Nhng tin b trong Quang hc, Quang ph và ng dng VI ISSN 1859 - 4271

Những tiến bộ <strong>trong</strong> <strong>Quang</strong> học, <strong>Quang</strong> <strong>ph</strong>ổ và Ứng dụng VI ISSN 1859 - 4271IMPURITY-DOPED ZNO SCINTILLATOR FOR PRECISESYNCHRONIZATION OF FEMTOSECOND PULSES FROM XFEL ANDCONVENTIONAL ULTRAFAST LASERNobuhiko Sarukura 1,4 , Pham Minh 1 ,Toshihiko Shimizu 1,4 , Kohei Yamanoi 1,4 , Kohei Sakai 1 ,Marilou Cadatal-Raduban 1 , Elmer Estacio 1 , Tomoharu Nakazato 1,4 , Masataka Kano 2 , AkiraWakamiya 2 , Dirk Ehrentraut 3 , Tsuguo Fukuda 3 , Mitsuru Nagasono 4 , Tadashi Togashi 4,5 ,Shinichi Matsubara 4,5 , Kensuke Tono 4 , Atsushi Higashiya 4 , Makina Yabashi 4 , HiroakiKimura 4,5 , Haruhiko Ohashi 4,5 , and Tetsuya Ishikawa 41 Institute of Laser Engineering Osaka University 2-6 Yamadaoka, Suita, Osaka 565-0871 Japan2 Daishinku Corporation, 1389 Shinzaike, Hiraoka-cho, Kakogawa, Hyogo 675-0194, Japan3 WPI Advanced Institute for Materials Research Tohoku University2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan4 RIKEN XFEL Project Head Office, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan5 Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-choSayo-gun, Hyogo 679-5198, Japan.E-mail: sarukura-n@ile.osaka-u.ac.jpAbstract. Response time of an Indium ion-doped zinc oxide scintillator is measured to be ~3 ps, animproved of almost 50 times compared to the previously reported Iron ion-doped counterpart.Intentional impurity-ion doping introduces additional fluorescence quenching channels that facilitateshortening of the response time. This improved response time allows timing control between x-rayfree electron laser pulses and a femtosecond laser to within a few picosecond accuracy.Keywords: Scintillator, X-ray free electron laser, Zinc oxide.I. INTRODUCTIONAt present, facilities aimed at designing and construc<s<strong>trong</strong>>tin</s<strong>trong</strong>>g pulsed X-ray sources have led to theproduction of femtosecond or even attosecond pulses to be employed in state-of-the-art singlemoleculeprotein X-ray diffraction measurements[1]. In this regard, accurate timingsynchronization between short-wavelength femtosecond pulses from X-ray free-electron lasers(XFEL) and short optical-pulses from other light sources is required for pump and probeexperiments in XFEL facilities. As such, the availability of fast scintillators becomes even moreimportant. The widely-used Ce:YAG crystal, with a 50-ns response time, is insufficient formeaningful temporal studies of X-ray pulses. Previously, a hydrothermal method-grown, largesizedZnO crystal was shown to be a fast extreme ultraviolet scintillator. Its 1-ns response timemakes it very promising for 13-nm next generation lithogra<strong>ph</strong>y [2-4]. Previously, we havereported a Fe-doped, hydrothermal method grown, ZnO crystal, which exhibited an over oneorder-of-magnitude response time increase compared with previous results [5]. In this paper, wereport further shortening of the ZnO scintillator response time to 3.1 ps, which is animprovement of nearly 50 times compared to the previously reported Fe-doped ZnO byintentionally doping with indium (In) and significantly reducing lithium (Li) in the star<s<strong>trong</strong>>tin</s<strong>trong</strong>>gsolution. Using this response time-improved, In-doped ZnO, we are able to measure the jitterbetween 200-fs pulses from the XFEL prototype, Spring-8 compact self amplification of55