Specialty Sample Mounting for CCRs at NCNR 

Tanya Dax, Sample Environment. 

March 10, 2020

 

Neutron Shielding at High Temperature 

For safety reasons, cadmium cannot be used in CCRs above 420 Kelvin. For high 

temperature sample mounting, boronated aluminum and boron nitride are 

good options for neutron masks and sample holders. 

Low Background Thin Film Sample Holder -Prototype 

This sample holder consists of a boronated aluminum base plate and 

clamps, a 6061 aluminum tee, and a boron nitride shell. This allows 

measurement of substrates at SPINS, BT4, and BT7 up to 800 Kelvin. 

There are tradeoffs to this method of sample mounting. The sample’s 

thermal connection to the heater block is poor when compared to 

mounting within a sealed sample container or when using the inner 

and outer heat shields. For samples where the signal is small and the 

temperature behavior is well understood, this tradeoff is worthwhile. 

Sample alignment is more challenging as there is not a goniometer on 

this setup.

This sample holder is a prototype developed with Colin Heikes and Alex Grutter and they have 

successfully tested it at SPINS and BT4. Future iterations will have more fine alignment capability and 

variable height shells. 

Titanium Annular Cans with Gold Seal 

These are exact copies of the aluminum HFBS/NSE annular cans for use in toploading CCRs. There are two applications for this. For high temperature 

measurements where the sample is either air sensitive or has poor physical 

contact with the walls of the sample container, a sealed helium atmosphere is 

possible using the gold gasket instead of indium. It is vital that the sample is 

well characterized offline so it is known that it will not decompose at 

experiment temperatures for this to be a viable option. The other application is 

for samples that corrode aluminum, and again the sample has to be well 

understood offline to know that it will not also react with titanium across the 

full temperature range. These cans also have boron nitride shells designed by 

Antonio Faraone.

 
Flat Plate Electric Field Sample Holder for Powders up to 5kV -Prototype 

This untested prototype was designed for the HFBS top-loading CCR. There are two 6061 aluminum 

plates with a PTFE spacer, to be sealed with indium wire. The sample volume is 1 mm thick and 30 mm

diameter, and there are positions on either plate for wiring in the high voltage circuit. Maximum 

temperature is limited to 420 Kelvin due to the use of indium and 475 Kelvin due to the PTFE.

Electromagnets and CCRs 

The reflectometry and SANS instruments have a 

variety of small electromagnets and one 

superconducting magnet with room temperature 

bores suitable for use with bottom-loading CCRs. Each 

has a different pole spacing, and the reflectometry 

instruments run in a horizontal configuration. The 

narrow bores require long sample rods and narrow 

vacuum tailpieces, and each is unique to the magnet 

it is designed for. Alan Ye has worked extensively to 

optimize these tailpieces, and the latest version 

includes cylindrical single crystal silicon vacuum tails.

SANS cell mounting on CCRs 

The standard SANS titanium cells were not originally designed to be run in a 

CCR. Cedric Gagnon designed a frame that holds two cells side by side to 

mount onto the CCR sample block, with an optional cadmium or boronated 

aluminum mask. The cells were also modified to be sealed with either PTFE or 

indium on both the windows and the fill port and the height is modified to fit 

the frame. 

To accompany this, we have a specialty vacuum can with 5-inch 

silicon windows and a frame for installing the CCR at the SANS 

instruments in a way that allows sample changes without disturbing 

the sample alignment.