Performance of position sensitive scintillator detectors when readout with a low noise photodevice
The technique of position sensitive scintillating bar detectors used as the building blocks of position sensitive planes offers the remarkable advantage of greatly reducing the number of readout electronic chains. A position sensitive bar is usually readout by two photo-detectors and, combining the two signals, energy and position of an interacting particle or gamma-ray can be evaluated. In this kind of detector the performances can suffer from the double readout that introduces the noise and uncertainty of two readout systems. The use of Silicon Drift Chamber as a photo-detector opens new perspectives in the design of scintillating bar detectors. In this case the high quantum efficiency of Si for light detection and the very low noise of the device practically cancel the disadvantages of a double readout system. In this work the results achieved stimulating with gamma rays of different energies scintillating bars with square cross section of 3 mm and various length from 15 cm to few cm, with double side Silicon Drift Chamber readout are presented and discussed. For these test an old scintillating material as CsI(Tl) has been chosen manly for its easy availability in different shapes and the good matching of the wavelength of its scintillation light with Si. The use of different materials is also discussed.
Detectors for high-resolution gamma-ray imaging based on a single CsI(Tl) scintillator coupled to an array of silicon drift detectors
Silicon drift detectors (SDDs) coupled to scintillators have been recently employed successfully in gamma-ray detection. The low value of output capacitance of an SDD allows to reach a lower electronics noise with respect to a conventional silicon photodiode. Detectors based on array of SDDs are of particular interest for gamma-ray imaging. A first prototype conceived for high-resolution imaging is based on a monolithic array of small SDDs (5 mm/sup 2/ each unit) with on-chip junction field-effect transistor (JFET). The first results obtained with a seven-elements array are here reported. For the realization of gamma detectors of larger active areas based on assembled units; SDDs of 30 mm/sup 2/ of area with external JFET have been produced. We present the experimental results obtained in the characterization of a single CsI(Tl)-SDD unit.
List of the described Coleoptera ofTasmania.
The Coleoptera of Tasmania have never been considered as 
a whole since the time of Erichson, and no list or 
catalogue of the species has ever been compiled. About 
10,000 species have now been recorded from Australia and 
Tasmania, of which scarcely 400 have been described from 
Tasmania. A very imperfect knowledge of what species 
are confined to the island exists, as species supposed only 
to occur there, are constantly being found in Victoria and 
New South Wales, and even sometimes in Western Australia 
and Queensland; on the other hand, Tasmanian 
collectors frequently obtain mainland species which have 
never been recorded from Tasmania. 
I have considered it advisable, therefore, to prepare a 
list of the species hitherto recorded from Tasmania, adding 
to the list such species as I have seen in Tasmanian collections, 
or have myself taken in Tasmania. In this list, 
the genera and families are placed as far as possible in the 
order in which they appear in Masters' "Catalogue of the 
Described Coleoptera of Australia;" the species are placed 
alphabetically. All known synonyms have been omitted.