A dedicated small-angle X-ray scattering beamline with a superconducting wiggler source at the NSRRC.
At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5 GeV storage ring, a dedicated small-angle X-ray scattering (SAXS) beamline has been installed with an in-achromat superconducting wiggler insertion device of peak magnetic field 3.1 T. The vertical beam divergence from the X-ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (DeltaE/E approximately 2 x 10(-4)) in the energy range 5-23 keV, or by a double Mo/B4C multilayer monochromator for 10-30 times higher flux ( approximately 10(11) photons s(-1)) in the 6-15 keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of approximately 0.9 mm x 0.3 mm (horizontal x vertical) at the focus point located 26.5 m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing-incidence SAXS (GISAXS) from liquid surfaces. Two online beam-position monitors separated by 8 m provide an efficient feedback control for an overall beam-position stability in the 10 microm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray-tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core-shell quantum dots) and GISAXS from liquid surfaces.
Liu
Din Goa
DG
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
Chang
Chien Hung
CH
Liu
Chin Yen
CY
Chang
Shih Hung
SH
Juang
Jwei Ming
JM
Song
Yen Fang
YF
Yu
Kuan Li
KL
Liao
Kuei Fen
KF
Hwang
Ching Shiang
CS
Fung
Hok Sum
HS
Tseng
Ping Chung
PC
Huang
Chi Yi
CY
Huang
Liang Jen
LJ
Chung
Shih Chun
SC
Tang
Mau Tsu
MT
Tsang
King Long
KL
Huang
Yu Shan
YS
Kuan
Chien Kuang
CK
Liu
Yi Chih
YC
Liang
Keng S
KS
Jeng
U Ser
US