II. Description of The PRIMA facility


I. Introduction
A. The goals of PRIMA
B. Interferometry Tutorial
C. Atmospheric and physical Constraints

II. Description
A. The STS
B. The PRIMET
C. The FSU
D. The DDL
E. PRIMA Software

III. Applications

IV. The Team

V. The Partners

VI. References, links

Description of the facility:

A. The Star Separator

B. The Laser Metrology System

C. The Fringe Sensor Unit

D. The Differential Delay Lines

E. PRIMA Software

The PRIMA Facility main goals are the scientific objectives explained in the first part, to realize it, PRIMA will use different tools, or subsystems: a star separator (STS) per telescope, a system of laser metrology (PRIMET), two fringe sensor unit (FSU), and 4 differential delay lines (DDL), coordinated by the PRIMA software, those the relative disposition on the whole VLTI is given by the following simplified principle scheme (cf fig.1).

General principle scheme of the PRIMA facility

Fig. 1: General principle scheme of the PRIMA facility

In order to follow the work of the different subsystems of PRIMA, we will in each part rely the subsystem to the PRIMA facility and include it in the following general principle scheme. Each telescope will send the beam he observes into a STS (in fact a large field of view beam of 2' diameter). The STS must allow the calibration on a bright star and picking up two stars. The parallel beams coming from the STS will be sent to the FSU, in charge of tracking the fringes via the main delay lines, the differential delay lines and the VLTI infrastructure. A metrology system is in charge of determining the OPD added by the differential delay lines to get the fringes on the FSU B (bright star) and on the instrument (faint star) simultaneously.