The new vacuum chamber has reached the first stage of completion. The vacuum chamber has been blanked of and where necessary temporary seals have been added to make it vacuum tight. Partly in preparation for an not fusion related, external, experiment (dubbed RMR-TR, more information will follow soon).

Using the current backing pump a lowest pressure of $1\cdot10^{-2}$ mbar and approximate leak rate of $1\cdot10^{-6}$ mbar/s.

A quick experiment was also conducted with the 10kV/10mA Heinzinger high voltage power supply, for more photos and information see RMR-FF5 reactor.

Today we picked up a new (to us) donated vacuum chamber. The stainless steel chamber has eighteen 2.75", five 4.5", one 6" and two 8" CF flanges. These are ideal for future use with multipe ion and electron guns aimed at the polywell at different angles. It also leaves room for all necessary metering equipment, viewports and other feedtroughs. Before the chamber can be put to use a large number of blanks to cap the unused flanges have to be found or made and an adapter for the diffusion pumps has to be milled.

 

After heating the chamber several times to 100 degrees Celcius and once to 150 degrees Celcius for approximately 15 hours total, a best vacuum of $9.75\cdot10^{-7}$ Torr was obtained. This was done using two bake out cords of approximately 350W and carefully wrapping the vacuum chamber in aluminium foil and a thermo blanket. The bake out temperature is limited by our current use of viton and some nitrile o-rings, also the current diffusion oil (DC704EU) will limit the pump at lower pressures. In the future hopefully the o-rings can be replaced, the diffusion oil will be upgraded to DC705 and a much longer bake out will be done.

Today the new vacuum chamber and all parts were assembled. After an initial pumpdown and warm up of the diffusion pump the base pressure seemed to be $6.0\cdot10^{-4}$ mbar according to the new ion gauge. Some initial leak testing showed some problems with certain o-rings.

Update 2012-03-14: After repairing a small crack the ultimate pressure without a bake out is now $5.7\cdot10^{-6}$ mbar.

As the work on the new vacuum chamber continues it is now nearing completion. The inside and outside have been sanded and the flanges have been milled with a precision of more than 0.05mm. When the connection flanges have been made the complete vacuum chamber will be assembled with viton o-rings. When everything operates satisfactory we will attempt to use copper wire seals and start baking out the chamber.

The cluster has been setup and is currently being configured. The current cluster configuration is as follows:

• 16 Nodes: 2.66Ghz dual core, 4gb ram, 250gb HDD
• 2 Gigabit network connections
• Debian Squeeze
• Udpcast imaging of the nodes via PXE boot
• SLURM + OpenMPI + OpenMP for future PIC simulations

Today we received a donation of a nude hot cathode ion gauge (UHV-24) and the necessary controller. This specific ion gauges operates in a range from $1$ mbar to $10^{12}$ mbar and will provide pressure measurements beyond the range of themistor gauges.

After finding a suitable filament the ion gauge will immediately put to use to test the new vacuum chamber. 

The vacuum chamber is slowly nearing completion:

The inside has been extensively sanded to remove roughness left over from casting. A smooth and clean surface will improve vacuum performance by preventing the trapping of dirt and minimizing surface area.