The Linkam motor driven stage is ideal for use with all transmitted light microscopes and can be used in confocal, laser raman and FTIR applications. The silver block is of a similar construction to the THMS 600 but has its cooling pipes at 180° to each other. This reduces the flow of liquid nitrogen needed to cool the block and minimizes any up and down movement of the block as it heats or cools.
A very low linear expansion coefficient sample carrier made from invar, securely holds the quartz sample disc in position on the block so that any movement in the block has no effect on the sample position. A 15mm X, Y travel allows the sample carrier to move the sample over the 1.3mm center window, enabling a large field of view, but maintaining the temperature accuracy due to the extremely low temperature gradient across the block.
The X, Y position is controlled by two precision motors, with direct drive to a set of linear bearings, resulting in no vibration even at the fastest speeds. A micro-stepping motor controller allows a resolution of 0.05mm and a positional repeatability of <3µm. Windows based software integrates with the LINK software and the RTVMS to allow control of the whole system to give on screen video and capture, measurement, sample movement and temperature control.
Using the on-screen joystick the sample can be moved around in either discreet steps, continuous motion or in an X, Y ‘snake’ scan. The speed may be changed at any time and up to 150 positions can be stored and saved for positional recall.
Other features of the software include a point-to-point function whereby two positions are specified in the video window and the motors will move the sample from one position to the other. A centering function can also be used to move the position specified in the video window to the center of the field of view.
The motor controller and software can also drive an optional Z axis or focus motor which can be fitted to the fine focus knob of most of the newer microscopes. The speed can vary from 1 to 500mm/s with 150 focus points stored together with the X, Y positions. The focus can be moved in either step or continuous motion. The resolution of the Z axis is dependent on the model of the microscope as they all have differing distances per turn of the focus knob. As an example, a 100mm/turn microscope will allow a resolution of 0.005mm.
The MDS 600 system is designed primarily to be run from the PC. However, the X, Y motors can be hand operated thus making the system even more flexible and versatile.
For seeding and freeze drying a cold spot has been provided on one of the cooling pipes allowing nucleated freezing to be initiated. High speed quench cooling is also available by moving the sample from a warm post onto a pre-cooled block, at high speeds. Because the speed can be varied from 5 to 5000mm/s it allows ice fronts to be studied as they propagate across the surface.
The motor drive unit simply connects to the computer via a single RS 232 serial port which is shared with the programmer.