Page 86 - ILL Annual Report 2019

TECHNICAL AND COMPUTING DEVELOPMENTS
Judith Peters. German
Université Grenoble Alpes, LiPhy, and the ILL
‘I hold a professorship in Physics at the Université Grenoble Alpes and am co-responsible for the IN13 backscattering spectrometer at the ILL. My research interests include dynamical studies of bio-systems
under high-pressure conditions and, in particular, the adaptation mechanisms of lipids, proteins and cells to such harsh environments.’
High-pressure cells and sticks for investigating systems in solution and membrane layers
The number of publications listed in the Web of Science about experiments under high hydrostatic pressure has increased by 50 % over the last ten years, as has the number of pressure experiments performed at the ILL. This shows the scientific community’s increasing interest in this area and the need for suitable equipment.
The new high-pressure cells and sticks available for interested users on many of the ILL’s instruments have been developed in collaboration with the ILL’s Service for Advanced Neutron Environments (SANE).
AUTHORS
J. Peters (UGA, Grenoble, France) E. Lelièvre-Berna (ILL)
ARTICLE FROM
J. Neutron Res. 19 (2017) —doi: DOI 10.3233/JNR-170044 and J. Neutron Res. 20 (2018)—doi: DOI 10.3233/JNR-180055
REFERENCES
[1] F. Meersman et al., Rev. Mineral. Geochem. 75 (2013) 607
[2] R.E. Collins, G. Rocap and J.W. Deming, Env. Microbiol. 12
(2010) 1828
[3] K. Takai et al., Proc. Nat. Acad. Sc. 105 (2008) 10949
[4] A.A. Yayanos, Proc. Nat. Acad. Sc. 83 (1986) 9542
The pressures required for investigating biological systems in solution or membranes are relatively low compared with those required in other scientific domains, as biomolecules are very sensitive to pressure and can undergo unfolding in the range of 400 MPa to 1 GPa (100 MPa = 1 kbar) [1]. However, the range of physico-chemical conditions under which microbial life has been observed is expanding, including metabolic activity at −40 °C [2], cell proliferation at 122 °C [3] and bacteria surviving at 130 MPa [4]. Deep sea hydrothermal vents present one of the most fascinating biotopes on the planet and have been suggested as places where life could have originated. They correspond to extreme conditions
in more than one respect: strong temperature gradients prevail, combined with high pressures and salinity. In order
to shed more light on how life developed, there is a need
to reproduce such conditions in laboratories. It was in this context that new high-pressure equipment has been developed recently at the ILL.
High-pressure sample sticks have to fulfil specific functions, such as protecting the fluids that transmit the hydrostatic pressure to the sample in the cell from freezing. As the sticks are often used in a cryostat or cryofurnace, a cold point can develop close to the central high-pressure capillary. We have designed a stick with a capillary that is thermally isolated from the cryogen bath and heated to a desired temperature (figure 1). The maximum pressure able to be applied remotely to the sample through this stick is 700 MPa, while the sample temperature can be controlled from 1.8 to 550 K. Moreover, the ILL has recently purchased two high-pressure regulators that automatically control and adjust the pressure levels and continuously record the pressure in NOMAD
data files. The equipment has been successfully tested on a number of different instruments with the adequate infrastructure (IN13, IN6, IN5, IN16B and D16). These sample sticks are available with 50 mm and 70 mm diameters and can be booked for experiments.
ANNUAL REPORT 2019