SAXS Laboratory Instrumentation J. D. Londono DuPont Experimental Station Wilmington DE

Lab Instrumentation Safety Pinhole instrument Increasing intensity Laboratory setup Pinhole instrument Increasing intensity Use of multilayer optics Rotating anode source Kratky Instrument Increasing resolution Bonse Hart Instrument (Jan Ilavsky)

Safety; Lab Setup (1) Controlled temperature and atmosphere to protect high voltage electrical equipment Nominally 50% humidity, 73ºF Avoid being above the dew point May cause condensation and dripping Avoid being too dry May cause electrical discharges May need dedicated air conditioning/humidifier Floor strength must support heavy analytical equipment

Safety; Lab Setup (2) Hazardous conditions created by cooling water in combination with high voltage x-ray equipment X-ray tube needs 1 gal/min cooling flow Rotating anode needs 6 gal/min (18KW) A cooling tank is about 30 gallons in capacity Cooling capacity in a lab may reach a total of ~20 gal/min and several tanks totaling ~100 gal Sound safety strategy is to separate water tanks from the high voltage equipment Locate tanks in a basement if possible X-ray safety Radiation badges, interlocks, process safety management and hazard analysis

The Pinhole Instrument SAXS Camera at MRL UCSB A B C Source to sample and sample to detector distances are often the same path lengths are evacuated The pinholes (4) are located near the source (A) and near the sample (C), and the beam defining pinhole (B) is located half-way between source and sample A (400m), B (200m), C (700m) Beamstop is a pin diode used to measure transmitted beam

Examples of Commercial Pinhole Cameras Purdue University Rigaku Bruker

Increasing Intensity Use of multilayer optics Rotating anode source Kratky Instrument

Use of Multilayer Optics Bragg scattering from controlled alternating layers of light/heavy element materials is used to produce focused or parallel beams If the layer thickness is varied across a pre-curved substrate, a graded optic can be produced that captures a larger angle of X-rays from the source and produces either a focused or parallel X-ray beam.

Rotating Anode Source A clean well-serviced anode is the key to its flawless operation The cathode fails after about 1000 hours of operation

Kratky Instrument A Krakty instrument is a viable way to obtain reasonable intensity at a low cost Kratky instruments generally run on a x-ray tube source Data has to be desmeared because of the use of line collimation