The WUW ML bundle detector: A flow through detector for α-emitters

Using conventional laboratory ware, we designed and manufactured a flow through cell for monitoring α-bearing solutions. The cell consists of a bundle of thermoplastic, transparent tubes coated with a thin layer of the meltable scintillator MELTILEXTM at the inner surface. With appropriate energy windows set, the detector can suppress β-particles to a great extent due to its geometrical dimensions. For pure α-solutions, the detection limits are 5 Bq/ml, for composite nuclide mixtures, the detector is capable to monitor the decontamination of medium active waste (≤107 Bq/ml) down to 100 Bq α/g solution. At a throughput of 1 ml/s, the pressure build-up amounts to ∼2 bar. We have developed a quality control program to ensure the regularity of the individual bundle loops.