A spectrometry instrument with exchangeable accessories (34, 48, 50, 52)
providing, for example, different sample presentation facilities. The
accessories include a manually operable cam-lock facility (54, 68) for
quick and easy attachment of an accessory to the instrument. The
instrument also includes an electrical circuit (86-90), which is completed
by a circuit portion (100) in an accessory when the accessory is attached
to the instrument, for generating a unique identifying voltage (94) to
thereby identify that accessory. This allows for automatic loading in a
controlling computer of programs for setting up and running the instrument
for measurement regimes using that accessory. The spectrometry instrument
is preferably a spectrophotometer used for phosphorescence decay
measurements in which sequential phosphorescence emission measurements
data from each of a number of excitation cycles applied to a sample are
taken and then reassembled into a correct time sequence to define a
phosphorescence decay characteristic for the sample, that is, measured
data points from a second (and subsequent) excitation cycle are
interleaved with those from a first excitation cycle. This significantly
reduces the time for establishing a phosphorescence decay characteristic.
