  The main objective of the European Spallation Source (ESS) is to perform
consistently high impact neutron scattering science using the highest neutron
flux of any facility in its class. This ambition is naturally accompanied by
operational challenges related to the vertical integration of the instruments'
hardware and software shared between collaborators from 13 European countries.
The present work will detail integration tests performed at the V20 Test
Instrument at Helmholtz-Zentrum Berlin in Germany. An ESS chopper prototype was
successfully controlled through the ESS Chopper Integration Controller (CHIC)
and Experimental Physics and Industrial Control System (EPICS). Neutron data
were successfully collected and time stamped using neutron beam monitors, the
ESS prototype detector readout electronics and the Data Management Software
Center (DMSC) data acquisition (DAQ) software. Chopper rotation events were
timestamped and the chopper disk showed excellent stability and neutron
absorption characteristics. The test resulted in (i) the expected
time-of-flight (TOF) response, (ii) collected data that compared well with
instrument reference data and (iii) revealing the diagnostic power of the
performed integration tests. The results of this integration test validate the
ESS chopper and detector DAQ architecture choices.
