By Michael Banks

Neutron scientists in Europe are facing a number of headwinds in the coming decade. One is the uncertainty caused by the recent UK vote to leave the European Union. Another is the impending closure of ageing reactors across the continent such as the Orphée reactor in Paris and the BER II reactor in Berlin, which could both shut down by 2020.

A recent report by an expert group of researchers – the Neutron Landscape Group – paints a worrying challenge for neutron scientists. It forecasts that the continent’s supply of neutrons could drop by as much as a half over the next decade – a shortfall in capacity that is unlikely to be met by the upcoming European Spallation Source in Lund, Sweden.

That said, there are plans to help overcome the impending neutron gap, including proposals to plug it by building compact, specialist sources. Improvements to accelerator technology and instruments could also help by boosting the number of usable neutrons. Scientists at the US Spallation Neutron Source, for example, are pioneering a method to improve its proton beam energy using plasma processing, while the National Institute of Standards and Technology’s world-leading neutron microscope will soon open up to users.

Here is a rundown of what is in the 2016 focus issue on neutron science.

• Plugging the neutron deficit – Compact neutron sources could stave off the decline caused by the closure of European facilities, as Jon Cartwright reports

• Towards a neutron microscope – Matin Durrani travels to the National Institute of Standards and Technology to find out about the world’s most advanced neutron microscope

• Looking beyond Brexit – Mark Johnson stresses that the UK’s recent decision to leave the European Union must not affect neutron science on the continent

• Plasma boost for particle acceleration – Edwin Cartlidge discovers how scientists at the US’s Spallation Neutron Source are using “in situ plasma processing” to clean contaminated accelerator cavities onsite

• Breaking new ground – An upgrade to a neutron source at the Joint Institute for Nuclear Research will boost its neutron flux, as Ned Stafford explains

• From neutrons to neutrinos – David Burman looks at a proposal to modify the European Spallation Source’s linear accelerator to produce an intense beam of neutrinos

• Events diary – Conferences, schools and workshops in the neutron-science calendar

All full members of the Institute of Physics received a print edition of the focus issue along with their copy of the October issue of Physics World. You can also read the focus issue free of charge on your desktop or on any iOS or Android smartphone or tablet via the Physics World app, available from the App Store and Google Play.

I hope you find this focus issue stimulating and please do let us have your comments by e-mailing pwld@iop.org or leaving your remarks below.