  To measure the main characteristics of radiative neutron decay, namely its
relative intensity BR (branching ratio), it is necessary to measure the spectra
of double coincidences between beta-electron and proton as well as the spectra
of triple coincidences of electron, proton and radiative gamma-quantum.
Analysis of double coincidences spectra requires one to distinguish events of
ordinary neutron beta decay from the background; analysis of triple
coincidences relies on distinguishing radiative neutron decay from background
events. As demonstrated in our first experiment, these spectra presented a
heterogeneous background that included response peaks related to the
registration of electrons and protons by our electronic detection system. The
NIST experimental group (emiT group) observed an analogous pattern on the
spectrum of double coincidences. The current report is dedicated to the
analysis of this heterogeneous background. In particular, this report
demonstrates that the use of response function methodology allows to clearly
identify radiative neutron decay events and to distinguish them from the
background. This methodology enabled us to become the first team to measure the
relative intensity of radiative neutron decay B.R.= (3.2+-1.6)*10-3 (where
C.L.=99.7% and gamma quanta energy exceeds 35 kev). In addition, the review
emphasizes that the background events on the spectrum of double coincidences
are caused by ion registration, and demonstrates that one cannot ignore the
ionic background, which is why experiment registered the ions and not recoil
protons.
