X-ray fluorescence analysis of metal distributions in cryogenic biological samples using large-acceptance-angle SDD detection and continuous scanning at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III.

C Rumancev,T Vöpel,B König,A R Von Gundlach,G Falkenberg,A Rosenhahn,J Garrevoet,W H Schroeder,L Jolmes,A Gräfenstein,S Ebbinghaus,T Senkbeil,S Stuhr

doi:10.1107/s1600577519014048

Abstract

A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor-field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s-1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof-of-principle measurements using continuous-movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system.

Highlights

Nano- and microprobe X-ray fluorescence (XRF) analysis at synchrotron sources provides access to map and visualize the distribution of chemical elements in biological samples and is a technique commonly used in biology and medicine (Paunesku et al, 2006; Borjesson et al, 2003)
A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany
The Rococo 2 detector was implemented in the cryogenic vacuum chamber to improve the sensitivity for XRF microscopy

Summary

Introduction

Nano- and microprobe X-ray fluorescence (XRF) analysis at synchrotron sources provides access to map and visualize the distribution of chemical elements in biological samples and is a technique commonly used in biology and medicine (Paunesku et al, 2006; Borjesson et al, 2003). It was applied for in vitro measurements of lead in bones (Todd & Chettle, 1994) and to detect trace element distribution in plants (Punshon et al, 2009).

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