Vacuum chamber bake out

After several tests with the new turbo pump the system was prepared for bake out to improve the vacuum. With the current heating cables, attached equipment and remaining viton gaskets the maximum bake out temperature is 150 degrees Celcius. The chamber has been wrapped in aluminium foil to minimize heat loss and to improve the heat distribution. An uneven heating profile could crack the viewports.

The heating cables provide a maximum power of 700W which gives a temperature ramp of approximately 1deg/minute.


Vacuum system cleaning and conversion to a turbo pump

Over the past few months the vacuum system has been extensively cleaned and changed from a diffusion pump system to a turbo molecular vacuum pump.

Website redesign

After a period of relative silence the new website is finally live. Because of technical reasons it was decided to migrate the website back-end from Confluence to Drupal. This involved converting the content and theme.

The theme was slightly changed for a lighter look and hereby the new logo is formally introduced.

Below is a screenshot of the old website and a desktop wallpaper with the new logo.

Initial plasma spectrosopy results

Recently a Verity 200Mmc monochromator was acquired to start experiments using plasma spectroscopy in a Farnsworth Fusor. The entrance and exit slits were modified to provide higher resolution and calibration using a HeNe $632.8 nm$ laser gives a FHWM of $\le 0.2 nm$. The monochromator has been integrated in EPICS and Control System Studio for easy interfacing.

The manual control was replaced with a stepper motor to automatically scan a spectral range with a positioning resolution of $0.015 nm$. The graph below provides some initial results from a $H_2$ Farnsworth plasma; grid bias voltage was negative and the plots have been normalized.

Data acquisition and control systems

Because of the large amount of data produced during the experiments it was necessary to design a flexible and reliable logging and control system. This systems logs for example grid voltage, grid current, pressures, temperatures, gas spectrums, light spectrums and more.

The system consists of four main parts:

  • Hardware interface
  • Software interface
  • Data viewing
  • Data logging

RMR-FF5 operational

After two years of development the RMR-FF5 fusor is finally operational. All elements of the fusor are finished and the first neutrons were produced and measured. Several runs were completed to test the different neutron detectors up to a maximum of $35$kV grid voltage. Initially the count rate and $D_2$ flow was a little bit to low and the star mode was somewhat whiteish, increasing the $D_2$ flow a little bit returned it back to a bright purple. Both He3 tubes gave a count rate of approximately 0.5-1 cps (1-2 cpm background) at $\lt25$kV at $300$mm distance from the grid center using the remball shell as moderator. $0.5-1$cps seems a bit on the low side and the best estimates give approximately $20.000$ fusions/s. Most likely the LLD, ULD and noise of the preamplfier, amplifier and counting setup are not yet ideal.

Deuterium production using a PEM cell

To provide deuterium for fusion experiments it is produced from the easily available deuterium oxide ($D_2O$), more commonly known as heavy water. In the past an electrolysis system was used that required a large dryer. To simplify and improve this system it was replaced with a PEM cell (similar to a hydrogen fuel cell) which negates the necessity of a dryer. A glass syringe is used to store a small supply of $D_2$ as a buffer and is connected to a cut off when it is full.


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