MIRA * is a high sensitive μ-HPLC radioactivity flow detector. In μ-HPLC-applications the eluate flow rate is very small which optimally requires very small flow cells with almost no dead volume. Conventional radioactivity flow detectors have been modified for small dead volume and small cell volumes. Consequently, the radioactivity counted in the flow cell is very small and often impossible to detect in the background. Therefore, MIRA* has been developed using quite small photomultipliers with very low noise. The small photomultipliers are arranged in coincidence to obtain the best possible sensitivity. 4 coincidence detectors are arranged one after another. The very small radioactive fraction is passing one detector after the other, each coincidence flow detector is counting separately over the optimal interval time. 4 separate radio-chromatograms are digitally recorded and are displayed on the PC. The flow time from one flow cell to the following one is automatically determined. When the delay of the 4 consequent flow detectors are digitally compensated, the 4 radio-chromatograms can be added up. This dramatically improve sensitivity and fractions which are not detectable in a single coincidence flow detector can be obtained by MIRA*. In PC-controlled HPLC systems the sensitivity gain can be monitored live and is even more impressive.
MIRA* can be supplied with internal solid scintillators as well as with liquid scintillator admixture.