Two other detectors have been used with PISCO: C. Aime and E. Aristidi's ICCD (Intensified Charge Coupled Device) from Nice University, and P. Nisenson's PAPA camera from Harvard Smithsonian Center for Astrophysics (CfA).
The ICCD has a single stage intensifier. It cannot
operate in true photon counting mode and is thus limited to objects brighter
than V 
10. This detector has no significant geometric
distortion nor
non-linearity problems which would affect the photometry measurements. The
exposure time can be set between 64 
sec and 16 msec and the gain of the
micro-channel amplifier can be tuned, thus allowing a wide range of
input luminosities. The output is an analog video signal,
recorded on SVHS video cassettes.
Bispectral image restoration with this detector has been very promising,
and the first attempts lead to the restoration of a triple star
(Aristidi et al., 1997).
The new version of the PAPA camera we have used is not yet fully operational. This former version of this detector was described in Papaliolios and Mertz (1982) and Papaliolios et al., (1985). It features a two-stage electrostatic amplifier, and a fast (P46) phosphor. Amplified photon impacts are analyzed by a set of binary masks which act as an optical computer to instantly digitize the position of photons in the field. The current version has new binary masks setup and a refurbished image intensifier. The development of this new configuration started in 1991 and was jointly made by P. Nisenson, D. Ghezari (CfA) and L. Koechlin (OMP). The first observations in June 1997 have shown that the quantum efficiency was very good, slightly larger than that of the CP40. The maximum photon rate was around 100000, but a small ``hole'' at the center of the autocorrelation function was also noticed. The geometric distortion caused by the image intensifier was large and an overall scale variation during the night imposed quasi permanent scale calibrations.