Singly or doubly ionized nitrogen beams, including a small part of oxygen i
on beams, were extracted from a cryogenic diode with N2O ice on the anode s
urface. The nominal diode voltage was 100-360 kV, and the peak ion current
was 300 A. With a one-dimensional arrayed pinhole camera with 5 pinholes, v
ery small divergence angle at the beam source was measured. Although, we us
ed a very rough apparatus (not being as sophisticated as the modern version
), the absolute value (measured) of the divergence angle was 5-6 mrad. This
value was small enough for us to recommend this beam as one of the candida
tes for the future ICF or IFE driver. With the same apparatus, we observed
a rather large angle of 25-60 mrad for the proton beam in our former experi
ment. These results indicated that this kind of medium-mass ion beam must b
e investigated in more detail to make clear the potential of the beam. We a
lso developed a Thomson ion spectometer with a CCD detector, which could be
applicable to the above ion beams. The energy spectrum of a proton beam wa
s measured as the early stage preparation of the spectrometer development.
(C) 2001 Elsevier Science B.V. All rights reserved.