  The precision measurement of $K^{+} \rightarrow \pi^{+} \nu \bar{\nu}$ at the
NA62 experiment requires a kaon identification detector to have a time
resolution better than 100ps, at least 95% kaon identification efficiency, and
a pion misidentification probability of less than $10^{-4}$. Since the start of
NA62 data taking in 2016, kaon identification has been performed by a
differential Cherenkov with achromatic ring focus (CEDAR) detector with a
nitrogen gas radiator. A new CEDAR using hydrogen (CEDAR-H) as a radiator gas
has been developed to reduce the material in the beamline, reducing the beam
particle scattering within the detector. CEDAR-H was validated during a
two-week test beam at CERN in 2022 and was approved by the NA62 collaboration
for use in data taking from 2023. The test beam results, installation and
commissioning in the NA62 beamline are reported.
