Electrical Sample Mounts
A family of electrical mounts allow the user to pre-mount samples on small chips or circuit boards to easily make electrical connections. These have been specially designed to work with other mounts and configurations, with an emphasis on preserving thermal performance.
Standard electrical sample mounting options are detailed below:
|Electrical Sample Mounts|
|Description||circuit board with electrical contact pads and coax connections||circuit board with electrical contact pads and pins||holds standard DIP16 chip carriers||wire bonding pads on narrow circuit board with pitch connector|
|Low Voltage Connections||12 DC||12 DC||16 DC||14 DC|
|High Frequency Connections||2 RF coax||n/a||n/a||n/a|
|Configurations||Standard mount or piezo mount||Standard mount or fixed mounts||Fixed mount or piezo mount||Parallel, normal, or 45° to lateral|
|Best For||coplanar waveguides, microwave excitation, & low signal level experiments||low working distance, high impedance, & compact areas such as castles||use with chip carriers and quick sample changes||use with Magneto-Optic module|
*Electrical sample mounts should have at least 1mm of spacing on either side.
The R2D12 has 12 low frequency DC connectors along with 2 high frequency RF (coax) connectors on a small circuit board. The chip carrier is easily removed from the cryostat sample mount, providing a convenient platform for wire bonding or soldering electrical connections between the user's device and the chip carrier. The 12 wire bonding pads connect via ribbon flex circuits which provide superior thermal anchoring and keep the wiring clean and organized.
The ribbon flex circuit connects the wire bonding pads (left/center) to the exterior base side panel (right).
The 2 RF bonding pads are great for coplanar waveguide studies. The signal remains shielded all the way to the device under study, ensuring a lower loss of signal. An internal copper shielding layer shields the DC lines from the RF coax to prevent signal distortion, enabling both high voltage experiments and sensitive, low signal level experiments.
The R2D12 can be mounted on the standard thermally damped sample mount (left) or on a fixed mount for use on piezo positioners (right).
The sample chip is surrounded by a ground layer for additional electromagnetic shielding. The sample surface sits above the PCB height to allow for low working distance. The grounding scheme can be reconfigured by the user per their experimental requirements, and the number and type of contacts can be customized by Montana Instruments upon request.
The CB12 has 12 connections on a small circuit board with the sample mount directly mounted to the post. It allows for easy exchange of the sample board with wires on the mounting post. The electrical contact pins are at 2mm spacing for a standard connector or can be soldered to individually. The contact pads are at the same temperature as the sample. A radiation shield at the sample temperature may be installed above the sample.
The sample pad ensures a cold sample. Once the sample is mounted and electrically connected, the sample pad may be permanently fastened to the electrical contact board. Multiple assemblies may be used for multiple samples. The sample stands proud on the platform for both top and radial optical access.
The standard sample support accepts many types of sample mounts including the thermally damped sample mount in various adjustable positions. A thermally damped sample mount ensures sample stability of better than 10mK and may be positioned near any of the radial or top optical ports in the Cryostation.
The DIP16 electrical sample mount is designed to hold standard DIP16 chip carriers with the sample mounted in the carrier and wire bonded to the chip contact pins. The pins of the chip slide into a row of sockets which are electrically connected to the feedthroughs. The images below show the components assembled on a fixed mount.
The DIP mount is compatible with the piezo stages, but it may require a taller housing based on the height of the piezo stage selected.
The MO14 circuit board is designed for positioning samples with electrical connections within the magnetic field of the Magneto-Optical system. The circuit board offers 14 pads for wire bonding and a 1mm pitch connector at the bottom to cable the board to the measurement devices outside the cryostat. The board has space for a 3mm wide sample which works well with the pole tip spacing of 12mm for a 0.7 Tesla field. A radiation shield at the sample temperature may be installed above the sample.
The sample pad ensures a cold sample. Once the sample is mounted and electrically connected, the sample pad may be permanently fastened to the electrical contact board. Multiple assemblies may be used for multiple samples. Mounts are available to position the board at angles with respect to the field and optical axes.
Often users want to investigate their samples in the Faraday and Voigt geometries. The user can position their sample parallel or normal to the lateral magnetic field. Alternatively, the assembly may be mounted on a rotary piezo stack with a vertical axis and thus rotated while at cryogenic temperatures.
A narrow option is also available (shown below) which can be mounted at 45 degrees for reflection measurements.