RESUMEN
Re-entrant ionization chambers (ICs) are essential to radionuclide metrology and nuclear medicine for maintaining standards and measuring half-lives. The requirements of top-level metrology demand that systems must be precise and stable to 0.1 % over many years, and linear from 10-14 A to 10-8 A. Thus, laboratories depend on bespoke current measurement systems and often rely on sealed sources to generate reference currents. To maintain and improve present capabilities, metrologists need to overcome two looming challenges: ageing electronics and decreasing availability of sealed sources. Possible solutions using Ultrastable Low-Noise Current Amplifiers (ULCAs), resistive-feedback electrometers, and (quantum) single-electron pumps are reviewed. Broader discussions of IC design and methodology are discussed. ULCAs show promise and resistive-feedback systems which take advantage of standard resistor calibrations offer an alternative.
RESUMEN
The probability of nuclear war is deemed small. A large-scale release of radionuclides into a populated area is considered much more likely. Treatment of radiological casualties is possible even after a detonation that immediately overwhelms surviving local resources. Care would be required at medical centers throughout the country. For those radiological casualties where treatment is most likely to make the difference between survival and death, a window of several days exists in which patients can be identified, dispersed, and therapy initiated. Most deaths due to radiation occur as a result of bone marrow damage and secondary infection. Treatment is based on stimulation of the surviving bone marrow stem cells and protection from infection. With aggressive treatment of immunosuppression, very few deaths should be anticipated at radiation doses of less than 5 Gy. Only those patients who exhibit signs of neurological damage should be considered expectant. All other casualties are candidates for therapy.
