February Status Update

New Hardware and Software for Annealing Crystals

For users who need wish to anneal their crystals, NE-CAT has installed a ‘Cryo-Shutter’ which cuts offs the liquid nitrogen stream from the sample.  Annealing should only be performed on fresh crystals which have not been irradiated.  Due to the intensity of the beam at the APS, exposure of cryogenically frozen crystals to x-rays results in the creation of hydrogen.  When crystals are defrosted, the hydrogen is explosively released as gas, resulting in bubbles in the cryosolution, or in more extreme cases, utter decimation of the crystal.  For local users, the cryo-shutter controls can be accessed through the sample changing or robot menu on the sample centering tab of the Auxiliary script.  Implementation of commands to control the cryo-shutter during remote data collection is in progress.

Fig. 1 The cryo-shutter in the closed position.

Fig. 2  The cryo-shutter in the open position.

Automounter High-Capacity Dewar Progress

Work continues on the high-capacity dewar for the new sample automounter.  The dewar is designed to  hold up to 14 pucks.  Here is a photo of the high-capacity dewar at the end of February 2014.

Fig. 3  High-capacity dewar in the dry lab.

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