18-22 February 2019
Vienna University of Technology
Europe/Vienna timezone

Direction-Sensitive Dark Matter Search Using Tungstate Scintillator

21 Feb 2019, 09:50
20m
EI8 ()

EI8

Talk Dark matter and other low-background experiments Dark matter and other low-background experiments

Speaker

Shunsuke Kurosawa (Tohoku Universtiy)

Description

Ones of the candidates for the Dark Matters are weakly interacting massive particles (WIMPs), and we expect that the Earth should experience a “wind” (named 'WIMP wind') against the direction of the rotation, where is direction to Cygnus.
In this study, we propose a new type Dark matter detector using single crystals in order to have higher detection efficiency than gaseous ones. Some team reported that ZnWO$_4$ can detect the direction of incident particles due to anisotropic. However, the mechanism has been not revealed. A Mg-admix ZnWO$_4$ crystal is expected to have different lattice constant from normal ZnWO$_4$, and anisotropic properties can be changed. Thus, we compare scintillation and anisotropic properties for ZnWO$_4$ and Mg-admix ZnWO$_4$ in this paper.
We grew ZnWO$_4$ and (Zn, Mg)WO$_4$ single crystals with diameters of ~0.5 inch grown by the Czochralski process. We checked the crystal phase and structure using the powder X-ray diffraction.
Light outputs of the crystals irradiated with 5.5 MeV alpha rays and 59.5 keV X-rays were estimated for each surface (orientation) for ZnWO$_4$ and (Zn, Mg)WO$_4$ using a photo multiplier and an $^{241}$Am source, and the light output ratios ($\alpha$ /$\beta$ ratio), defined as peak channel of 5.5-MeV alpha-ray absorption peak over that of 59.5-keV X-ray, were evaluated.The results show we find anisotropic for both samples, while anisotropic effect for Mg-admix made smaller than Mg-free one.

Primary author

Shunsuke Kurosawa (Tohoku Universtiy)

Co-authors

Hiroyuki Sekiya (University of Tokyo) Mrs Misa Tsukahara (Yamagata University) Mrs Maria Abe Akihiro Yamaji Mr Rikito Murakami (Tohoku University) Mr Takahiko Horiai (Tohoku University) Shohei Kodama (Tohoku University) Mr Yasuhiro Shoji (Tohoku University) Masao Yoshino (Institute for Materials Research, Tohoku University) Dr Yuji Ohashi (Tohoku University) Dr Yuui Yokota (Tohoku University) Dr Kei Kamada (Tohoku University) Prof. Akira Yoshikawa (Tohoku Ubiversity) Prof. Akimasa Ohnishi

Presentation Materials