Startup of the high-intensity ultracold neutron source at the Paul Scherrer Institute

Abstract

Ultracold neutrons (UCN) can be stored in suitable bottles and observed for several hundreds of seconds. Therefore UCN can be used to study in detail the fundamental properties of the neutron. A new user facility providing ultracold neutrons for fundamental physics research has been constructed at the Paul Scherrer Institute, the PSI UCN source. Assembly of the facility finished in December 2010 with the first production of ultracold neutrons. Operation approval was received in June 2011. We give an overview of the source and the status at startup.

The neutron Electric Dipole Moment experiment at the Paul Scherrer Institute

“…The nEDM search is therefore an interesting probe for physics beyond the SM. At the new UCN source at the Paul Scherrer Institute (PSI) [3], our collaboration aims at improving the nEDM sensitivity by at least one order of magnitude in the next ten years. The experiment is at room temperature using UCNs in vacuum.…”

A prestorage method to measure neutron transmission of ultracold neutron guides

“…The green vessel displays the container for the solid deuterium used for UCN production. All the shown parts are contained in a large vacuum tank [5,6] …”

“…The first meter of each of the three UCN guides at the PSI UCN source, dubbed "TA", is made of hand-polished and NiMo coated stainless steel [5,7]. It also contains a DLC-coated UCN butterfly valve shown in Fig.8 which can control the neutron flux towards the experimental area.…”

“…The ultracold neutron source at PSI [3][4][5][6][7] is now in normal operation. About ten meters of neutron guides are necessary to transport UCN from the intermediate storage vessel to one of the three beam ports, traversing the several meter thick biological shield.…”

An ultracold neutron storage bottle for UCN density measurements

“…At the Paul Scherrer Institute (PSI), Villigen, Switzerland a new UCN source was constructed and has been in operation since 2011 [19][20][21][22].…”