Rasnik is a wide range, high precision
alignment monitoring system, developed at NIKHEF.
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
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
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
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
updated: march 1999