South Pole Diaries 1997/98

   

   

Thursday 4th December 1997 - New author !

From John Storey.....

Hi all,

I will endeavour to uphold the standard JWVS has maintained on action down here at the Pole, but doubt I will attain his level of wit .....

Today was an almost AASTO-less day for me. Michael was beavering away on s/w, with little involvement from me. I spent the day working on Abu related issues.

Firstly, Dave Pernic finished the new flexible cryogenic lines, so we (Mike Masterman and myself) installed those. Then we started pumping on the complete length - around 125 feet. After finding a few finger tight connections, and tightening the requisite amount ("strip it, back it off half a turn"), we found the Alcatel could bring a 125 foot line down to 1x10**-3 Torr in less than 30 minutes - but then just plateaued there for hours without budging a nano-Torr.

After some thought (see below) we decided that it was due to something outgassing - the most likely substance being water, which at 0 deg C has a vapour pressure of around 4 Torr - but at -30 it is down to 9 milliTorr. This evening, after pumping for around 10-12 hours, the pressure was down to 2.8x**-6, which I think is excellent. We have started on the second line, and tomorrow morning we will start the fill/purge sequence with ultra-pure Helium.

(Note: the Cal 2200 temperature controllers we use for controlling the temperature of the environmental enclosures is WAY WAY smarter than the Tektronix scope John was intimidated by - it may even be smarter than the Fluke. It suggested we check difference substances for outgassing qualities ..... and it was right ! Sadly it does not have the Flukes self-effacing manner ....)

Tonight we started to align Abu. This consists of using a laser to determine the center of the geometric axis of the T-tube, and to compare this to where the IR beam is exiting the T-tube. Ideally you would like these to be the same ......

After much fiddling, we finally achieved the desired result. This required the use of a number of ancient units of measure, not used for many years, but which proved ideal for the precision adjustments required in this procedure due to everyones initmate familiarity with such such natural units.

For me, the day was slightly broken up by a much needed shower - 5 days without is enough, or so I'm told by everyone around me ..... JWVS couldn't wait, and deserted the base last night, arriving at MCM at 3 this morning, when they are probably putting the vegys on to boil for tonights dinner ...... and the smell was probably worse.

In addition, we had another 5:00 pm CARA meeting - at which nobody was "cased" (not that anyone has paid their fines yet but .....). The excuses this time were considered adequate, as several members were involved in a practice disaster, to see how the fire crew responded. I think most "victims" have now been found......

The meeting (as was Mondays) was much the poorer for the absence of Finn, alias Dave Barnaby. Rodney made his best effort to fill the shoes of our recently departed colleague, and it is clear he may yet be able to fill Finns role in these meetings ...... though the lack of a personal electronic assistant is clearly a handicap (I suggest using a PC104 system, or possibly a Cal 220 controller).

Fred has removed the tertiary mirror and support tower and we spent some time this evening working out how to mount our new tertiary mirror. It is a fiddly, but quite tractable problem.

OK, well, I'm sure I did something else today, but can't remember what, and as it is now midnight, I shall retire. Oh yes, I have a JWVS replacement - he is a visiting Japanese scientist examining logistics, base support etc. He is very interested in the wind generator here, but a little perplexed as to why that particular style was chosen. He sleeps more soundly, and does not mutter abuse at the Tektronix, Fluke, and even the Weller soldering iron in his sleep, unlike my previous room-mate, who was convinced most electrically operated items were more intelligent than him, and was last seen backing away from a kitchen garbage disposal and up the ramp towards the Hercules with a fearful and suspicious look in his eye.

Cheers

Ant

 

 

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