This blog is to keep up-to-date info on the status of the UMass experiment. The status of current projects should be updated every few days. Information on broken or malfunctioning equipment should be kept here as well. Any parts that need to be orderred should be listed as well.
Where we're at:
Sample cell: Thermocoax still needs to be installed. Questions regarding this: 1) Do we want to expose a long or short section of the thermocoax? 2) How do we insulate the exposed section?, 3) Do we need to order some fine capillary? We also need to work on the guts of the sample cell, i.e. circuit board, pin connections, etc.
Coax cable for fridge: The first priority is to install the superconducting coax. We need to decide on the length. It needs to be long enough so that the SMA connector can be crimped on while in place in the fridge, but we don't want it to go too far up into the 1.5K space. The cable needs to be cut to the precise specifications for crimping the connectors on it. Yiming is going to contact Chao to find out these specifications. The cable needs to be thermally cycled to LN2 several times to release any stresses. The cable also needs a clamp at the 1.5K stage to prevent it from moving after installation. Max has nearly perfected a technique of injecting Apiezon N grease into the displacer around the cable. We should do a few more trial runs to be sure it works reliably. We will then need to install the BeCu cable. We decided to make the length such if the top reaches the top flange of the probe, the bottom end of the cable will be near the top of the 1.5K space. It can then be pushed down to mate with the Nb coax, with attenuators, adapters and/or cold amplifiers in between. The BeCu cable will need to be thermally anchored at this stage using a Cu wire soldered near the attenuator.
Wiring: We have Cinch connectors now. We still need mounting hardware for the Cinch connectors. The details of how to install the thermocoax into the fridge still have to be worked out.
Sample: Yiming is still working on a design for the sample. The wire bonder in Yngvesson's lab is inaccessible while the lab is cleaned. Yiming will talk to the students there to see when it might become available again.