NIKHEF
 Rasnik
demokit

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

(copyright)

You may want to go to the RASNIK for ATLAS pages.
The links below only point to information about the obsolete demo-kit.


About the sensor

The projected pattern of the mask is converted to a standard video signal by the sensor. this can be a CCD (Charge Coupled Device) or a CMOS sensor. In the demokit this is a B&W observation camera without a lens. The video signal from CCD sensor is digitized by means of a framegrabber in a PC AT. The generated file contains 768*512 gray values (8 bit). This file is analized by means of a reconstruction program, running on a workstation. You can read more about things that affect the accuracy of the measurement. 

About the software (ICARAS)

The ICARAS software includes this reconstruction software, which is improved constantly. ICARAS also takes care of switching the lightsources on and off by controlling the Ras_Mux and grabbing images.
Read more about the ICARAS software

About the demokit

The demokit is a set of components plus software to demonstrate to the user the capabilities of the system. See the details of the demokit, pictures and software. Or have a look at the mechanical drawings. Please keep in mind the demokit is not compatible with the ATLAS system. Furthermore it is no longer available from NIKHEF. For questions about this contact Harry vd. Graaf.

About multiple systems (RAS_MUX)

To set up multiple alignment systems in experimental set-ups, a module has been developed. This module connects one of the sensors to the framegrabber and switches the LEDs on and off. It is controlled from the parallel port of a PC for example. In the ICARAS software this control is fully integrated. For the demokit you can read more about Ras_Mux.

CCD_Rasnik

For a long period the name of the system used be CCD_Rasnik. But the principle does not depend on the process with which the sensor is created. Over ten years ago we used a four quadrant diode to monitor the alignment in the L3 muon spectrometer, using the name RASNIK. So in march 1999 we decided to return to the old, more general name RASNIK.


You can go to

You can mail  suggestions for this page to: Henk Groenstege.
updated: march 1999