[time-nuts] Happy New Maser Lock

[Magnus Danielson]

Fellow time-nuts,

On friday I took the delivery of the EFOS10 maser, and this morning it
got temperature of cavity up to support masing, which is really for it
to be sufficiently in tune frequency wise, and then 2 min later the 5
MHz BVA had achieved lock on the signal. The cavity temperature have
stabilized and it outputs a strong and healthy masing signal.

A quick and dirty frequency check that was setup with a OSA 3210 cesium
and then having the 53132A measure 5 MHz output of the EFOS10, also
indicate lock, as it was nicely on 5 MHz sharp, flipping around the mark
as expected. I will setup a more serious measurement setup.

The EFOS10 has a bit of history and I have a lot of documents and log
books to tracks it's history. It's interesting to see how careful it has
been maintained, measured, adjusted etc. and this is valuable
information now as I compare it to older behavior.

As one notice the changes, as it was built in 1990-1991, went through
acceptance tests and later got placed at the VLBI station on Pico Veleta
(2850 m up in south of Spain) as operated by IRAM. After it had failed
its lock on 27 Dec 2018, decision came to decommission it.

Ole helped me to locate it through T4Science, and I bought it from IRAM,
then had T4Science commissioned to pick it up and transport it to
T4Science in Neuchatel. There it was concluded that the palladium valve
had failed, so it was replaced. The palladium valve is responsible for
being the controlled leak of H2 from the H2 tube, and when it fails it
fails in open state, so it emptied the H2 bottle in advance. It also
seems like one of the ion pumps failed, and luckily a spare ion pump was
included as I bought the maser, so that got into use directly.

Hydrogen masers is quite a different beast than cesium beams, it's a
much more serviceable system, but it also takes quite a bit of equipment
to service it. So, if I where to replace an ion-pump, I would need to
have a vacuum pump and a few things to interconnect. Also, to start the
new ion-pump one needs a special power-supply, which luckily was
included in the buy. Did I say that it has an internal and external
vacuum system? The internal is to evacuate from the maser-bulb.

Another thing is that these beasts have many temperature control
systems. A lot of things to monitor, and thanks to Ole I have logging of
all the state every 10s.

Anyway, I ended up having T4Science commissioned to transport it up, and
Sylvère had his son Laurel and his girlfriend Joana drive it up here.
Very good people. We had a nice evening after the quite heavy job of
getting it in the door.

So, I end up being happy with such a good start to the new year. Good
things achieved, many new to work on now that the maser is running.

Many thanks goes out to Ole Petter Rønningen and Sylvère Froidevaux at
T4Science, as well as to Laurel and Joana naturally. Additional people
at T4Science and IRAM to be thanked also!

Happy New Year and Happy New Maser Lock!
Magnus