Simple, high current, antimony ion source.
A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 muA at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6x10(-4) Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8x10(-9) and 1.8x10(11) cm(-3), respectively.
Indium Ion Source
An ion source that utilizes a continuously oxygenated porous tungsten surface to generate indium ions is described. Indium vapor supplied to the back of the tungsten ionizer from a reservoir percolates through to the front surface where the indium is evaporated as ions. An accel‐decel electrode extraction system is used to increase the ion current capability of the source. The ionizer and reservoir are designed to operate at temperatures in excess of 1000°C and at voltages up to 20 keV. The peak ion current attained was 0.57 mA at an ion energy of 10 keV.
Bodies Politic : Disease , Death and Doctors in Britain , 1650-1900
In spite of its intellectual, literary and comic brilliance, this book contains a dark and disturbing, but revealing, message. In some ways, my melancholy reading of Bodies Politic has inevitably been shaped by Roy's recent untimely death. Roy Porter was without doubt the finest social historian of medicine this country, or indeed the world, has produced. Expansive, humorous, intelligent, and incisive, his broad range of historical works has excited and educated several generations of students of history over the past thirty years. His death leaves an unfillable void within the global history of medicine. At the same time, however, this book itself, completed well before his death, is haunted by elements of despair and uncertainty that should make us carefully reconsider not only the purpose and direction of our professional inquiries but also our own mortality.