  The upgrades of the CMS and ATLAS experiments for the high luminosity phase
of the Large Hadron Collider will employ precision timing detectors based on
Low Gain Avalanche Detectors (LGADs). We present a suite of results combining
measurements from the Fermilab Test Beam Facility, a beta source telescope, and
a probe station, allowing full characterization of the HPK type 3.1 production
of LGAD prototypes developed for these detectors. We demonstrate that the LGAD
response to high energy test beam particles is accurately reproduced with a
beta source. We further establish that probe station measurements of the gain
implant accurately predict the particle response and operating parameters of
each sensor, and conclude that the uniformity of the gain implant in this
production is sufficient to produce full-sized sensors for the ATLAS and CMS
timing detectors.
