Seminars

Crystal growth, luminescence and scintillation characterization of inorganic single crystal

Date March 22, 2019

Time 4:30 pm

Speaker Dr. Indra Raj Pandey (Kyungpook National University)

Place CUP Meeting room(C185), Experiment Building(1F), IBS

Abstract

A number of crystal growing techniques, such as Czochralski, Bridgeman, Kyropoulos, micro-pulling down, top seeding solution growth, solution growth are used from an earlier time. Among them, Czochralski and Bridgeman are generally used melt-growth technique for growing single crystal scintillators. These methods are used for growing hygroscopic as well as non-hygroscopic scintillating crystals. Using these technique large size single crystal can be grown. The crystal scintillators have applications in various fields such as; rare events search experiments, (dark matter and neutrionless double beta decay), medical imaging, homeland security, dosimetry applications. In order to fulfill the requirements for these applications, the scintillators should have high light yield, low radioactive impurities, matching of the emission spectrum wavelength with the spectral sensitivity curve of the photo detector, good storage material, fast decay time. 

In order to know the new crystals applicability, it is necessary to study the crystals’ luminescence and scintillation properties. The crystals containing Mo and W have wide application in 0νββ decay and dark matter search field. The crystals from different phase Li2O-MoO3, Na2O-MoO3 and Na2O-WO3 phase has been grown with Czochralski techniques. Usually, the Mo-content crystal has very low or no light yield at room temperature. The newly grown crystals Li2MoO4, Na2Mo2O7, Na6Mo11O36 and Na2W2O7 are characterized under the excitation of different energy source (X-rays, γ-rays, 266 nm Laser, 280 nm LED, 90Sr (β) source) from room to 10 K.

A new detection method of gravitational waves

Date March 7, 2019

Time 4:30 pm

Speaker Prof. Il H. Park (SKKU)

Place Conference room(B109), Theory Building(1F), New IBS HQ

Abstract

A neutron star involved gravitation wave, GW170817, was detected by LIGO and VIRGO, and immediately followed by observations of multi-band electromagnetic wave (EM) from 70 observatories over the world and in space. The detection of this event opens a new era of multi-messenger astrophysics(MMA). Similar to the history of EM observations for last decades, multi-wavelength observation of GW would be important to understand the Universe, to name a few, laser interferometry on ground and in space and pulsar timing array. In this talk I will introduce another new way of gravitation wave detection.