The cross section for the production of single top quarks in the t channel is measured in proton-proton collisions at 13TeV with the CMS detector at the LHC. The analyzed data correspond to an integrated luminosity of 2.2fb -1. The event selection requires one muon and two jets where one of the jets is identified as originating from a bottom quark. Several kinematic variables are then combined into a multivariate discriminator to distinguish signal from background events. A fit to the distribution of the discriminating variable yields a total cross section of 238+-13(stat)+-29(syst)pb and a ratio of top quark and top antiquark production of Rt-ch.=1.81+-0.18(stat)+-0.15(syst). From the total cross section the absolute value of the CKM matrix element Vtbis calculated to be 1.05+-0.07(exp)+-0.02(theo). All results are in agreement with the standard model predictions.