求めた。

§３．試験結果
3.1

酸化剤による分解

コンクリート試料に酸化剤を添加したときの 11C の回収率を第１表に示す。これにより，酸化剤を添加しない場合は60％程度の回収率であったが，酸化剤特に Sn 系酸化剤を添加することにより 11C の回収率が向上することが確認された。以下の測定では全て Sn 系酸化剤を用いた。
第１表
Sample
JA-1
JB-1a

3.2

13

Effect of Oxdants Addition to 11C Yields.
Oxidants

Yield of carbon (%)

No Addition
Pb3O4 ＋ B2O3
Sn Oxidants
No Addition
Pb3O4 ＋ B2O3
Sn Oxidants

57.8
71.9
111.6
60.7
63.3
73.7

N の分離

第３図に 11C を回収したアルカリトラップ試料と 13N を吸着させたカラムから取り出した酸化コバルト－
シリカゲルの NaI（Tl）検出器による計数率の時間変化を示す。これにより，アルカリトラップ試料では半51
減期20.4分のみの減衰が，酸化コバルト－シリカゲル試料では半減期9.97分のみの減衰が確認された。これにより，酸化コバルト－シリカゲルにより 13N が回収されており，11C の測定に 13N の影響を排除できることが分かった。

第３図
3.3
11

Separation of 13N and 11C by Adsorption Column.

アルカリトラップ段数

C を回収するときに必要なアルカリトラップ段数を確認するため，複数のトラップを取り付けたときの回収率を求めた。この結果，２段目以降のアルカリトラップの計数率は，１段目に比較して1/1000以下であった。よって，アルカリトラップは１段で十分回収できることが分かった。なお，斉藤らは炭素量として約40mg 程度までアルカリトラップによりほぼ定量的に回収できることを報告している［5 ］。これに対し，今回加熱回収した試料の炭素量は最大でも鉄鋼試料の0.6mg であり，十分低い炭素量となっている。

第４図
3.4

Counts of 11C by BGO-Detector.

岩石試料等の 11 C 回収率

第４図に加熱経過時間と BGO 検出器の計数率変化の例を岩石試料 JA-１について示す。加熱開始後ほぼ５分経過した時点から計数率が上昇したのち，８分前後で急激に上昇し，約12分後に計数率の上昇は終了
する。
加熱する試料の位置が加熱用ガラス管（内径30mm，長さ500mm）の中央にあるとし，試料からアルカ52
リトラップまでの回収経路の体積を求めると約440cm3 である。11Cが酸素供給でのみ移動すると仮定すれば，
11C が試料から放出されてからアルカリトラップに到達するまでに約4分必要である。よって，最も 11C が放出される温度は第２図に示す加熱パターンから赤外炉の設定温度は800℃前後と推定される。ただし，実際の試料温度は酸化剤の添加によりさらに高い温度となっている可能性がある。また，第４図に示した計数率の変化量によれば加熱開始後20分経過すれば 11C は十分回収できているものと考えてよい。
第２表に各種の試料を用いて得られた 11C の回収率を示す。この結果，炭素濃度が70.8ppm から312ppmの範囲の岩石試料では試料によって多少異なるものの 11C の回収率はほぼ70％以上であった。また，鉄鋼試料ではほぼ定量的に回収できることが分かった。
第２表
Sample
JA-1
JB-1a
JG-1a
JR-1
Carbon Steel-1
Carbon Steel-2

Yields of Carbon.

CarbonConcentrations
(ppm)
271.0
312.0
295.0
70.8
39.0
1860.0Maesured(ppm)

Yields ofcarbon (%)

196.7
233.3
257.3
51.7
42.7
1822.4

72.6
74.8
87.2
73.0
109.5
98.0

前述のように NaI（Tl）検出器による 13N 吸着カラムの測定結果では 11C は確認されなかった。また，標準物質を乗せた石英ガラスボートでも 11C が残存していないことを確認した。しかし，岩石試料を加熱した
石英ガラスボートの測定結果では計数率が高いものの，種々の核種が生成しているため，半減期を考慮した
11

C 成分の分離によってその残存量を定量することは困難であった。岩石試料で 11C の回収率が低い理由は明らかではないが，加熱後の試料に残存している可能性もあると推定される。
以上のように岩石試料で若干回収率が低かったものの，今回用いた赤外炉による放射性炭素の加熱回収
法では安全管理上は十分な回収率が得られた。
コンクリート中または空気中の窒素が中性子照射されることにより生成する 14C は CO2を経由してコンクリート中に含まれると仮定すると，コンクリートの中性化により生じる CaCO3は骨材としての岩石より熱分解が容易であることから，実際のコンクリート試料ではさらに回収率が高くなると思われる。

§４．ま と め
コンクリート試料中の 14C 濃度評価のモデルとして，12C（γ, ｎ）により生成させた 11C を用い，鉄鋼試料
及びコンクリート組成のうち加熱分解しにくいと思われる骨材用の岩石試料について加熱回収法による回収率を求めた。この結果，最大加熱温度1100℃，加熱時間合計20分で70％以上の回収率が得られた。よって，
14

C についても岩石試料ではほぼ同様の回収率が得られるものと考えられる。実際のコンクリートでは骨材である岩石以外に，熱分解の容易な CaCO3の成分があるため，14C の回収率はさらに高いものと考えてよい。
以上から，コンクリート試料中の放射性炭素濃度測定には加熱回収法による分離回収が有効であることが
分かった。

53

参

考

文

献

[1]

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[2]

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[4]

A. Endo, Y. Harada, K. Kawasaki, M. Kikuchi: Int. J. Appl. Radiat. and Isotopes 60（2004）955.

[5]

K. Masumoto, K. Shikano, T. Ohtsuki, Y. Itoh: Anal. Sci. 17（suppl.）（2001）641.

[6]

斉藤智雄他 : Radioisotopes 25（1976）36.

Ⅲ．Accelerator, Synchrotron Radiation,and Instrumentation

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

55(LNS Experiment : #2537, #2553)

Properties of the Coherent Radiation Emitted from
Photonic Crystal in the Millimeter Wave Region. Ⅰ
Y. Shibata1, K. Ishi1, T. Tsutaya1, N. Horiuchi2, Y. Segawa2, Y. Kondo3, H. Miyazaki3,
F. Hinode4, T. Ochiai5, and K. Ohtaka6
1

2

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University,
Katahira, Sendai 980-8577

Photodynamics Research Center, The Institute of Physical and Chemical Research (RIKEN),
3

Sendai 980-0845
Graduate School of Engineering, Tohoku University, Aramaki, Sendai 980-8579

4

Laboratory of Nuclear Science, Tohoku University, Mikamine, Sendai 982-0826
5
Nanomaterials Laboratory, National Institute for Materials Science (NIMS),
Tsukuba 305-0044
6
Center for Frontier Science, Chiba University, Chiba 263-8522

Using a short-bunched beam of electrons of a linear accelerator, sharp directionality of the coherent
radiation emitted from a photonic crystal (PhC) was observed in the millimeter wave region. When the
PhC was rotated around an axis perpendicular to the surface of the PhC, the radiation intensity
decreased drastically. On the other hand, the dispersion relation of the radiation changed little with therotation. The decrease of the intensity was conspicuous in the high frequency region, in comparison
with that of the low frequency region.

§1. Introduction
When a short-bunched beam of electrons from a linear accelerator passes by near the surface of aphotonic crystal (PhC), coherent radiation is emitted in the millimeter wavelength region [1]. In thispaper we call it the photonic crystal radiation. The origin of the photonic crystal radiation is consideredin essence to be the same as that of Smith-Purcell radiation (SPR), which was emitted from the electron
passing by a metallic grating [2]. Contrary to the many researches on SPR, the experimental study on
the photonic crystal radiation has been limited, and its optical properties have been not well studied.
For example, the photonic crystal radiation is considered to satisfy the dispersion relation of SPR; therelation bases on a kinetic relation between the period of the radiation source, the frequency of theradiation and the velocity of the electron. In our experiment using an S-band linear accelerator,
however, the observed dispersion relation of the photonic crystal radiation was composed of two groups:
the one satisﬁed the dispersion relation of SPR and the other obeyed another relation clearly different
from the SPR relation [1, 3]. The unexpected dispersion relation has excited a controversy over its
origin.
To elucidate the properties of photonic crystal radiation, here, we report an experiment in which

56
PhC was rotated around an vertical axis. The experiment showed sharp directionality of the photonic
crystal radiation.

§2. Brief Summary of Photonic Crystal Radiation
Let us summarize the mechanism of the photonic crystal radiation briefly [4, 5]. We used thecoordinate system shown in Fig. 1, and let an electron move with constant velocity υ along the x axis.
We take the coulomb field of the moving electron as a source of virtual radiation. The Fouriercomponent of the radiation ω has a wave vector (kx, ky, ±Γ ), with the x component given by kx = ω / υand the y component ky is arbitrary. By energy conservation, Γ =√(ω / c )2 － kx2 － ky2 . Since υ＜c, Γ is pure
imaginary, meaning that the radiation is evanescent and decays with constant |Γ | with distance fromthe trajectory of the electron. In other words, the line ω = υkx, called the υ line, lies outside the lightline ω = ckx.
When the evanescent wave reaches to a PhC, the photonic crystal radiation is emitted through theelectromagnetic interaction between the incident radiation and the PhC. When we observe far-fieldradiation within the xz plane, ky can be set to zero. The PhC having a period g in the x direction thenproduces the photonic crystal radiation by giving a Umklapp change of the integer multiple of 2 π /g tothe x component of the wave vector of incident light. Using the same symbol kx to represent the xcomponent of the photonic crystal radiation, we may say that the incident radiation on the υ line is
Umklapp-shifted to the new υ lines of dispersion ω = υ(kx ＋ n(2π/g)), n being an arbitrary integer. We
shall call these lines υn lines. The light on the υn line thus has the z component of the wave vector given
by

Γn =

√( ωc ) − (υω ) − n (2πg ) .
2

2

2

敢

It reaches a far-ﬁeld observation point as the photonic crystal radiation when this Γ n is real, i.e., when
the frequency ω of the radiation on the υn line is inside the light cone. This can always happen for a υnline with positive n.
In the PhC, photonic band modes have their band structure in (kx, ω) space. When υn line crosses a
photonic band dispersion curve, corresponding peaks appear in the spectrum of photonic crystal
radiation [1, 4, 5]. The photonic crystal radiation hence is considered to be distributed along the υnlines in the (kx, ω) diagram.
The υn line is equivalent to the dispersion relation of SPR given byn λ= g(υω − cos θ) ,柑

where λstands for wavelength and θ for emission angle of the photonic crystal radiation.

§3. Experiment
The experimental setup is schematically shown in Fig.1. A short-bunched beam of electrons of a57
linear accelerator of Laboratory of Nuclear Science (LNS), Tohoku University moved with constantvelocity υ along the x axis above a PhC. The radiation emitted from the PhC was observed in the xz
plane, and the emission angle θ was measured from the x direction.
The photonic crystal radiation was guided to a Martin-Puplett type Fourier-transform spectrometer
and was detected with a low-temperature InSb detector. The resolution of the spectrometer was 0.125
cm − 1 or 3.75 GHz. The plane mirror M1 was controlled with a stepping motor to cover the emission
angle θ between 60°and 120°, keeping the optical axis unaltered. The acceptance angle of themeasuring system depended a little on the angle θ and was ± 0.75°in the xy plane and ± 1.2°in the yz
plane at θ = 90°. The impact parameter or the distance between the electron beam and the surface of
the PhC was set to be 10 mm.
The beam condition was as followings. The energy of the electron was 150 MeV and its spread wasless than 2.5 %, the macro and micro pulse widths were 1.5 μs and 0.67 ps, respectively. The repetitionof the macro pulse was 50/3 Hz and the average beam current was 0.8μA. The cross section of the beam
was nearly circular and about 10 mm in diameter.
As the PhC we prepared two samples: a monolayer of spheres of polytetraﬂuoroethylene (PTFE) andthat of cylinders of PTFE (see Fig.1 (b)). Every sphere was 3 mm in diameter, and 419 spheres werearrayed to a triangular lattice on a plane parallel to the xz plane; the size of the monolayer was about
48 mm × 71 mm in the y × x direction. The reciprocal lattice space of the triangular lattice is shown in
Fig. 1 (b) of [1]. In the case of the cylinder, every cylinder had the size of φ 3 mm × 80 mm in diameter× length and was placed so that the cylinder axis was parallel to the y direction; the PhC was periodic
in the x direction and the number of cylinders was 27.
The PhC was controlled with a stepping motor to rotate around the vertical axis (parallel to the zaxis) at the geometric center of the monolayer. The rotation angle φ was measured counter-clockwisefrom the x direction.

Fig.1. Schematic layout of the experiment (a) and of the drawing of the photonic crystals used (b).
The electron orbit was shown by the thick solid line. The emission angle θ and the rotation
angle φof the PhC were measured from the x direction.

58§4. Results and Discussion
4.1 Triangular lattice of PTFE spheres
At first to check the measuring system, we observed emission spectra of the photonic crystal
radiation from the monolayer of the PTFE spheres by varying the rotation angle φ. Figure 2 shows the
spectra observed at φ = 0°, ± 1°and ± 3°, on the condition of the emission angle θ = 90°. Eevery
spectrum was composed of several peaks, and its structure was nearly symmetric with respect to φ = 0°.
The radiation intensity varied drastically with the rotation angle φ.

Fig.2. The spectra of the PTFE spheres observed with the rotation angle φ = 0°, ± 1°and ± 3°
for the emission angle θ = 90°. The dotted curves show the spectra with the negative φ.
The spectra at φ= 0°and ± 1°were shifted vertically to make the comparison clear.
Next the rotation angle φ was set to 0°, and the emission spectra were measured with thespectrometer, by controlling θ from 70°to 110°by 1°step. From the spectrum, using the relation kx =( ω / c) cos θ, we obtained the contour map of the intensity of the photonic crystal radiation in the (kx, ω)
space. The result is shown in Fig.3; the abscissa stands for the normalized wave vector Kx = kxg / (2π)
and the ordinate for the frequency of photonic crystal radiation ν = ω/(2π) in GHz. In Fig.3, using therelation k = ω / c = 2π/ λ and v = c β, the dispersion relation of Eq. (2) is expressed by the following
straight line;cβ
ν= g (Kx ＋ n).

桓

Since the energy of the electron was 150 MeV, the relativistic factor γ= 297 and β = υ/ c = 0.999994.
We can safely put β = 1, and hence the dispersion line υn is parallel to the light line in the (kx, ω)diagram. The intensity map clearly showed two series of dispersion relation. One is the dispersion
relation of SPR shown by the solid lines. The other is the unexpected one shown by the broken lines,
whose gradient is 78 % of the solid line. We call hereafter its relation the secondary dispersion relation.
The origin of the secondary relation has been clarified by Horiuchi et al. [3]. In both relations, thefundamental and the second higher harmonic relations were clearly seen in the ﬁgure.

59

Fig.3. The contour map of the photonic crystal radiation from the PTFE spheres in the (kx, ω) plane
observed with the rotation angle φ = 0°. The x and y axes are the normalized wave vector
Kx and the frequency of the radiation, respectively. The solid lines show the υ1, υ2, υ3 andυ4 lines from bottom to upward.
Using the period of the PhC of g = √3 d / 2, we calculated the theoretical dispersion relation of SPR, i.e,the υn line,cν= g (Kx ＋ n),

棺

where ν is frequency, Kx is the normalized wave vector and n is integer, i.e, the order of the relation.
However, the calculated relation with the diameter of the PTFE sphere d of 3.0 mm deviated a little
from the experimental intensity map. To fit the experiment, we adopted the value d = 3.2 mm. The
calculated relation is shown in the ﬁgure by the solid lines. The precision of the diameter of the PTFE
sphere was better than 0.01 mm, and the reason of the deviation is not clear at present. In the ﬁgure,the broken lines show the eye-ﬁtted mean of the secondary dispersion relation expressed byc
ν= α g (Kx ＋ n),款with d = 3.2 mm and α= 0.78. We call these lines the un lines.
On the υ1 line, the distribution of the radiation intensity was plotted as a function of frequency by
the solid curve in Fig.4, where the broken curve shows the distribution of the intensity along the u1 line.
Along each of these dispersion relations, the radiation intensity varied rapidly with frequency.
The emission spectra were also measured at the rotation angles φ= 2°, 4°and 8°, and Fig.5 showsthe (kx, ω) maps at φ = 2°and 4°. In the figure the solid lines show the υn lines calculated on thecondition of d = 3.2 mm and the gradient of the broken lines was 78 % of the υn line. At φ = 8°thephotonic crystal radiation was very weak and near to the noise level of the measuring system, so the60

Fig.4. The spectral distribution along the dispersion relation of the first order. The solid andbroken curves show the distribution following the SPR relation and the secondary one,respectively.

intensity map was not shown.
The comparison of Figs.3 and 5 shows the followings. The photonic crystal radiation was very
sensitive to the rotation angle φ. The radiation intensity decreased drastically with |φ|, and thedecrease was conspicuous in the high frequency region. Though the intensity change was drastically,both the dispersion relations suffered little inﬂuence from the rotation.

Fig.5. The contour maps of the photonic crystal radiation from the PTFE spheres in the (kx, ω)
plane at φ = 2°(a) and φ = 4°(b). The abscissa and ordinate show the normalized wave
vector Kx and frequency of the radiation. The solid and broken lines show the υn and unlines, respectively.

61
4.2 1D-lattice of PTFE cylinder
After the experiment on the PTFE spheres, photonic crystal radiation of the monolayer of the PTFE
cylinders was observed. However, the observed range of the emission angle θ was limited, because oflack of the experimental time.
Figure 6 shows the observed spectra at φ = 0°, ± 2°and ± 4°for the emission angle θ = 105°. The
structure of the spectra resembled that of the PTFE spheres; the structure was symmetric with respect
to the rotation angle φ = 0°. Figure 7 shows the spectra at φ = 0°and 2°with θ = 78°. The radiation
intensity decreased drastically with |φ|, too.
The (kx, ω) map was also derived from the observed spectra at the rotation angles φ = 0°, 1°, 2°
and 4°as shown in Figs.8(a), (b), (c) and (d), respectively. In the experiment, however, the observed

Fig.6. The spectra of the PTFE cylinders observed at the rotation angles φ= 0°, ± 2°and ±4°for
the emission angle θ= 105°. The dotted curves show the spectra with the negative φ .

Fig.7. The spectra of the PTFE cylinders observed at the rotation angles φ= 0°and 2° for θ= 78°.

62

Fig.8. The contour maps of the photonic crystal radiation from the PTFE cylinders in the (kx, ω)
plane at φ = 0°(a), 1°(b), 2°(c) and 4°(d). In each diagram, only the limited range of θ wasobserved. The abscissa is the normalized wave vector and ordinate is frequency of theradiation. The solid and broken lines show the υn and un lines, respectively, calculated on
the condition of g = 3.1 mm.
range of θ was limited between 110°and 100°and/or between 80°and 70°. In these ﬁgures, the solidlines stand for the υn lines, calculated using the period of g = 3.1 mm. Since the precision of thediameter of the PTFE cylinder was much better than 0.1 mm, the reason of the difference between the
diameter (3.0 mm) and the period (3.1 mm) is not clear. The difference may be partly caused from small
errors in the straightness of the cylinder.
Though the measurement was limited to the narrow ranges of θ, the intensity map had the similar
characteristics to that of the PTFE spheres. The photonic crystal radiation had two series of thedispersion relation; one is that of SPR corresponding to the solid lines and the other is a series of thesecondary dispersion relation, corresponding to the broken lines whose gradient was 74 % of the υn line.
The gradient was roughly equal to that of the PTFE spheres.
The radiation intensity decreased drastically with the rotation angle |φ| and the decrease wasconspicuous in the high frequency region. Though the intensity decrease was drastic, it seemed thatboth the gradient of the υn and un lines suffered no inﬂuence from the rotation.

63
4.3 Simple discussion on dispersion relation
Here we simply consider the phase relation of the photonic crystal radiation emitted fromneighboring two unit crystals of a PhC on the basis of Huygens' principle. Let an electron move with theconstant velocity υ= c βalong the x axis and the period of the PhC be g. Let's suppose that the Coulomb
ﬁeld of the moving electron or the evanescent wave excites radiation in every unit crystal and that at
an observation point the superposition of the radiation from neighboring unit crystals should satisfy theconstructive interference condition,nλ = c Δ t − g cos θ ,歓where λ is the wavelength of the radiation and Δ t = g / c β is the time interval of the electron to movethe period of PhC. The dispersion relation of SPR, Eq.(2), is directly derived from the condition. The
dispersion relation is caused from the kinetic relation of phase matching among the period, electron
velocity, emission angle and wavelength of radiation. The relation is irrelevant to the dielectric constantof constituent of the PhC.
Next, let's suppose that part of radiation (say radiation "a") excited by the electron propagates tothe downstream neighboring unit crystal and generates new radiation (radiation "b") which is emitted
into free space. From the superposition of radiation "a", directly emitted into free space, and radiation"b", we can derive the similar interference condition,nλ = c δt − g cos θ ,汗where δt is propagation time of radiation to the neighboring unit crystal. Using the effective dielectricε/ c. Then the condition becomes
constant ε of the PhC, we assume δt = g √ε − cos θ ).
nλ = g (√漢In the (kx, ω) diagram, the condition is expressed asν=c(Kx ＋ n),g√ε澗where Kx is the x component of the normalized wave vector. The condition is equal to the secondary
ε. In the experiment, the value of α derived
dispersion relation of Eq.(5), on the condition that α = 1/√
from the PTFE sphere was a little larger than that of cylinder; it is consistent with the above
consideration.
The above discussion is based on that radiation emitted from the unit crystal is composed ofradiation directly generated from the electron and of response to incident radiation generated in the
upstream unit crystals. Since the incident radiation is composed of a pulse train of radiation generated
in the nearest neighbor upstream unit crystal, radiation in the second nearest one and so on, at theobservation point the radiation from the unit crystal may be formally written by

64

Er = { A ＋ Be iΔφ [1 ＋ reiΔφ ＋ r2ei2Δφ ＋…]} exp ( i (kx −ω t)),潅where A and B are the amplitude of radiation directly generated by the electron and that of the
response to radiation generated in the nearest neighbor upstream unit crystal, respectively. The phasedifference between radiation "a" and "b" is expressed by Δ φ, using the propagation time δt,(

Δ φ = k Δ x −ωδ t = g kx −

)

ω√
ε
,
c

環

and r is a damping factor of amplitude in propagation per unit crystal.
The total radiation from every unit crystal is written byiΔφ( A ＋ 1−Bere ) exp ( i (kx −ω t)) (1 ＋ e ＋ e ＋…)
Be
exp ( i (kx −ω t))= (A＋,1− re )
1− e

Et =

iΔφ

iΔφ

i 2Δφ

iΔφ

iΔφ

iΔφ

甘

where Δφ is the phase difference of radiation between neighboring crystals,(

Δφ = k Δ x －ωΔ t = g kx −

ω
βc

).

監

The intensity becomes|Et|2 =(A2 ＋

B2 ＋2 AB (cos Δφ − r)
1
φ .
2
1＋ r −2 rcos Δφ4 sin2( Δ
−
2 )

)

看

The radiation peak appears when the following condition is satisﬁed:
Δφ
= nπ.
2

竿

The dispersion relation of SPR is directly reduced from this condition. In addition, the second term ofEq.(12) is similar to the radiation from a Fabry-Perot resonator and shows also oscillating
characteristic. Its peaks appear under the condition,Δφ = 2 nπ.

管

The condition is corresponding to the secondary dispersion relation. Hence we can take the relation as
the new resonant dispersion relation. When the peak condition of Eq.(16) is fulﬁlled, the intensity isgiven by

65

|Et|2 =

2

( A ＋ 21＋ABr ＋ (1＋B r) ) 4 sin1 ( −) .
2

2

2 Δφ
2

簡

These equations show that the radiation intensity along the SPR dispersion relation deﬁned by Eq.
(15) will be much higher than the radiation emitted under the condition of Eq.(16). On the other hand,Eq.(16) is not sufﬁcient condition for the secondary dispersion relation. When the damping factor r issmall or far from unity, the radiation peak will be vague, supposing that the condition is fulfilled.
However, if r is near to unity, the intensity will be high enough to show the new resonant dispersion
relation.
The above consideration shows that the dispersion relation of SPR is caused from the constructive
interference of radiation directly excited by the electron. On the other hand, the secondary dispersion
relation seems to originate from the interference between radiation directly excited by the electron andradiation indirectly generated in the upstream crystals.

Acknowledgement
We appreciate Professors J. Kawamura and T. Arima of IMRAM, Tohoku University for theirencouragement and support, and Professor emeritus K. Mizuno of Tohoku University for his kind
support to utilize the low temperature InSb detector. We also thank Messrs. T. Tsutaya, Y. Chiba of
IMRAM, the member of the optical group of Photodynamics Center, RIKEN, and the staff of LNS,
Tohoku University, for their help in the experiment. This work was supported by the Special
Coordination Funds for Promoting Science and Technology from the Ministry of Education, Culture,
Sports, Science, and Technology of Japan.

References[1]

K. Yamamoto, R. Sakakibara, S. Yano, Y. Segawa, Y. Shibata, K. Ishi, T. Ohsaka, T. Hara, Y.
Kondo, H. Miyazaki, F. Hinode, T. Matsuyama, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 69 (2004)
045601.

[2]

S. J. Smith and E. M. Purcell: Phys. Rev. 92 (1953) 1069.

[3]

N. Horiuchi, T. Ochiai, J. Inoue, Y. Segawa, Y. Shibata, K. Ishi, Y. Kondo, M. Kanbe, H. Miyazaki, F.
Hinode, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 74 (2006) 056601.

[4]

K. Ohtaka and S. Yamaguti: Opt. Spectrosc. 91 (2001) 477.

[5]

S. Yamaguti, J. Inoue, O. Haeberl , and K. Ohtaka: Phys. Rev. B 66 (2002) 95202.

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

67(LNS Experiment : #2537, #2553)

Properties of the Coherent Radiation Emitted from
Photonic Crystal in the Millimeter Wave Region. Ⅱ
Y. Shibata1, K. Ishi1, T. Tsutaya1, N. Horiuchi2, Y. Segawa2, Y. Kondo3, H. Miyazaki3,
F. Hinode4, T. Ochiai5, and K. Ohtaka6
1

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira,
2

Sendai 980-8577
Photodynamics Research Center, The Institute of Physical and Chemical Research

3(RIKEN), Sendai 980-0845
Graduate School of Engineering, Tohoku University, Aramaki, Sendai 980-8579

4

Laboratory of Nuclear Science, Tohoku University, Mikamine, Sendai 982-0826
5
Nanomaterials Laboratory, National Institute for Materials Science (NIMS),
Tsukuba 305-0044
6
Center for Frontier Science, Chiba University, Chiba 263-85226

Properties of coherent radiation emitted from a Photonic crystal (PhC) is studied by experimentsin the millimeter wave region, under various geometric arrangements of the PhC with respect to anelectron beam, such as (1) reﬂective arrangement, (2) refractive arrangement and (3) longitudinal shift.
In these arrangements, we observe not only the dispersion relation of Smith-Purcell radiation but also
another relation or the secondary relation. The inﬂuence of the arrangement on the coherent radiation
is mainly discussed in the (kx, ω) diagram.

§1. Introduction
When a short-bunched beam of electrons of a linear accelerator passes by near the surface of aphotonic crystal (PhC), coherent radiation is emitted in the millimeter wavelength region [1, 2]. In thispaper we call it the photonic crystal radiation. The origin of the radiation is in essence considered to be
the same as that of Smith-Purcell radiation (SPR), which is emitted from the electron passing by ametallic grating [3].
To elucidate the properties of photonic crystal radiation, we have made a series of experiments bychanging the geometrical arrangement of PhC to the electron beam. Following the previous report(refered to as paper I [4]), here we report the experiments on (1) the reflective or refractive
arrangement, (2) interference between photonic crystal radiation from the two arrangements and (3)longitudinal shift of PhC.
We adopted here the same technical terms in the paper I [4], where the background of the photonic
crystal radiation was brieﬂy described.

68§2. Reflective or Refractive Arrangements
2.1 Experiment
The experimental setup is schematically shown in Fig.1. In the case of (a), a short-bunched beam ofelectrons from the linear accelerator at Laboratory of Nuclear Science (LNS), Tohoku University moved
with constant velocity v along the x axis above a PhC. The photonic crystal radiation from the PhC wasobserved in the xz plane, and the emission angle θ was measured from the x direction. In the case (b)the PhC was placed above the trajectory of the electron beam; the position of the PhC was symmetric toExperimental
setup(LNSTU)
that of (a) with respect to the xy plane.
Hereafter wecall theset up (a)Fig.1
the reﬂective arrangement, and (b)the refractive arrangement.

(a)

M1’

M1

(b)

M1

M1’

spectrometer

spectrometer

�

z
x

�

e - beamhhe - beam

Photonic crystal
Fig.1.

Schematic layout of the experiment of reflective arrangement (a) and refractive
arrangement (b). The electron orbit was shown by the thick solid line. The emission angle
θ was measured from the x direction.

In both arrangement, the photonic crystal radiation was guided to a Martin-Puplett type Fouriertransform spectrometer and was detected with a low-temperature InSb detector. The resolution of thespectrometer was 0.125 cm－1 or 3.75 GHz. The plane mirror M1 was controlled its position anddirectionality with a stepping motor to cover the emission angle θ between 60° and 120°, keeping theoptical axis unaltered. The acceptance angle of the measuring system depended a little on the angle θ
and was ± 0.75° in the xz plane and ± 1.2° in the yz plane at θ ＝ 90°. The impact parameter or the
distance between the electron beam and the surface of the PhC was set to be 10 mm.
The beam condition was as followings. The energy of the electron was 150 MeV and its spread wasless than 2.5 %, the macro and micro pulse widths were roughly 1.5 μs and 0.67 ps, respectively. The
repetition of the macro pulse was 50/3 Hz and the average beam current was 0.9 μA. The cross sectionof the beam was nearly circular and about 10 mm in diameter. Since the energy of the electron was 150
MeV, the velocity of the electrons was v ＝ 0.999994 c.
As the PhC we prepared two samples used in paper I: a monolayer of polytetraﬂuoroethylene (PTFE)
spheres and that of arrayed cylinders of PTFE.

69
In the experiment, the emission spectrum of photonic crystal radiation was measured with thespectrometer, by controllingθfrom 60° to 115° by 1° step. From the spectrum, using the relation kx ＝ (ω/ c) cos θ, we obtained the contour map of the intensity of the photonic crystal radiation in the (kx, ω)diagram.
In the series of experiments, the measuring system and PhC used was common, and the accelerator
was carefully tuned to keep the same beam condition. Detail of the experiment including setup on theother arrangements is described in later.
2.2 Results and discussion
2.2.1 Radiation in reflecting arrangement
Using the reﬂective arrangement, we measured the photonic crystal radiation from the monolayerof the PTFE spheres with the spectrometer and derived the contour map of the intensity from thespectra. The result is shown in Fig. 2, where the abscissa is the x component of the normalized
wavevector Kx ＝ g kx /2 π ＝ g cos θ/λ with the period g and the ordinate is the frequency of radiation ν＝ ω / 2π in GHz.The solid lines show the theoretical dispersion relation of SPR calculated with thediameter of the sphere d of 3.2 mm, i.e., the υn lines given by Eq. (4) of the paper I [4] .
The observed (kx , ω) map had the same characteristics to those of paper I. The photonic crystal
radiation holds two dispersion relations; one is the relation of SPR and the other is the secondary
dispersion relation, not expected from a simple theory of the photonic crystal radiation. We can take therelation as the new resonant dispersion relation [4]. The new relation was calculated with Eq. (5) of theFig.2.

The contour map of the intensity of photonic crystal radiation from the PTFE spheres inthe (kx, ω) plane observed in the reﬂective arrangement. The abscissa and ordinate are thenormalized wave vector Kx and the frequency of the radiation, respectively. The solid andbroken lines show the vn and un lines, respectively, calculated for the diameter of the sphered ＝ 3.2 mm.

70
paper I on the condition that α ＝ 0.78 and is shown by the broken lines in Fig.2. Along both therelations with n ＝ 1, each radiation intensity varied sharply with the emission angle θ.
2.2.2 Radiation in refractive arrangement
The experimental setup was changed to the refractive arrangement, and the spectra of the photonic
radiation from the monolayer of the PTFE spheres were measured for the emission angle θ from 60° to115°. The obtained contour map is shown in Fig.3, where the υn and un lines are shown by the solid andbroken lines, respectively, calculated on the condition that d ＝ 3.18 mm and α ＝ 0.78. Ignoring thesmall difference in the ﬁtting parameter d, we consider that the υn and un lines in Fig.3. are the sameas those of Fig.2.
Figure 3 shows in general the same characteristics to those of the reﬂective arrangement shown in

Fig.3.

The contour map of the intensity of photonic crystal radiation from the PTFE spheres inthe (kx, ω) plane observed in the refractive arrangement. The solid and broken lines show
the vn and un lines, respectively, calculated for d = 3.18 mm.

Fig.2. The photonic crystal radiation in refractive arrangement also holds both the dispersion relations,
the SPR one and the new resonant relation. New features such as the new dispersion relation did notappear in the (kx, ω) diagram. However, the comparison of Figs.2 and 3 clearly shows a few differences
as following. The higher order dispersion relation of SPR is conspicuous in Fig.3. On the other hand, the
new resonant dispersion relation has no such feature. The photonic crystal radiation seems to be
suppressed in the low frequency region, that is to say, less than about 120 GHz or 4 cm － 1. The
suppression is common in both dispersion relations.
To confirm the features, we replaced the PhC from the monolayer of the PTFE spheres to themonolayer of the PTFE cylinders and measured its emission spectra. The contour map derived from thespectra is shown in Fig.4. The solid lines show the dispersion relation of SPR calculated for the
diameter of the cylinder d of 3.1 mm, and the broken lines show two series of the new resonant relation

71
calculated with α ＝ 0.78 and 0.83.
In this experiment, to save our experimental time, we have not observed the photonic crystal
radiation of the PTFE cylinders in the reflective arrangement. As reference we show Fig.5 obtained
from the same PTFE cylinders in the later experiment on the longitudinal shift (reflective

Fig.4.

The contour map of the photonic crystal radiation from the PTFE cylinders in the (kx, ω)
plane observed in the refractive arrangement. The solid and broken lines show the vn andun lines, respectively, calculated for d = 3.1 mm.

Fig.5. The contour map of the photonic crystal radiation from the PTFE cylinders of the reﬂective
arrangement measured in later experimental time on the longitudinal shift. The solid andbroken lines show the vn and un lines, respectively, calculated for d = 3.1 mm.

72
arrangement). In the ﬁgure the contour map is obtained for the emission angle θ between 60° and 120°,so the observed range θ is a little different from Fig.4. The solid and broken lines are just the same tothose in Fig.4.
During the experiment, the beam condition of the electrons fluctuated in various time scales. In
addition the tune of the electron beam suffered a little variation from experiment to experiment. These
effects resulted in various fluctuations in the experimental results, in particular to the absoluteintensity. Hence the contour map of Fig.5 suffered inﬂuence from the ﬂuctuation of the experimental
conditions. Taking into account the inﬂuence, we considered that Fig.4 held the same features as thecase of Fig.2; the second and third order dispersion relation of SPR was prominent and the photonic
crystal radiation in the low frequency seemed to be suppressed.
In the case of the cylinder monolayer, as seen in Fig.4, the new resonant dispersion relation was
not clear. We considered that the dispersion relation appeared vague because of the suppression of thephotonic crystal radiation in the low frequency.
To derive much information from the experiment, we prepared double layers of the PTFE spheres;
two monolayers of the triangular lattice of the spheres were stacked up just sphere on sphere in therefractive arrangement, as shown in Fig.6. The impact parameter was kept to 10 mm. The obtained(kx, ω) map is shown in Fig.7, where the solid lines show the dispersion relation of SPR calculated forthe diameter of the sphere d of 3.2 mm, and the broken lines show the un lines with α ＝ 0.78. Incomparison with the contour map of the monolayer, relative intensity of the photonic crystal radiationin the low frequency between 60 GHz and 120 GHz is not vague and both the SPR relation and the newresonant relation are clearly seen.
Theoretical simulation of the photonic crystal radiation from the monolayer of the triangular latticeof the PTFE spheres has been carried out under the condition that the multipole scattering of theincident evanescent wave due to the sphere was fully taken into account [5]. The results are

Experimental setup (LNSTU) Fig.6

M1

M1’

spectrometer�2dhe - beam
Fig.6.

Schematic layout of the experiment used in the experiment of two layers of the PTFE
spheres in refractive arrangement.

73
summarized as follows. The (kx, ω) map of the photonic crystal radiation shows two dispersion relations;
one was the relation of SPR and the other was corresponding to the new resonant relation, whose
gradient was roughly 0.8 times that of the SPR relation. Furthermore the (kx, ω) diagram of thephotonic crystal radiation in refractive arrangement showed almost the same features to those of
reﬂective arrangement. The theoretical dispersion relations are in accordance (or at least not conﬂict)with the experiment, though the intensity distribution along the dispersion relation was not comparedin detail between the simulation and the experiment.
On the other hand, the observed difference of the (kx,ω) maps between the two arrangements seems
not to be in accordance with the simulation. Though the origin of the difference is not clear at present,
we consider as follows. When a high-energy electron passes by near the PhC, Cherenkov radiation is
generated in the PhC. The above theoretical formulation is fully taking into account the generation of
Cherenkov radiation. However, in our experiment the size of the PTFE sphere was nearly the same tothe formation length of Cherenkov radiation [6]. It means that Cherenkov radiation is partly
suppressed in the low frequency region, λ＞ ( √ε － 1) d, where ε stands for the dielectric constant ofPTFE, i.e., √ε ＝ 1.44. Since Cherenkov radiation is an outgoing wave from the electron orbit, weconsider that Cherenkov radiation is mainly observed through the refractive arrangement. Hence thesuppression of photonic crystal radiation observed in the low frequency region is caused fromsuppression of Cherenkov radiation. Stacking of the monolayer of the PTFE spheres is considered toshift the effect of the formation length of Cherenkov radiation to the low frequency side. The low
frequency part of the (kx, ω) map of Fig.7 seems to support this explanation.

Fig.7.

The contour map of the photonic crystal radiation in the (kx, ω) plane observed with the
setup shown in Fig.6. The solid and broken lines show the vn and un lines, respectively,
calculated for d = 3.2 mm.

74§3. Superposition of Radiation from Reflective and Refractive Arrangements
To examine properties of the photonic crystal radiation, we changed the experimental setup to theone as shown in Fig.8. The two monolayers of the PTFE cylinders were separated by the distance 2h sothat the electron beam passed through the center line of the two layers along the x axis. Separation
between the two layers was controlled with a stepping motor; both the upper and lower layers weremoved along the z axis, always keeping that the impact parameter h of the upper layer was the same tothe lower one. To save the experimental time, limited number of spectra were observed and hence thecontour map of the (kx, ω) diagram was not derived.
In the experiment, we controlled the separation distance from 20.0 mm to 24.0 mm by 0.2 mm stepand observed the spectra of the photonic crystal radiation from the two layers. The spectral structure
showed complex variation with the distance and was hard to analyze. However, a few peaks of thespectrum in low frequency showed rather periodic variation. The open circles in Fig.9 show variation of
the intensity of three peaks of 75 GHz, 97.5 GHz and 157.5 GHz, observed at the emission angleθ＝ 90°.
＝ 110°, The abscissa shows half of the separation or impact
Figure 10 also shows that of 127.5GHz at θparameter h.
The photonic crystal radiation from the two layers can be taken as superposition of the photonic
crystal radiation from the upper monolayer and that of the lower layer. Let the radiation ﬁeld from theupper monolayer be expressed by（ βγλ） exp ( － i ( kx －ωt) ),E1 ＝α1 exp －

2πh

敢

1

where β ＝ v /c and γ is theExperimental
relativistic factor.
suppose that
setupWe(LNSTU)
Fig.the8 radiation field from the lower

monolayer is expressed by the same equation. Since the radiation from the lower monolayer propagatedM1
spectrometer

z
x

�

2h
e - beam

Photonic crystal
Fig.8. Schematic layout of the experiment on the superposition of photonic crystal radiation fromreﬂective arrangement and from refractive one. The electron orbit was shown by the thicksolid line.

75

Fig.9. The variation of the peak intensity as a function of beam height h observed at θ=90°. In
the ﬁgure the peak frequency was 75 GHz, 97.5 GHz and 157.5 GHz from top to bottom.
The solid curves were ﬁtted to the data by least square's method.

Fig.10.

The variation of the intensity of 127.5 GHz peak as a function of beam height h observedat θ=110°. The solid curve was ﬁtted to the data by least square's method.

76
to the observation point through the upper monolayer, we consider the radiation ﬁeld from the lower
monolayer is written by（ βγλ） exp ( － i ( kx －ωt －Δψ) ),E2 ＝α2 exp －

2πh

柑

2

where Δψ shows phase difference between two waves E2 and E1. Hence the radiation intensity from thetwo monolayers is given by, supposing that k( x2 － x1 ) ＝ 4 πh sin θ/ λ,（I ＝ E1＋ E2 2 ＝ α12 ＋α22 ＋2α1 α2 cos (

）

4πh
4πh
sin θ＋Δψ) exp ( －
).
λ
βγλ

桓

Since, in our experiment, βγ~ 300 and the variation of h was small, we can approximate Eq. [3] by
I ＝ A ＋ B cos (4πh sinθ
＋Δψ).
λ

棺

The solid curves in Figs.9 and 10 show the equation ﬁtted to the experiment by least square's method.
The solid curve is roughly in agreement with the experiment. In Fig.9, the peaks of 97.5 GHz and 157.5
GHz belong to the radiation satisfying the dispersion relation of SPR and the 75 GHz peak belongs to

the new resonant relation. The ﬁtting parameters of these peaks resulted in A ~ B, which means thatthe experiment is consistent with the above assumption.
The peak of 127.5 GHz corresponds to the point ( － 0.45, 127.5 GHz) in the (kx, ω) diagram; thepoint is placed neither on the solid lines nor on the broken ones. We can take the point corresponds toanother dispersion relation whose slope was 83% of the SPR relation. It may suggest that the photonic
crystal radiation has a few series of the new dispersion relation.

§4. Longitudinal Shift
4.1 Experiment
To examine the inﬂuence of the edge of PhC, the experimental setup was changed as schematicallyshown in Fig.11. The optical system was fabricated to collect the plane wave passing through theaperture D of 76 mm in the xz plane. The optical axis was designed to pass through the centers of theaperture and of the surface area of PhC. This optical system was common to the series of theexperiment of this report.
In this experiment, the prepared PhC was arrayed monolayer of the PTFE cylinders in reﬂective
arrangement and its position was controlled with a stepping motor to move along the x axis. The x-shiftof the PhC was measured from a ﬁxed point A and was controllable from 0 mm to 50 mm. Since thenumber of cylinders used was 27, the length of the monolayer in the x direction was 81 mm, which waslarger than the aperture D. In the case of the x-shift of 18mm, the optical axis of the measuring system
just passed through the center of the surface of the PhC. The contour map in the (kx, ω) diagram
measured with the x-shift of 18mm was shown in Fig.5.

Experimental setup (LNSTU) Fig. 1177

M1
spectrometer

z

D

x
�
A

e - beamhx-shift

Photonic crystal

Fig.11. Schematic layout on the longitudinal shift or x-shift. The electron orbit was shown by the
thick solid line. The PhC was moved horizontally along the x axis with a stepping motor.
4.2 Results and discussion
We measured the emission spectra for various positions of PhC in the x direction. The results areshown in Figs.12(a), 12(b), 13(a) and 13(b) for the emission angle θ ＝ 78°, 85°, 90°and 106°,
respectively. In these figures, spectra were shifted vertically to make the comparison clear, and thevalue of the x-shift was from 0 mm to 50 mm by 5 mm step from top to bottom. These ﬁgures in general
showed that the spectral structure was a little affected by the x-shift, even though the peak intensity
itself was varied systematically.
In Fig.12(a), the peak intensity around at 120 GHz was nearly constant and slowly decreased withthe x-shift. On the other hand, the intensity at 240 GHz increased with the x-shift. The radiation of 120
GHz belonged to the dispersion relation of the ﬁrst order SPR and that of 240 GHz to the second orderof SPR. The small peak at 165 GHz, belonging to the second order of the new resonant dispersion
relation, was nearly constant with the shift. Figure 12(b) showed that both the radiation peaks aroundat 210 GHz and 320 GHz, belonging to the 1st and 2nd order SPR, increased with the shift. The peak at
155 GHz, belonging to the 2nd order of the new resonant radiation, decreased with the shift. In
Fig.13(a) the radiation peak of 75 GHz and 140 GHz, belonging to the 1st and 2nd order of the newresonant radiation, seemed to show periodic variation with the shift. The peak of 195 GHz, belonging to
the 2nd order of SPR, gradually increased with the shift. Finally in Fig.13(b) the peak of 130 GHz
decreased with the shift and that of 225 GHz belonging to the 2nd order of SPR increased with theshift. The radiation peak of 130 GHz belongs to neither SPR nor the new resonant radiation. The peakseemed to belong other dispersion relation whose slope was 83 % of the SPR relation in the (kx , ω)diagram.
The case of the x-shift of 50 mm means that the PhC was placed at the most downstream position,and hence the upstream edge of the monolayer was near to the center of the field of view of themeasuring system. On the other hand, in the case of x-shift of 0 mm, our system observed the radiation

78

Fig.12.

Variation of the spectra observed at θ=78°(a) and 85°(b). From top to bottom, the ﬁgures
show the spectra of x-shift from 0 mm to 50 mm by 5 mm step.

emitted at the downstream edge of the monolayer. If radiation emitted from each of the cylinders was
summed up coherently, the intensity should increase with the number of the cylinders. It means thatsuch the radiation peak decreases with the shift. We therefore simply expected that the radiation peakbelonging to the dispersion of SPR decreased with the shift. On the contrary, the experiment showedthat the peaks of the SPR relation mildly increased with the shift. The reason of this contradiction is
not clear at present.
On the other hand, many of peaks belonging to the new resonant dispersion relation decreased
with the shift. It suggests whether the new resonant radiation is essential part of the photonic crystal
radiation or the radiation is emitted from the downstream edge of the monolayer. The experimentshowed implicitly that the upstream edge of the monolayer was irrelevant to the new resonantradiation.

Acknowledgement
We appreciate Professors J. Kawamura and T. Arima of IMRAM, Tohoku University, for theirencouragement and support, and professor emeritus K. Mizuno of Tohoku University for his kind

79

Fig.13.

Variation of the spectra observed at θ=90°(a) and 106°(b). From top to bottom, the ﬁgures
show the spectra of x-shift from 0 mm to 50 mm by 5 mm step.

support to utilize the low temperature InSb detector. We also thank Messrs. T. Tsutaya, Y. Chiba of
IMRAM, the member of the optical group of Photodynamics Center, RIKEN, and the staff of LNS,
Tohoku University, for their help in the experiment.

References[1]

K. Yamamoto, R. Sakakibara, S. Yano, Y. Segawa, Y. Shibata, K. Ishi, T. Ohsaka, T. Hara, Y.
Kondo, H. Miyazaki, F. Hinode, T. Matsuyama, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 69
(2004) 045601.

[2]

N. Horiuchi, T. Ochiai, J. Inoue, Y. Segawa, Y. Shibata, K. Ishi, Y. Kondo, M. Kanbe, H. Miyazaki, F.
Hinode, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 74 (2006) 056601.

[3]

S.J. Smith and E.M. Purcell: Phys. Rev. 92 (1953) 1069.

[4]

Y. Shibata, K. Ishi, T. Tsutaya, N. Horiuchi, Y. Segawa, Y. Kondo, H. Miyazaki, F. Hinode, T.
Ochiai, and K. Ohtaka: Research Report of LNS, Tohoku Univ., 39 (2006) 55.

80
[5]

H. Miyazaki: private communications (2006).

[6]

T. Takahashi, Y.Shibata, K.Ishi, M.Ikezawa, M.Oyamada, and Y. kondo: Phys. Rev. E 62 (2006)
8606.

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

81(LNS Experiment : #2537, #2553)

Properties of the Coherent Radiation Emitted from
Photonic Crystal in the Millimeter Wave Region. Ⅲ
Y. Shibata1, K. Ishi1, T. Tsutaya1, N. Horiuchi2, Y. Segawa2, Y. Kondo3, H. Miyazaki3,
and F. Hinode4
1

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira,
2

Sendai 980-8577
Photodynamics Research Center, The Institute of Physical and Chemical Research

3(RIKEN), Sendai 980-0845
Graduate School of Engineering, Tohoku University, Aramaki, Sendai 980-8579

4

Laboratory of Nuclear Science, Tohoku University, Mikamine, Sendai 982-0826

Coherent radiation emitted from a Photonic crystal of a cylindrical tube of Teflon with periodic
grooves is observed in the millimeter wave region. The observed spectra show a sharp peak at frequencyof 4.625 cm−1. The inter-bunch coherence of the radiation is conﬁrmed with an interferometer.

§1. Introduction
When a short-bunched beam of electrons of a linear accelerator passes by near the surface of a photonic
crystal (PhC), coherent photonic crystal radiation is emitted in the millimeter wavelength region [1-4].
In this report, to examine possibility of application to beam diagnostics, we have tentatively
observed photonic crystal radiation generated from high-energy electrons passing through the center ofa tube of Teﬂon, whose outer surface has periodic grooves.

§2. Experiment
The experimental setup is schematically shown in Fig.1. A short-bunched beam of electrons fromthe linear accelerator at Laboratory of Nuclear Science (LNS) , Tohoku University moved with a constantvelocity v along the center line of a cylindrical tube of a PhC. Let suppose that the center line is x axis
and horizontal plane is parallel to the xy plane. The photonic radiation from the PhC was guided by amirror system to a Martin-Puplett type Fourier transform spectrometer and was detected with a lowtemperature hot-electron bolometer. The emission angle θwas measured from the x direction.
The beam condition was as followings. The energy of the electron was 150 MeV and its spread wasless than 2.5%, the macro and micro pulse widths were roughly 1.5 μs and 0.67 ps, respectively. The
repetition of the macro pulse was 50/3 Hz and the average beam current was 0.9 μA. The cross sectionof the beam was nearly circular and about 10 mm in diameter.
The PhC was fabricated from a cylindrical tube of polytetraﬂuoroethylene（PTFE : Teﬂon）having
the size of 100 × φ60 × φ30 mm in total length × outer diameter × inner diameter. The outer surface ofthe tube had periodic grooves with cylindrical symmetry. The cross section of the groove is shown in the

82

Fig.1. Schematic layout of the experiment. The electron orbit is shown by the thick solid line. The
emission angle θ was measured from the x direction. The inset shows the shape of groove.
inset of Fig.1; the top and bottom of the grooves were semi-circle with the size of 3 mm in diameter, andthe period of the grooves was 6 mm（g = 3 mm）in the x direction.

§3. Results and Discussion
The spectra of photonic crystal radiation were observed for the emission angles θ of 110°, 100°, 90°,80° and 70°, and were shown in Fig.2. Each of the observed spectra was composed of several peaks.
Every spectrum has the main peak at frequency ν of 4.625 cm −1 or wavelength of λ = 2.16 mm and its
overtone at 9.25 cm − 1 though the intensity was weak.

Fig.2. The spectra observed at θ＝ 110°, 100°, 90°, 80° and 70°. The spectra are vertically shiftedto make comparison clear.

83
When we observed the photonic crystal radiation from the arrayed PTFE spheres or the arrayed
PTFE cylinders, the observed peaks satisﬁed the dispersion relation of Smith-Purcell radiation and/or
the new resonant dispersion relation [2-4]. The peak frequency therefore depended on the emission
angle θ. On the contrary, the peak frequency in Fig. 2 did not depend on the emission angle. The reasonof the difference is not clear at present.
The outer grooves of the Teﬂon cylinder had the period of 6 mm. Hence, the spectrum observed atθ = 90° was expected to have an intense peak at ν = 1.67 cm − 1 or at λ = 6 mm. Taking into accountthe sensitivity of our measuring system, the peak of 1.67 cm − 1 may be difﬁcult to observe. Even so, thehigher harmonics should be observed. However, the peak or one of its overtones was not observed. The
reason is not clear.
If we assume that the radiation generated in the Teflon cylinder is confined in the grooves, theradiation having a periodic condition of g √ε ＝ λ will survive, where g √ε stands for the optical length of
one groove. It is interesting that, since √ε = 1.44 for Teﬂon, the wavelength with m ＝ 2 becomes to λ =2.16 mm which corresponds to the peak wavelength. It is not clear whether the correspondence wasfortuitous or not.
The interferogram of the photonic crystal radiation was observed at θ = 90°, and is shown in Fig.3.
The interference pattern around at 0 mm in the optical path difference was repeated at around 105
mm. The result clearly showed the inter-bunch coherence of radiation generated from the S-band linac.
The experimental result showed that the observed radiation will be applicable to beam diagnostics.
However, theoretical simulation of the photonic crystal radiation is necessary to forward the application.
In the experiment, we fabricated a similar cylindrical photonic crystal of Teflon with rectangulargrooves with the same period. But the radiation was scattered over wide emission angle and weak ataround θ= 90°. It suggests that the cross section of the groove is important in the application.

Acknowledgement

Fig.3. The interferogram observed at θ＝ 90°.

84
We appreciate Professors J. Kawamura and T. Arima of IMRAM, Tohoku University, for theirencouragement and support, and professor emeritus K. Mizuno of Tohoku University for his kind
support to utilize the low temperature InSb detector. We also thank Messrs. T. Tsutaya, Y. Chiba of
IMRAM, the member of the optical group of Photodynamics Center, RIKEN, and the staff of LNS,
Tohoku University, for their help in the experiment.

References[1]

K. Yamamoto, R. Sakakibara, S. Yano, Y. Segawa, Y. Shibata, K. Ishi, T. Ohsaka, T. Hara, Y.
Kondo, H. Miyazaki, F. Hinode, T. Matsuyama, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 69 (2004)
045601.

[2]

N. Horiuchi, T. Ochiai, J. Inoue, Y. Segawa, Y. Shibata, K. Ishi, Y. Kondo, M. Kanbe, H. Miyazaki, F.
Hinode, S. Yamaguti, and K. Ohtaka: Phys. Rev. E 74 (2006) 056601.

[3]

Y. Shibata, K. Ishi, T. Tsutaya, N. Horiuchi, Y. Segawa, Y. Kondo, H. Miyazaki, F. Hinode, T.
Ochiai, and K. Ohtaka: Research Report of LNS, Tohoku Univ., 39 (2006) 55.

[4]

Y. Shibata, K. Ishi, T. Tsutaya, N. Horiuchi, Y. Segawa, Y. Kondo, H. Miyazaki, F. Hinode, T.
Ochiai, and K. Ohtaka: Research Report of LNS, Tohoku Univ., 39 (2006) 67.

核理研研究報告

第39巻

2006

85

新しい管理区域入退管理システム
柴崎義信，菅原由美，結城秀行，山崎寛仁，大槻勤
東北大学院理学研究科附属原子核理学研究施設（982-0826 仙台市太白区三神峯 1-2-1）§１．はじめに
東北大学理学研究科附属原子核理学研究施設では，放射線管理区域への入室者管理のため1998年に入退室管理システム［1］を独自開発し運用してきた。当初は比較的安定した動作を行っていたが，運用から間もなく10年となる現在，いくつかの問題が出てきている。ひとつは，管理に使用しているコンピュータのオ
ペレーティングシステム（OS）の問題である。OS は，WindowsNT4.0を使用しているが，その後バージョンが改訂され，現在は Windows2003および WindowsXP となっている。しかし，管理システムは，OS のバージョンに依存したコードを使用していることや，使っているコンピュータ（PC）の制約で簡単にバージョンアップすることができない。現在，WindowsNT4.0のサポートは打ち切られており早急な対策が必要となっていた。
次の問題は，管理システムに使用しているデータベースソフトの問題が挙げられる。データベースには，
マイクロソフトのアクセスを使用していた。このソフトは軽量であり開発も比較的簡単に行うことができる
がデータ数が多くなったときにパフォーマンスが低下し，入退室処理に時間がかかったりシステムが停止す
るなどの現象が現れてきた。
また，もうひとつ問題をあげることができる。入室登録と入室のための扉の電子錠管理は，それぞれ異なる PLC により行っている。電子錠管理では入室登録の情報が必要だが，この情報共有を PLC とネットワー
クで接続している PC を中心とした OMRON のデータリンク機能を使って行っている。これは，設定のみで情報共有を行うことができ便利であるが，複数の PLC がお互いのデータに依存する関係となるため，ある箇所の障害が別の箇所に波及しシステム全体を不安定にする要因になっている。
放射線管理区域への入退室管理は，放射線取り扱い施設として重要な業務のひとつであり，システム停止の状態に陥ることは許されないことである。そのため，2006年にシステム更新のための予算化がなされ再構築をおこなった。

§２．新しいシステムの開発方針
これらの問題点を改善し，また将来の拡張や変更にも対処できるようにするためには，汎用的な技術を取り入れ，独自開発的な部分はどうしても必要な箇所に限定することが重要である。また，それぞれの機能を密に結合させないことでひとつの変更が他をも変更しなければならない状況を作り出さないことも重要である。
最近の情報技術の進歩によって，インターネットを中心とした情報伝達システムが標準的に使われるようになってきた。この技術を今回のシステムに応用することで将来への拡張性や保守性を確保できる。この中心となる技術がデータベースを中心とした Web サービスと Web アプリケーションである。
アプリケーションを作成する上では，プログラミング開発環境とプログラム言語に何を選択するかが開発
効率に影響する。Web を中心とした開発では，Web ブラウザが解釈できる HTML や，スクリプトとしての86
java が一般的に使われている。これらの言語を用いて直接開発することもできるが，効率や今後の管理という側面からは必ずしも適当であるとはいえない。核理研では加速器の制御プログラム [2] の開発にはMicroSoft の VisualBasic を用いているが，今回のシステム開発に同じ環境を用いることで迅速な開発を行うことができる。
以上のことを考慮し今回のシステム更新では次のような基本方針を立てた。
１．SQL Server 2005の採用
２．Web サービスによる情報共有
３．Web ブラウザによる各種情報の表示と取り出し
４．PLC のローカル化§２．システムの構成
これまでのシステムは，ひとつの PC に多くの機能を持たせていた。それが OS のバージョンアップを阻害していたひとつの原因ともなっていた。そこで，PC 毎に機能を分散させ，使い方を限定することでこの問題へ対処した。また，PC の故障時に問題が波及することを最小限にすることもできる。このためには，
まずシステムが必要としている機能を整理する必要がある。機能を整理すると以下のとおりとなる。
１．データベース
２．入退室登録
３．入室ゲート管理
４．入室者一覧表示
５．入室者都度印刷
６．管理ユーザー登録
７．ID カード作成
８．月報取り出し
データベースは，ユーザー情報や入室退室の状況，ゲート通過記録などの情報を保存する機能で，これまでアクセスによって行われていたものである。保存するデータの項目は以前とそれほど変わらないが，検索速度を上げるためテーブル構造とトランザクションの方法を変えている。また，データベース管理ソフトとしてマイクロソフトが最近提供を開始した SQL2005を採用した。
入退室登録は，作業や他の目的で管理区域に入室しようとする人がまず行う作業で，入室先などの情報をデータベースへ登録する。ここでは，登録者の ID カードを読み込むための ID センサと，登録情報を入力するためのタッチパネルを必要とする。
入室ゲート管理は，入室登録を済ませたユーザーが入室扉を通過することを管理する機能で，通過者の情報をデータベースに記録する。ここには，電子錠制御と ID センサ読み取りを行うための PLC がある。
入室者一覧表示は，入室登録を済ませたユーザーとその人がゲートを通過したかどうかを表示する。
入室者都度印刷は，入退室登録を行ったユーザーをその都度印刷し記録する。
管理ユーザー登録は，新入生や新採用，転勤などで新たに核理研の管理区域に入室する必要が出てきた人をデータベースに登録する機能である。
ID カード作成は，ユーザー登録により必要となる ID カードの作成をおこなう。
月報取り出しは，月毎の管理区域入室と退室のログを取り出す機能で，個人毎及び時系列で印刷し保存する。

87
これらの機能で，直接 PLC などのハードウエアを制御するものについては，プログラミングの必要があることから Web サービスを利用してデータベースと通信を行う。それ以外については，Web アプリケーショ
ンとし，Web ブラウザを使って表示や入力を行うことができるようにした。Web ブラウザを使うことで PCの機種を限定する必要がなくなり，特定の PC を管理するわずらわしさをなくすることができる。
今回の更新では，これまでの ID カードをそのまま使うこととし，ゲートを制御している PLC への変更を行っていない。PLC は，専用の PC を介して制御し，ネットワークから切り離した。それぞれの PC は，専用のネットワークから所内のローカルネットワークへ接続を切り替え，これまで専用のネットワークと，所
内ネットワークへ混在した接続を整理した。新しいシステムの構成とネットワーク接続を第１図に示す。

第１図

システム構成図。

（1） データベース
データベースは，このシステムの中心となるためテーブル構造が使い勝手やパフォーマンスを決める要因となる。また，これまで使っていたデータベースのテーブル構造も必要に応じて継承する必要がある。ただし最初に作られたテーブルは不必要と思われるフィールドもあるため，
再度必要項目について分析を行った。
テーブルは大きく分けて次の３種類に分類した。
・共通情報

・一時情報

・記録情報

共通情報は，ユーザー情報や実験室名などの頻繁に更新されることのない情報を格納するテーブルで管理者によって登録や削除などの管理を行う。
一時情報は，
ユーザーが入室している時の状態を管理するテーブルで，このシステムの動作の要となるテー

88

第２図

データベースモデル図。

ブル群である。このテーブルには，入室登録時にゲート通過や表示に必要な情報が書き込まれ，退室手続時に削除されるため頻繁にトランザクションが発生する。そのためこのテーブルの設計が全体のパフォーマンスに影響する。
記録情報は，最終的に記録として残すべきデータを格納するテーブルで，ユーザーごとに集計し入室時間や被曝線量などを管理する。
また，これ以外にユーザーインターフェースとして表示する内容を動的に変更するための情報を管理する
テーブルを作成した。たとえば，日本語圏以外のユーザーには英語で表示するとか，入室目的や入室先の名前を変更したい場合などがこれにあたる。アプリケーションは表示するときにこのテーブルを参照し表示方
法を変えることができるためプログラムの変更が必要なくなる。
今回の構築で作成したデータベースのテーブル構造をデータベースモデル図として第２図に示す。

89

第３図

テーブルアクセスシーケンス。

これらのテーブル構造と種類は，あらかじめユーザーが入退室するためにはどのようにするか，またそのときにどのような情報が必要かを登録から退室手続までのシナリオを作成し，そこからテーブルへアクセスする手順を視覚化した。この作業を繰り返し，必要なものと不必要なものを切り分け作成するテーブルの確定とテーブルから情報を取り出すシーケンスを決定した。この作業は，このシステムを管理する管理者側からの分析も行い，より洗練させている。第３図にユーザーが入退室する手順による各テーブルへのアクセス
シーケンスを示す。
（2） Web サービスと分散オブジェクト
入退室登録端末やゲートを管理している機器などのクライアントからデータベースへのアクセスは，直接には行わず，Web サービスを使って入退室情報をカプセル化したオブジェクト（第４図参照）の交換で実現している。それによって，クライアント側ではデータベースの構造を気にする必要がなくなりオブジェク
トに処理を依頼するだけですむ。また，テーブル構造などを何らかの理由で変更する場合にもクライアントのプログラムを変える必要がなくなり管理作業を単純にすることが可能となった。
（3） インターフェースプログラムと開発環境
このシステムは，実際に入退室を行うユーザーや，ユーザー及び記録情報を管理する管理者との対話を行
うため必要な情報の表示および入力のためのインターフェースが必要である。これを入退室登録者の流れに沿ってまとめると第５図のようなアプリケーションが必要となる。
これらのプログラムを作るにあたっては，先に述べた方針に従って，可能なものは Web アプリケーショ
ンとしWebブラウザで対応できるようにした。そのため特別のハードウエアを動作させる必要のないものは，

90

第４図

Web サービスのクラス図。

Web サーバーを中心とした Web アプリケーションとして構成している。
Web アプリケーションの作成は，HTML を使ってページを作成し，動的に動作する機能はスクリプトとしてページに埋め込む。ユーザーからのアクションによってポストバックされた情報は，その種類に応じてザーバー側で処理されその結果を新しい Web ページとして構築しブラウザに表示する。この一連の流れをプログラムする方法として ASP.NET を使った。これは，コードビハインドという技術を使って，表示する部分と動作の部分を分割してプログラムする方法で，表示部分にプログラムが入り込まないのでそれぞれに専念した開発を行うことができるのが特徴である。また，動作コードについては VisualBasic で記述することができるためこれまでのプログラミング技術をそのまま使うことが可能であり開発時間の短縮を図ることができる。
このシステムでは，入退室時に登録したデータを個人ごとや日付ごとに入室時間とそのときの被曝線量の累計を月単位で記録し保管する。そのためには，記録しているデータを加工し並べ替えを行いそれらの閲覧と印刷あるいはエクセルなどの別の汎用アプリケーションへのエキスポートなどの機能を必要とする。これ
らの機能を Web アプリケーションとして作成することも可能であるが，今回採用した SQL サーバー2005には，レポーティングサービスとしてこれらを実現する方法を備えている。開発は，Web アプリケーション

91を開発する場合と同じ開発環境を使い，表示するために必要な表をフォーム上に配置し，データベースからどのようにデータを取り出すかのクエリを設定するだけで実現できる。クエリコマンドの作成もウィザードが準備されており，その指示に従って入力するだけで高度なクエリ文の作成ができる。第６図に開発中の様子と実際にＷｅｂブラウザで表示したページを示す。
今回の開発に用いた環境およびハードウエアの仕様を次に示す。
サーバー : Dell PowerEdge SC1425
CPU: Xeon64bit 3GHz
メモリ : ２GB
OS: WindowsServer2003x64
データベース : SQL2005
開発環境 : VisualStudio2005
開発言語 : VisualBasic.NET

第５図

入退室登録の流れとアプリケーション。

92

第６図

VisualStudio によるレポート開発（上）と開発したレポートの表示（下）。

93§３．運用状況
このシステムは，2006年3月より開発に着手し，8月上旬に旧環境との入れ替えを行い運用を開始した。
運用前の試験については，かなり限定された環境のみでしか行うことができなかったが，運用を開始した8月からこれまでのシステム動作の中で若干のプログラムのバグによる問題以外は大きく仕様を見直すような
不具合はなく順調に稼働している。一部，ID カード読み取り部で読み取りができない不具合が発生するという以前からの問題は残っている。これについては，PLC の読み取りプログラムを変更する必要がある。
システムのパフォーマンスは，PC の性能の問題もあるが，旧システムより体感的に速く感じられ入退室時のストレス軽減につながっている。また，入室状況は Web アプリケーションとして提供しており，どこからでも確認することが可能となっている。

§４．ま と め
今回の目的である新しい放射線管理区域への管理区域入退管理システム構築は完了した。これにより，懸案となっていたコンピュータの更新と最新の OS への対応が可能となった。また，パフォーマンスも向上し登録作業も迅速に行えるようになった。ただ，一部従来の機器がそのまま残っており更新等の作業は必要である。
シ ス テ ム 構 築 に あ た っ て は，ま ず 入 退 室 管 理 シ ス テ ム と し て の 機 能 の 分 析 を 行 い 次 に 開 発 を
VisualStudio2005および ASP.NET を使って機能の部品化を図った。それにより短い開発期間によって完成することができた。

参

考

文

献

[1]

宮本篤他 :“管理区域入退管理システムの開発”，RADIOISOTOPES, Vol.52, No.12（2003）.

[2]

Y. Shibasaki et al.: New Control System for the LNS Linac, PCaPAC2002 MO-P20（2002）.

Ⅳ．List of Publication

Research Report of Laboratory of Nuclear Science, Tohoku University Vol. 39 (2006)

95

List of Publication（論文リスト）（2005.1～2005.12）
Papers Published in Refereed Journals
K0 Photoproduction on 12C in the Threshold Region.
T. Watanabe, S. Endo, Y. Fujii, O. Hashimoto, K. Hirose, T. Ishikawa, K. Ito, H. Kanda, M.
Katoh, T. Kinoshita, O. Konno, K. Maeda, A. Matsumura, Y. Miura, F. Miyahara, H.
Miyase, K. Mizunuma, T. Nakabayashi, S.N. Nakamura, H. Nomura, Y. Okayasu, T.
Osaka, A. Otani, M. Oyamada, A. Sasaki, T. Sato, H. Shimizu, T. Takahashi, T. Tamae, H.
Tamura, T. Terasawa, H. Tsubota, K. Tsukada, M. Ukai, M. Utoyama, M. Wakamatsu, H.
Yamauchi, Y. Yamaguchi, Y. Yamamoto, and H. Yamazaki
Nuclear Physics A754 (2005) 327-331.
Direct Evidence of Core Excitation in the Giant Resonance through the (e,e'n) Reaction.
T. Saito, K. Yoshida, M. Oikawa, Y. Suga, T. Nakagawa, T. Tohei, K. Abe, and H. Ueno
Phys. Rev. C71 (2005) 064313 (1-5).
The 1.2 GeV Photon Tagging System at LNS-Tohoku.
H. Yamazaki, T. Kinoshita, K. Hirota, T. Katsuyama, T. Itoh, A. Katoh, T. Nakabayashi,
O. Konno, T. Takahashi, K. Maeda, J. Kasagi
Nucl. Instr. Meth. A536 (2005) 70-78.
φ Photo-production from Li, C, Al and Cu nuclei at Eγ =1.5-2.4 GeV.
T. Ishikawa, D.S. Ahn, J.K. Ahn, H. Akimune, W.C. Chang, S. Date, H. Fujimura, M.
Fujiwara, K. Hicks, T. Hotta, K. Imai, H. Kawai, K. Kino, H. Kohri, T. Matsumura, T.
Mibe, K. Miwa, M. Miyabe, M. Morita, T. Murakami, N. Muramatsu, H. Nakamura, M.
Nakamura, T. Nakano, M. Niiyama, M. Nomachi, Y. Ohashi, T. Ooba, D.S. Oshuev, C.
Rangacharyulu, A. Sakaguchi, Y. Shiino, Y. Sakemi, H. Shimizu, Y. Sugaya, M. Sumihama,Y. Toi, H. Toyokawa, C.W. Wang, T. Yorita, M. Yosoi, and R.G.T. Zegers
Phys. Lett. B608 (2005) 215-222.
Near-Threshold Diffractive φ Meson Photoproduction from the Proton.
T. Mibe, W.C. Chang, T. Nakano, D.S. Ahn, J.K. Ahn, H. Akimune, Y. Asano, S. Daté, H.
Ejiri, H. Fujimura, M. Fujiwara, K. Hicks, T. Hotta, K. Imai, T. Ishikawa, T. Iwata, H.
Kawai, Z.Y. Kim, K. Kino, H. Kohri, N. Kumagai, S. Makino, T. Matsuda, T. Matsumura, N.
Matsuoka, K. Miwa, M. Miyabe, Y. Miyachi, M. Morita, N. Muramatsu, M. Niiyama, M.
Nomachi, Y. Ohashi, T. Ooba, H. Ohkuma, D.S. Oshuev, C. Rangacharyulu, A. Sakaguchi, T.
Sasaki, P.M. Shagin, Y. Shiino, H. Shimizu, Y. Sugaya, M. Sumihama, A.I. Titov, Y. Toi, H.
Toyokawa, A. Wakai, C.W. Wang, S.C. Wang, K. Yonehara, T. Yorita, M. Yoshimura, M.
Yosoi, and R.G.T. Zegers
Phys. Rev. Lett. 95 (2005) 182001 (1-5).
Investigation of the Conjectured Nucleon Deformation at Low Momentum Transfer.
N.F. Sparveris, R. Alarcon, A.M. Berstein, W. Bertozzi, T. Botto, P. Bourgeois, J. Calarco, F.

96Casagrande, M.O. Distler, K. Dow, M. Farkondeh, S. Georgakopoulos, S. Gilad, R. Hicks, M.
Holtrop, A. Hotta, X. Jiang, A. Karabarounis, J. Kirkpatrick, S. Kowalski, R. Milner, R.
Miskimen, I. Nakagawa, C.N. Papanicolas, A.J. Sarty, Y. Sato, S. Širca, J. Shaw, E. Six, S.
Stave, E. Stilaris, T. Tamae, G. Tsetalovich, C. Tschalaer, W. Turchinetz, Z.-L. Zhou, and T.
Zwart
Phys. Rev. Lett. 94 (2005) 022003 (1-4).
Measurement of the 3He(e,e'p)pn Reaction at High Missing Energies and Momenta.
Benmokhtar, M.M. Rvachev, E. Penel-Nottaris, K.A. Aniol, W. Bertozzi, W.U. Boeglin, F.
Butaru, J.R. Calarco, Z. Chai, C.C. Chang, J.-P. Chen, E. Chudakov, E. Cisbani, A.
Cochran, J. cornejo, S. Dieterich, P. Djawotho, W. Duran, M.B. Epstein, J.M. Finn, K.G.
Fissum, A. Frahi-Amoroun, S. Frullani, C. Furget, F. Garibaldi, O. Gayou, S. Girad, R.
Gilman, C. Glashausser, J.-O. Hansen, D.W. Higinbotham, A. Hotta, B. Hu, M. Iodice, R.
Iomni, C.W. de Jager, X. Jiang, M.K. Jones, J.J. Kelly, S. Kox, M. Kuss, J.M. Laget, R. De
Leo, J.J. LeRose, E. Liatard, R. Lindgren, N. Liyanage, R.W. Lourie, S. Malov, D.J.
Margaziotis, P. Markowitz, F. Merchez, R. Michaels, J. Mitchell, J. Mougey, C.F. Perdrisat,
V.A. Punjabi, G. Quéméner, R.D. Ransome, J.-S. Réal, R. Roché, F. Sabatié, A. Saha, D.
Simon, S. Strauch, R. Suleiman, T. Tamae, J.A. Templon, R. Tieulent, H. Ueno, P.E. Ulmer,
G.M. Urciuoli, E. Voutiner, K. Wijesooriya, and B. Wojtsekhowski
Phys. Rev. Lett. 94 (2005) 082305 (1-5).
Quasielastic 3He(e,e'p)2H Reaction at Q2 = 1.5 GeV2 for Recoil Momenta up to 1 GeV/c.
M.M. Rvachev, F. Benmokhtar, E. Penel-Nottaris, K.A. Aniol, W. Bertozzi, W.U. Boeglin, F.
Butaru, J.R. Calarco, Z. Chai. C.C. Chang, J.-P. Chen, F. Chudakov, E. Cisbani, A. Cochran,J. Cornejo, S. Dieterich, P. Djawotho, W. Duran, M.B. Epstein, J.M. Finn, K.G. Fissum, A.
Frahi-Amroun, S. Furullani, C. Furget, F. Garibaldi, O. Gayou, S. Gilad, R. Gilman, C.
Glashausser, J.-O. Hansen, D.W. Higinbotham, A. Hotta, B. Hu, M. Iodice, R. Iomni, C.W.
de Jager, X. Jiang, M.K. Jones, J.J. Kelly, S. Kox, M. Kuss, J.M. Laget, R. De Leo, J.J.
LeRose, E. Liatard, R. Lindgren, N. Liyanage, R.W. Lourie, S. Malov, D.J. Marganziotis, P.
Markowitz, F. Merchez, R. Micaels, J. Mithcell, J. Mougey, C.F. Perdrisat, V.A. Punjabi, G.
Quéméner, R.D. Ransome, J.-S. Réal, R. Roché, F. Sabatié, A. Saha, D. Simon, S. Strauch, R.
Suleiman, T. Tamae, J.A. Templon, R. Tieulent, H. Ueno, P.E. Ulmer, G.M. Yriuoli, E.
Voutier, K. Wijesooriya, and B. Wojtsekhowski
Phys. Rev. Lett. 94 (2005) 192302 (1-5).
First Beam Test on a BSO Electromagnetic Calorimeter.
H. Shimizu, F. Miyahara, H. Hariu, T. Hayakawa, T. Ishikawa, M. Itaya, T. Iwata, T.
Kinoshita, M. Moriya, T. Nakabayashi, T. Sasaki, Y. Tajima, S. Takita, M. Yamamoto, H.
Yamazaki, H.Y. Yoshida, and Y. YoshidaNucl. Instr. and Meth. Phys. Res. A550 (2005) 258-266.
不安定核電子散乱実験のための自己閉じ込め型不安定核標的 (SCRIT).
若杉昌徳，伊藤祥子，江本隆，大西哲哉，栗田和好，小関忠，白井敏之，須田利美，竹田浩之，

97
玉江忠明，頓宮拓，中村仁音，野田章，古川幸弘，増田鉄也，森川斉，矢野安重，王頌
加速器，2 (2005) 337-347.
Production of Th-229m in Nuclear Reaction and its Identiﬁcation by Alpha-spectrometry.
H. Kikunaga, Y. Kasamatsu, K. Takamiya, T. Mitsugashira, M. Hara, T. Ohtsuki, H. Yuki, A.
Shinohara, S. Shibata, N. Kinoshita, A. Yokoyama, and T. Nakanishi
Radiochimica Acta 93 (2005) 507-510.
Photon Activation Analysis of Carbon in Glasses for Fiber Ampliﬁers by using the Flow Method
for the Rapid Separation of 11C.
K. Shikano, A. Mori, M. Shimizu, T. Ohtsuki, H. Yuki, K. Masumoto
J. Radioanal. Nucl. Chem. 266 (2005) 211-216.
Formation of 210Po @C60.
T. Ohtsuki and K. Ohno
Phys. Rev. B72 (2005) 153411 (1-3).
Investigation of the Decay Property of 229mTh by Photon Detection.
Y. Kasamatsu, H. Kikunaga, K. Takamiya, T. Mitsugashira, T. Nakanishi, Y. Ohkubo,
T. Ohtsuki, W. Sato, and A. Shinohara
Radiochim. Acta, 93 (2005) 511-514.
Papers Published in International Conference Proceedings
φ Photo-Production from Nuclei at SPring-8/LEPS.
T. Ishikawa
Proceedings of the International Workshop on Quark Nuclear Physics 2005 (2005).
Detection of Nuclear De-excitation Gamma-rays in Water Cherenkov Detector.
K. Kobayashi, Y. Itow, M. Shiozawa, M. Yosoi, H. Toyokawa, H. Akimune, H. Ejiri, H.
Fujimura, M. Fujiwara, K. Hara, K.Y. Hara, T. Ishikawa, M. Itoh, T. Kawabata, M.
Nakamura, H. Sakaguchi, Y. Sakemi, H. Takeda, M. Uchida, T. Yamada, Y. Yasuda, H.P.
Yoshida, and R.G.T. Zegers
Nuclear Physics B - Proceedings Supplements, 139 (2005) 72-76.
Lattice Modiﬁcation of a 1.2 GeV STB Ring for Generation of High Energy Gamma-rays using Internal
Target Wire.
F. Hinode, H. Hama, M. Kawai, A. Kurihara, A. Miyamoto#, M. Mutoh, M. Nanao, Y.
Shibasaki, K. Shinto, S. Takahashi, and T. Tanaka
Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee, (2005)
2458-2460.
Study of Slow Beam Extraction through the Third Order Resonance with Transverse Phase Space
Manipulation by a Mono-frequency RFOK.
A. Miyamoto, F. Hinode, M. Kawai, K. Shinto, T. Tanaka, and H. Hama
Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee, (2005)
1892-1894.

98
Simulation Study of a Thermionic RF Gun for High Brightness and Short Pulse Beam.
T. Tanaka, F. Hinode, M. Kawai, A. Miyamoto, K. Shinto, and H. Hama
Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee, (2005)
3499-3501.
An Independently Tunable Cells Thermionic RF Gun (ITC-RF GUN) for Sub-picosecond Short Pulse.
T. Tanaka, F. Hinode, M Kawai, and H. Hama
Proceedings of the 27th International Free Electron Laser Conference, FEL2005, Stanford,
CA, USA (2005) 142-145.
ReviewIs the Property of Mesons Modiﬁed in the Nuclear Medium? " φ Meson Photoproduction from Nuclei".
T. Ishikawa and M. Fujiwara
ROKKO Publishing & Sale Co. SPring-8 Research Frontiers 2004 (2005) 149-150.
フラーレンに内包された軌道電子捕獲崩壊核種 7Be の半減期 .
大槻勤
アイソトープニュース（日本アイソトープ協会）5 (2005)14-17.
放射性同位元素の半減期は変化するか？：C60 内に 7Be が内包された場合 .
大槻勤
日本物理学会誌（最近の研究から）7 (2005) 551-554.
フラーレン中の放射性同位元素 Be-7 の半減期 .
大槻勤
放射線化学 80 (2005) 41-46.
C60 中の EC 崩壊核種（ベリリウム -7）の半減期絶対測定 .
大槻勤
JAERI-Conf 2005-011 (2005) 126-130.

Ⅴ．Approved Experiments

99

平成 17 年度前期採択課題一覧表
課題番号

課

題

名

申込責任者

採
択
シフト数

原子核関連分野
2534

D ( γ , η) 反応における E γ～1.02 GeV の新共鳴状態の確定

山崎

寛仁

39

2535

A ( γ , η) 反応による核子共鳴 D13 (1520) の研究

笠木治郎太

20

2536

４π立体角

多重ガンマ線検出器群 FOREST（仮称）の建設

石川

貴嗣

施設実施

柴田

行男

8

放射光関連分野
2537

フォトニック結晶からのコヒーレントな放射の研究款
－フォトニック結晶配置方位依存性の測定－

放射化学・物性関連分野
2538

長寿命放射性核種の環境中移行における基礎化学反応研究

関根

勉

2

2539

光量子放射化分析法による光通信用材料中の不純物評価

鹿野

弘二

1

2540

標識化による金属内包フラーレン及びヘテロフラーレンの研究及
びその応用

大槻

勤

2

2541

Ac-229から Th-229m, g への壊変過程に関する研究

中西

孝

1

2542

Th-229m の製造とその崩壊特性

三頭

聰明

1

2543

宇宙化学的試料および環境試料の光量子放射化分析

海老原

充

2

2544

電子ビームによるフリーラジカル生成の研究

結城

秀行

1

2545

金属及び半導体材料中の軽元素の定量のための分離・捕集法の開
発

桝本

和義

2

2546

水素誘起空孔による拡散の促進

佐藤伊佐務

1

2547

DNA２本鎖切断の遺伝的影響；１倍体酵母と二倍体酵母の比較
研究

山崎

4

仁丈

100

平成 17 年度後期採択課題一覧表
申込責任者

採
択
シフト数

2548

A ( γ , η) 反応における閾値エネルギー近傍での S11 共鳴の励起関数測定－核媒質による共鳴エネルギー減少の可能性－

笠木治郎太

24

2549

NKS2 実験のための BM4 ガンマビームライン整備

前田

和茂

12

2550

指向性をもった電子検出器の性能評価

友野

大

12

2551

重水素原子核標的での2π光生成反応の研究

前田

和茂

20

2552

Photoproduction of Neutral Kaons on Deuterium Target near
Threshold Region

橋本

治

52

柴田

行男

4

課題番号

課

題

名

原子核関連分野

放射光関連分野
2553

フォトニック結晶からのコヒーレントな放射の研究歓－フォトニック結晶配置依存性の測定－

放射化学・物性関連分野
2554

標識化による金属内包フラーレン及びヘテロフラーレンの製造及びその応用研究

大槻

勤

2

2555

長寿命放射性核種の環境中移行における基礎化学反応研究

関根

勉

2

2556

水素誘起空孔による拡散の促進

山崎

仁丈

1

2557

制動放射線誘導放射性核種の生成量に関する実測値と計算値の比
較

中西

孝

3

2558

光量子放射化分析法による光通信用材料中の不純物評価

鹿野

弘二

1

2559

金属及び半導体材料中の軽元素の定量のための分離・捕集法の開
発

桝本

和義

2

2560

宇宙化学的試料および環境試料の光量子放射化分析

大浦

泰嗣

2

2561

固体抽出剤を用いた希土類元素とアクチノイド元素の分離に関す
る研究

鈴木

達也

3

2562

電子ビームによるフリーラジカル生成の研究

結城秀行

1