The Humidity Control Device @EMBL/ESRF


Description: HC1b003_2_composed.tifDescription: DSC06567_new




The HC1 is actually in use at the EMBL/ESRF MX beamlines ID14-1, ID23-1, ID23-2 and BM14. If you’d like to carry out the experiments on another beamline please contact Matthew Bowler (


Preparing your experiment

In order to prepare your experiment before coming to the ESRF please take into account the following: 


·         Crystals must be brought in plates or crystallised onsite (a 20°C crystallization room is available at ID14 user’s lab).

·         Crystals that have been cryo-cooled already are not suitable for dehydration experiments

·         A good stock of crystals is necessary.

·         Crystals have to be stable between 20 and 25 °C (experiments are carried out at room temperature).

·         The crystallisation condition cannot include high amounts (>15%) of volatile compounds.

·         Extremely delicate crystals (photosensitive, O2 sensitive, radiation sensitive ...) may have problems.

·         Mesh loops (from Mitegen or MDL) are used to mount the crystals.

·         It is desirable that crystals have enough scattering power to be able to index the image/s.


Using the device

·         Check the relative humidity (RH) of the crystallization condition using this form.

·         Set this RH value and mount a crystal with a mesh loop.

·         Remove the excess of mother liquor that surrounds the crystal with a wick.

·         Take a diffraction image to characterize the initial state (space group, unit cell, mosaicity, etc).

·         Decrease the RH value in steps of 1%, letting the crystal equilibrate between steps (5 minutes approx.) and taking a diffraction image to compare with the previous ones.

·         In the case where an improvement is observed, further optimization will be needed.

A full description of the HC1 software and the user’s manual is available. If you need further information please contact Matthew Bowler (



We support users of the HC1 throughout the dehydration experiments. We can also provide expertise based on our database and statistics tools (see feedback). We ask experienced users that don’t need to be assisted to inform us in advance.



Once the experiment is finished you will receive a survey form that we ask you to complete. This information will be stored in our dehydration experiments database and will allow us to provide better support in the future.