Korea Atomic Energy Research Institute

Ki Tae Lee

Young Uk Jeong

Nikolay Vinokurov

Kyuha Jang

Seong Hee Park

Hyun Woo Kim

Jeong Ho Moon

Sangyoon Bae

Boris Gudkov

Shang In Shin

Inhyung Baek

Gudkov Boris

Tae Sik Yoon

Jeong Sang Jo

There is provided an ultrafast electron diffraction apparatus including: a photoelectron gun configured to emit an electron beam; a bending portion for emitting the electron beam emitted from the photoelectron gun by changing a travel direction of the electron beam by a predetermined angle; and a sample portion including a sample to be analyzed by the electron beam emitted from the bending portion. The electron beam reaches the sample portion in a state that a pulse of the electron beam is compressed and the timing jitter between the pumping light and probe electron pulse is completely reduced as the travel direction of the electron beam is changed by the predetermined angle through the bending portion.

Ultrafast electron diffraction apparatus

A modulator includes: a high voltage transformer transforming a voltage supplied through a primary side and a secondary side to apply a current pulse to a driving device; a bipolar pulse generator applying a magnetizing pulse and a main pulse to a connection line connected to the primary side of the high voltage transformer; and a timing controller controlling a time difference of applying the magnetizing pulse and the main pulse, wherein the bipolar pulse generator includes a magnetizing pulse generation unit generating the magnetizing pulse by using positive power, and a main pulse generation unit generating a negative pulse by using negative power. Also, the modulator includes a pulse waveform controller in which a plurality of unit modules of the same structure is disposed in series through a small transformer on the secondary side of the high voltage transformer. These two configurations may independently control the magnitude and the waveform of the current pulse of the high voltage, respectively and realize simultaneously two functions.

Modulator for controlling current pulse and method thereof

Provided is a linearly polarized ultra-short terahertz wave generating device which has a parabolic barrel mirror installed at one side of a multiple thin film, to generate an ultra-short terahertz wave having single linear-polarized light and uniformly formed output distribution.

Device for generating linearly polarized ultra-short terahertz wave

A variable-period permanent-magnet undulator which is applicable not only to a planar undulator but also to a helical undulator, in which permanent-magnets and ferromagnetic substances are alternately arranged, and the ferromagnetic substance interposed between the permanent-magnets is saturated to thus enable the magnets to be effectively spaced apart from each other by the repulsive force between the permanent-magnets, thereby adjusting the period of the magnetic field in an easy and precise manner.

Variable-cycle permanent-magnet undulator

Growing community of inventors

Daejeon, South Korea

Ki Tae Lee