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Consortium of the 18SIB04 QuantumPascal Project

Towards quantum-based realisations of the pascal

NMIs (National Metrology Insitutes):


PTB (Germany) operates primary pressure standards from 10-10 Pa to 7.5 MPa. It has expertise in optical detection of pressure by means of refractometry and absorption spectroscopy. Its temperature section has expertise in accurate thermalisation and thermometry using fixed-point cells with uncertainties as low as 100 µK and in the dielectric detection methods used in the Boltzmann project for a final uncertainty of 1.9 ppm.

CEM (Spain) provides capabilities, competence, and expertise within the fields of pressure (balance primary standard (10 kPa to 1 MPa), force-balanced piston gauge (0.5 Pa to 15 kPa)) and laser interferometry. Their main interest in this project concerns experimental work on FP cavity-based refractometry and its comparison with current pressure standards.

CNAM (France) provides a broad background in absolute helium-based refractometry. Within this project, CNAM intends to improve their refractometer, in terms of temperature assessment and stability of the pressure in cavity, to make it a primary and/or transfer standard of pressure. CNAM’s temperature department also has considerable expertise in projects related to the measurement of the Boltzmann constant via acoustic thermometry, superconducting microwave cavities and development of cryostats for superconducting cavities.

IMT (Slovenia) has developed special facilities and experience within the EMRP IND12 and EMPIR 14IND06 project for measuring kinetics of gas absorption and desorption in solid materials. This will be used to study permeation of gas in the cavity spacer material and, if necessary, also in other construction materials for new photon-based pressure standards. Being active for more than 30 years in R&D in different fields of vacuum technology, including small sealed ultrahigh vacuum devices like image intensifiers and photomultipliers, IMT accumulated broad knowledge on vacuum materials and processing for reduction of outgassing.

INRiM (Italy) provides a broad background in primary pressure standards in the range from 10-6 Pa to 108 Pa and has long-established and leading expertise in conducting primary thermometry experiments with different methods, particularly acoustic gas thermometry and refractive index gas thermometry. INRiM also has extensive experience in high-resolution interferometry and refractometry and will mainly contribute to this project by developing primary pressure standards which are operated at optical and microwave frequencies.

LNE (France) provides capabilities, competence, and expertise within the fields of pressure balance primary standards (10 kPa to 1 MPa) and force-balanced piston gauges (0.5 Pa to 15 kPa). Their main interest in this project concerns comparisons with novel primary standards.

RISE (Sweden) has extensive experience in FP cavity-based refractometry, including instrument and method development. RISE together with UmU has developed several iterations of state-of-the-art refractometry systems based on fiber-lasers with a wavelength of 1.5 µm which utilise gas modulation methodology. Part of this development has taken place within the scope of the 14IND06 pres2vac project. This includes a system that is based at RISE, which is designed and built to be globally transportable to allow for intercomparisons. Furthermore, RISE also has extensive experience and well-equipped NMI-laboratories for relevant conventional methods within the fields of pressure, vacuum, and temperature, including pressure balances, a force-balanced piston gauges of FPG and FRS type, and two static expansion systems.

Academic and research institutions:

FBK (Italy) has competence and expertise within the field of ab-initio calculations of virial coefficients of non-degenerate quantum atomic and molecular gases with no uncontrolled approximation using path integrals. Their main interest in this project concerns extending this numerical approach to the calculation of dielectric properties of non-degenerate quantum gases, particularly the third dielectric virial coefficient for which no computational method is currently available.

UCL (UK): The group of atomic and molecular physics of the University College London has world leading competences and expertise with highest accuracy calculations, as demonstrated in the ExoMol project. They are experts in the variational solution of Schrödinger equation, ab-initio calculations of the dipole moment surface, and the potential energy surfaces. Their main contributions to this project are theoretical CO and CO2 spectra with sub-permil accuracies.

UmU (Sweden) has extensive competence and solid expertise within the field of laser-based spectroscopic measurement techniques for ultra-sensitive trace gas detection, in particular techniques based on optical cavities, laser locking, and modulation, and within the field of FP-based refractometry, the latter for assessment of gas number density and pressure. UmU is the inventor of the GAMOR (gas modulation) technique. It also has experience in the construction of portable refractometers. Its main interest in this project concerns highly accurate FP-based refractometry systems in general and those based on GAMOR in particular.

UW (Poland) has capabilities, competence, and expertise within the fields of: full configuration interaction and coupled cluster electronic structure calculations, Slater orbitals, explicitly correlated wave functions, relativistic and QED (quantum electrodynamic) effects, and scattering calculations. The contribution to the project concerns accurate calculations of He and Ar atomic and collision-induced polarisabilities; atomic magnetisabilities, dispersion of atomic polarisabilities; three-body collision-induced-polarisability of He, analytic second-order dielectric virial coefficients, and semi-classical third dielectric virial coefficients unsing their computational infrastructure and supercomputers.

Industrial Partner:

WIKA (Germany) is a manufacturer of pressure sensors, pressure controllers, and primary standards based on the fundamental method of a deadweight tester. Furthermore, WIKA hosts a global network of calibration laboratories. They have more than 50 years of experiences in the field and approximately 10000 employees worldwide. They also represent the industrial needs as they are a member of the board of directors of the German Calibration Service DKD.

Collaborating Institutes:

Hong Kong University of Science and Technology | Xi'an Jiaotong University (China) will provide independently calculated theoretical gas parameters like the dielectric virial coefficients of helium, neon and argon.

National Institute of Metrology of China | NIM (China): The working group 'Pressure and Vacuum' of NIM has performed FEM simulations and set up a dual Fabry-Pérot resonator for the realisation of the Pascal.

University of Prishtina (Kosovo): The Department of Physics has developed a quadrupole mass spectrometer-based setup to obtain independent values ​​for the temperature dependence of the gas permeability and solubility of potential spacer materials.