Fasti Rationale

Fasti is an innovative design for infrared detector control.

The present-day commercial electronics for reading bi-dimensional near-infrared array detectors often lack useful feature as quick sub-array fast acquisition, or is based on old components, or cannot cope with newer devices, as the 2048x2048, multi--output Rockwell Hawaii-2. All these devices share the read-out scheme, the DRO (Direct Read Out) technique. That technique can be used also to achieve the combination of low read out noise and high frame rate necessary for Adaptive Optics applications.

Some recent technological advances enable us to propose a controller for these DRO array detectors (for example near IR HgCdTe detectors) which is designed to overcome all cited difficulties. Named Fasti, it is meant to be a "light" electronic system, which is modular, flexible, extendible, and avoids obsolescence as much as possible. The design does not constrain the downhill controlling computer: Fasti is seen as a peripheral through a network connection.

The basic ideas of the proposed design are:

• to divide the system in several "modules" with clear boundaries
• to use, as far as possible, commercial parts at board level
• to use largely accepted standards as boundaries, as a PCI bus, a parallel interface or a serial, and to use few of them
• to design the few custom parts as concepts, not around a particular electronic device, so that they could be implemented by components from any manufacturer, or by devices developed in the future
• to be as flexible as possible on waveform generation

Fasti design fits all these requirements, and we are now in the phase of building a prototype of the critical subsystems. The prototype of the full system will be tested with the TIRGO focal plane instruments (Arnica and Longsp, both using NICMOS-3 256x256 array), and Nics (the TNG 1024x1024 array camera spectrometer). Implementation for Adaptive Optics applications will also be investigated.