Spectrometer for new gravitational experiment with UCN

TL;DR

This paper presents a sensitive gravitational spectrometer for ultra-cold neutrons designed to test the weak equivalence principle by comparing neutron energy gain during free fall to quantum energy quanta, with promising initial results.

Contribution

It introduces a novel gravitational spectrometer for UCNs capable of precise equivalence principle measurements and discusses initial experimental results and potential improvements.

Findings

Collection rate allows gamma measurement with 0.5% uncertainty per day.

Systematic effects identified and partially corrected.

Device potential for improved precision and systematic control.

Abstract

We describe an experimental installation for a new test of the weak equivalence principle for neutron. The device is a sensitive gravitational spectrometer for ultra-cold neutrons allowing to precisely compare the gain in kinetic energy of free falling neutrons to quanta of energy ${\hbar}{\Omega}$ transferred to the neutron via a non stationary device, i.e. a quantum modulator. The results of first test experiments indicate a collection rate allowing measurements of the factor of equivalence $ { \gamma}$ with a statistical uncertainty in the order of $5{\times}10^{-3}$ per day. A number of systematic effects were found, which partially can be easily corrected. For the elimination of others more detailed investigations and analysis are needed. Some possibilities to improve the device are also discussed.