Open AccessMeasurement of the two‐photon correlation of synchrotron radiation in the VUV region by a delay‐time modulation technique
Author(s) -
Takayama Yasuhiro,
Shiozawa Hidetsugu,
Yoshida Tetsuo,
Lee Chol,
Obu Kenji,
Otsubo Hideo,
Miyahara Tsuneaki,
Yamamoto Shigeru,
Ando Masami
Publication year - 2003
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049503009361
Subject(s) - physics , photon , optics , discriminator , synchrotron radiation , signal (programming language) , amplitude , coherence time , coherence (philosophical gambling strategy) , synchrotron , laser , detector , quantum mechanics , computer science , programming language
The two‐photon correlation (second‐order coherence) of synchrotron radiation in the VUV region ( = 55 eV) has been measured using a novel photon‐counting method. A new technique has been developed to measure a small bunching effect by using a coincidence unit composed of a constant fraction discriminator, a time‐to‐amplitude converter (TAC), a single‐channel analyzer (SCA) and two solid‐state switches. The path of the circuit through which the stop signal for the TAC passes can be changed by a control voltage generated by a function generator, and the relative arrival time of two photons on condition that the output signal from the SCA appears is consequently changed. By modulating the arrival time and measuring the output rate from the SCA with a digital lock‐in amplifier, an apparent bunching effect has been observed which is characteristic of the chaotic light. The electron‐beam emittance in the horizontal direction was estimated as nm rad by this experiment, and the value was consistent with the designed value of 36 nm rad.