Crystal Scintillators for High Precision EM Calorimeters

collaboration with M. Ishii (Shonan Inst. Tech.), M. Kobayashi (KEK), Y. Usuki (Furukawa), and H. Ishibashi (Hitachi Chemical)


We are aiming at development of scintillators applicable to high precision electromagnetic calorimeters at future high luminosity hadron collider experiments. Such scintillators have to be radiation hard (to 10 Mrad at least), fast (~20 ns), bright, and stable. Since 1995 Tsukuba group has been a collaborator with the group of Ishii-Kobayashi-Ishibashi-Usuki who has been leading the oxide crystal scintillator development for more than 10 years. One of the candidate scintillators is PWO lead tungstate (see this table). This material is being actively developed for the CMS experiment at CERN LHC. In the following publication we have shown that doping of La improves light transmittance and radiation hardness to the level that can be usable at CMS. Another material we are investigating is gadolinium silicate GSO. This has been developed at Hitachi Chemical. The main features (see this table) are radiation hardenss to ~1 Grad and brightness (x~100 of PWO).

Lead Tungstate, PWO

  • "Scintillation characteristcis of PWO4 single crystals doped with Th, Zr, Ce, Sb and Mn ions",
    M. Kobayashi, Y. Usuki, M. Ishii, T. N. Sentuttuvan, K. Tanji, M. Chiba, K. Hara, M. Tanaka, M. Nikl, P. Bohacek, S. Baccaro, A. Cecilia, M. Diemoz, A. Vedda, M. Martini
    NIM A465, 2001, 428-439.

  • "Crystal growth of PbWO4 by vertical Bridgman method: Effect of crucible thickness and melt composition",
    K. Tanji, M. Ishii, Y. Usuki, M. Kobayashi, K. Hara, H. Takano, N. Senguttuvan,
    J of Crystal Growth 204 (1999) 505-511.

  • "Significant Improvement of PbWO4 scintillating crystals by doping with trivalent ions",
    M. Kobayashi et al.,
    NIM A434 (1999) 437-445.

  • "La-doped PbWO4 Scintillator Crystals Grown in Large Ingots",
    K. Hara, M. Ishii, M. Kobayashi, M. Nikl, H. Takano, M. Tanaka, K. Tanji, Y. Usuki
    NIM A414, 1998, 325.

  • "Improvement in Radiation Hardness of PbWO4 Scintillating Crystals by La-Doping",
    M. Kobayashi, Y. Usuki, M. Ishii, T. Yazawa, K. Hara, M. Tanaka, M. Nikl, S. Baccaro, A. Cecilia, M. Diemoz, I. Dafinei
    NIM A404, 1998, 149-156.

  • "Improvement in Transmittance and Decay Time of PbWO4 Scintillating Crystals by La-Doping",
    M. Kobayashi, Y. Usuki, M. Ishii, T. Yazawa, K. Hara, M. Tanaka, M. Nikl, S. Baccaro, A. Cecilia, M. Diemoz, I. Dafinei
    NIM A399, 1997,261-268.

  • "Lead Deficiency in Single Crystals of PbWO4 Grown in Air",
    Y. Usuki (Furukawa, Yoshima), M. Ishii (Shonan Inst. Tech.), M. Kobayashi (KEK, Tsukuba), K. Hara, M. Tanaka (U Tsukuba), M. Nikl, K. Nitsch (Prague, Inst. Phys.). KEK-PREPRINT-97-194, Oct 1997. 12pp.
    (Submitted to J.Cryst.Growth)

    Gadolinium Silicate, GSO

  • ``Applications of GSO:Ce Scintillator to Calorimeters in High Radiation Environment''
    M. Tanaka, K. Hara, S. Kim, K. Kondo, H. Takano, M. Kobayashi, H. Ishibashi, K. Kurashige, K. Susa, M. Ishii ( NIM A404, 1998, 283)