21B2　U90 - Gas Phase

Abstract

The BL21B beamline is an ultra-high resolution and high flux U9 cylindrical grating monochromator (U9-CGM) beamline, covering the photon energies from 5 to 100 eV. Two energy branches using separate entrance slits and incident angles are used to optimize the overall performance. The low energy branch with grating included angle of 150° covers photon energies from 5 to 30 eV. The high energy branch with grating included angle of 130° provides energy range from 15 to 100 eV. Movable entrance and exit slits are used to enhance the beamline performance. The energy resolving power with both slit openings set at 10 μm is 100000 at 16 eV. Photon fluxes of 2 × 10¹⁰ and 1 × 10¹¹ photons/sec/200mA are obtained at the energy resolving power of 100000 and 40000, respectively.

Areas of Research

Ultra-high resolution UPS, atomic and molecular spectroscopy, surface science.

Light Source

Type	Undulator
Source Size	120 μm × 60 μm (V × H)
Source Emittance	ξx = 2 × 10^-8 mrad
	ξy = 2 × 10^-8 mrad
Period Length	9 cm
Number of Periods	48
Energy Range	5 ~ 500 eV
Brilliance	10¹⁶ ~ 10¹⁷ (photons/sec/mm2/mrad2/0.1%BW/200mA)
Power	P_T = 3850 W, P_cen = 599 W