Projects: Sample Environment Group
Development of Sample Environment with Integrated Neutron Focussing
The aim of the project is to increase the signal-to-noise ratio for tiny samples inside different sample environment systems. The goal will be achieved by means of a new device for focusing neutrons.
Miniaturised neutron optical lenses are developed, which are directly integrated into the neutron scattering sample environment. This work is a joined effort between the neutron optics group and our group in LDM, and as industrial partner SwissNeutronics AG.
Contact: M. Bartkowiak / U. Filges
A Novel Device for Neutron Polarization Analysis
We are developing a novel neutron spin filter for longitudinal polarization analysis in magnetic small-angle neutron scattering. It is based on the strong spin dependence of the neutron scattering on protons, is small and works in inhomogeneous fields. The necessary large proton polarization in a single crystal of naphthalene doped with deuterated pentacene is created with a recently developed method of dynamic nuclear polarization (DNP) that uses photo-excited triplet states and requires only moderate experimental means. This allows designing a compact setup with a large acceptance angle that is comparable to 3He spin filter setups, but significantly more compact.
By fully exploiting the advantages of the triplet DNP technique, we achieve record polarization values of 80% at a field of 0.36 T using a simple helium flow cryostat for cooling. The extremely long relaxation times allows polarizing the filter ex situ in the laboratory under optimum conditions and then transferring it to the neutron beamline where it can be operated during several days with almost constant polarization while requiring only a minimum of equipment. Relaxation times of T1 ~ 800 h are achieved at a field of 20 mT and the polarization can be reversed by adiabatic fast passage with an efficiency of above 99%.
This instrument significantly expands the possibilities of the SANS instruments at SINQ at PSI enabling experiments in the field of magnetism so far not possible.
This work is supported by the Swiss National Science Foundation under Grant No. 200021_165496.
Contact: Y. Quan / P. Hautle
Investigation of the Quantum and Vortex Phases in Heavy Fermion Compounds
Strong electronic fluctuations give rise to ground states that are governed by quantum fluctuations. In heavy-fermion systems, the strong coupling between magnetic moments and conduction electrons, and the competition between localisation and itinerancy leads to novel magnetic or superconducting phases that occur in the vicinity of quantum critical points.
Within this project we study the complex interplay between magnetism and superconductivity in the in the family of rare earth-CoIn5 systems.
This work is supported by the Swiss National Science Foundation under Grant No. 162671.
Contact: J. Shen / D. Tartarotti Maimone / M. Bartkowiak
Development of Novel Sample Manipulators for Ultra-Low Temperatures
For Neutron scattering experiments at ultra-low temperatures the thermal response of the sample as well as the cryostat increase. Subsequently, sample equilibration as well as the cooling and warming of the cryostat occupy a sizable part of the measurement time. Moreover, the use of complex sample environment, such as cryo-magnets, call for the possibility to reorient and align of the sample inside the running sample environment.
We develop a miniature low- temperature goniometer, which will allow for a reorientation of samples at ultra-low temperatures. This work is supported by the European Union in the SINE2020 program.
Contact: M. Bartkowiak
Development of a Sample Environment Communication Standard Protocol SECoP
In collaboration with other large scale facilities, we develop a protocol of communication to promote shared developments and industrial standards (SECoP). This protocol allows European facilities to reduce their development costs and share expensive equipment, used at various beamlines. It will define the communication standard of future equipment supplied by scientific and industry-based users.
This work is supported by the European Union in the SINE2020 program and the International Society for Sample Environment ISSE.
Contact: M. Zolliker
Automatisation of Sample Environment Equipment
Computer control for the sample environment devices are under continuous development. The main goals are a secure operation of all devices, user-friendly access to all electronically available parameters, remote access from the office and from outside PSI, recording of all relevant parameters, and easy installation of devices on the beam lines.
Contact M. Zolliker