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A 2nd-generation gravitational neutron spectrometer

The GRANIT project consists of designing and building a second-generation gravitational neutron spectrometer with ultra-high resolution. Its key property is the storage of UCN in a selected gravitationally bound state for extended period of time using a closed specula trap. The high quality of mirrors needed for the trap is at the edge of modern technology.

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Instruments & Support : Instruments & groups > GRANIT > Description

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Granit - A 2nd-generation gravitational neutron spectrometer

The existence of quantum states of matter in the gravitational field has been demonstrated for the very first time at the ILL by a series of ground-breaking experiments with ultracold neutrons (UCN). The GRANIT is the follow-up project based on a second-generation UCN gravitational spectrometer with ultra-high energy resolution. It will provide more accurate studies of/with the quantum states as well as measurements of the resonant transitions between them. It will benefit from a dedicated UCN source delivering UCN to GRANIT with no significant dilution of the phase-space density.


Particle physics and fundamental interactions, e.g.:

  • refined measurement of the electrical charge of the neutron ; Spin-dependent or spin-independent short-range forces ; The search for the axion ; The search for other additional forces beyond the standard model

Foundations of quantum mechanics, e.g. loss of quantum coherence
Solid-state physics
Experimental techniques and their possible technological applications.

Instrument layout

The GRANIT spectrometer will be a unique tool for carrying out a wide range of investigations in particle fundamental physics (neutron electric charge, spin-dependent or spin-independent short-range forces), foundations of quantum mechanics, in surface physics, as well as for development of experimental techniques and their applications.

By 2009, GRANIT was being buit in the framework of ANR (Agence Nationale de la Recherche, France) received by a joint collaboration ILL-LPSC-LMA. The physical program to be carried out involves a number of scientific institutions from France, USA, Germany, and Russia.