The European NORM Association (ENA)-promoting radiation protection in the field of norm in Europe.

The European NORM Association (ENA) was founded in 2017, merging previously informal European networks. It has the statute of an International Non-profit Organization established under Belgian Law. The objective of ENA is to promote and advance radiation protection in the context of exposure to NORM.

Liquid helium-free cryostat and hermetically sealed cryogenic microwave cavity for hyperfine spectroscopy of antiprotonic helium.

The design and properties of a new cryogenic set-up for laser-microwave-laser hyperfine structure spectroscopy of antiprotonic helium - an experiment performed at the CERN-Antiproton Decelerator (AD), Geneva, Switzerland - are described. Similar experiments for (4)He have been performed at the AD for several years. Due to the usage of a liquid helium operated cryostat and therefore necessary refilling of coolants, a loss of up to 10% beamtime occurred.

First observation of two hyperfine transitions in antiprotonic He.

We report on the first experimental results for microwave spectroscopy of the hyperfine structure of p¯3He+. Due to the helium nuclear spin, p¯3He+ has a more complex hyperfine structure than p¯4He+, which has already been studied before. Thus a comparison between theoretical calculations and the experimental results will provide a more stringent test of the three-body quantum electrodynamics (QED) theory.

Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio.

Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic helium (pHe(+)) is a three-body atom consisting of a normal helium nucleus, an electron in its ground state and an antiproton (p) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n ≈ l + 1 ≈ 38.