Rasnik sensor

Rasnik is a wide range, high precision alignment monitoring system, developed at NIKHEF.

The sensor is based on the VV5430 CMOS sensor from Vision (VVL, VLSI Vision Limited - A company of the ST Microelectronics group). A copy of VVL's documentation of the VV5430 chip is put here for your convenience.     The number of pixels: 384 times 287. Video standard: CCIR. The gamma correction is switched off. Auto gain and auto exposure are switched on. Pixel size: 12 * 12 µm. Array size 4.66 mm * 3.54 mm.

It connects to the RasMux via a single standard FTP cable, the same type that is used in computer networks. This cable contains four wire pairs and carries the following signals:

• Power: A single power supply is required of 9 to 12 V. A card draws less than 100 mA.
• Video: A semi differential video signal is transmitted by the board upon power up.
• Pixel clock: An LVDS (low voltage differential signalling) clock validates the sampling of the pixels transmitted. It runs continiously to simplify the interface to the frame grabber, currently in use at various institutes.
• I²C bus: Using two lines, a bi-directional bus is created. The current settings of the sensor can be read and its settings can be changed.

Tradionally the disadvantage CMOS sensors, compared to CCD sensors, is the lower sensitivity and fixed pattern noise. In modern types this has improved and the properties turned out to be acceptable in our set ups. The advantages compared with a CCD type are:

• single supply and low power consumption
• pixel clock available
• sensor settings can be retrieved and are remote controllable

What 5800 RasCams look like or the test set up .

You can go to

• the RASNIK for ATLAS main page.
• the NIKHEF electronics for ATLAS overview page.
• the NIKHEF home page.