Registration information Participation Rules The school is mainly addressed to the education of PhD and postdoctoral students without prior knowledge of neutron, X-ray and muon techniques. It is fully open to the national and non-national public. English is the school's language. The number of participants is limited to 100. Online registration Please register here online for the 13th PSI Summer School. The registration deadlines are: Early registration fee: CHF 1,100.00 until Wednesday, April 30, 2014 Regular registration fee: CHF 1,200.00 until Monday, June 30, 2014 The number of participants is limited to 100.