Reference instruments based on spectrometric measurement with Lucas Cells.

The Bundesamt für Strahlenschutz (Berlin, Germany) and the Paul Scherrer Institute (Villigen, Switzerland) both operate accredited calibration laboratories for radon gas activity concentration. Both the institutions use Lucas Cells as detector in their reference instrumentation due to the low dependence of this detector type on variations in environmental conditions. As a further measure to improve the quality of the reference activity concentration, a spectrometric method of data evaluation has been applied. The electric pulses from the photomultiplier tube coupled to the Lucas Cells are subjected to a pulse height analysis. The stored pulse height spectra are analysed retrospectively to compensate for fluctuations in the electric parameters of the instrumentation during a measurement. The reference instrumentation of both the laboratories is described with the respective spectrum evaluation procedures. The methods of obtaining traceability to the primary calibration laboratories of Germany and Switzerland and data of performance tests are presented.

Using gaseous emissions of a proton accelerator facility as tracer for small-scale atmospheric dispersion.

The gaseous effluents of the proton accelerator facility located in the Western part of the Paul Scherrer Institute, Aargau, Switzerland, contain a mixture of positron emitters (50 % (15)O, 20 % (13)N and 30 % (11)C). For the experimental verification of a future upgrade of the dispersion model in the complex topography of the Aare valley, a measuring campaign using three continuous gamma-spectrometric measuring stations was launched in 2011. The concept of a modified man-made-gross-count (MMGC) ratio yields a clear signal associated with the positron emitters while minimising the influence of radon progeny rain-out events. A dependence of the measured MMGC ratios on the emitted activity and wind direction could be demonstrated using frequency distributions of the modified MMGC ratio measured in 2012 and 2013. A significant fraction of high MMGC-ratio values was found associated with dispersion directions (based on measurements of the wind direction in 70 m above ground) not towards or even against the direction between stack and measuring station.

Therapeutic stations and the chronically treated mentally ill.

Readmissions to mental hospitals are often cited as evidence of the failure of the contemporary mental health system. This essay proposes a different interpretation of readmission. Building on fieldwork and participant observation methods, the authors argue that the "veteran" patient is less a victim of poor psychiatric care and misdirected reform than he is a citizen with few personal resources, using public services to cope with the exigencies of life. Lacking family, job, and income, the ex-patient incorporates the hospital and other "therapeutic stations" into a resource pool upon which he or she can call when the need arises. The essay also discusses the implications of these findings for assessments of the community mental health movement.