Kyriakos Tamvakis is a Greek theoretical physicist and professor who has held positions at what European research organization that operates the largest particle physics laboratory in the world?
CERN The European Organization for Nuclear Research (French: "Organisation européenne pour la recherche nucléaire"), known as CERN ( ; ] ; derived from the name "Conseil Européen pour la Recherche Nucléaire"), is a European research organization that operates the largest particle physics laboratory in the world. CERN is an official United Nations Observer. Established in 1954, the organization is based in a northwest suburb of Geneva on the Franco–Swiss border, ( ) and has 22 member states. Israel is the only non-European country granted full membership.
Hermetic detector In particle physics, a hermetic detector (also called a 4π detector) is a particle detector designed to observe all possible decay products of an interaction between subatomic particles in a collider by covering as large an area around the interaction point as possible and incorporating multiple types of sub-detectors. They are typically roughly cylindrical, with different types of detectors wrapped around each other in concentric layers; each detector type specializes in particular particles so that almost any particle will be detected and identified. Such detectors are called "hermetic" because they are constructed so as the motion of particles are ceased at the boundaries of the chamber without any moving beyond due to the seals; the name "4π detector" comes from the fact that such detectors are designed to cover nearly all of the 4π steradians of solid angle around the interaction point; in terms of the standard coordinate system used in collider physics, this is equivalent to coverage of the entire range of azimuthal angle (formula_1) and pseudorapidity (formula_2). In practice, particles with pseudorapidity above a certain threshold cannot be measured since they are too nearly parallel to the beamline and can thus pass through the detector. This limit on the pseudorapidity ranges which can be observed forms part of the "acceptance" of the detector (i.e. the range of phase space which it is able to observe); broadly speaking, the main design objective of a hermetic detector is to maximise acceptance, i.e. to ensure that the detector is able to measure as large a phase space region as possible.