[time-nuts] Cheap Rubidium (heatpipe cooling for)

J. Forster jfor at quik.com
Sat Dec 26 03:56:25 UTC 2009


I bought it at a physical store last summer. It was on a shelf for $20
with other picnic things. Chinese, of course. It takes a 6-pack of coke
and if it's cold outside (50F) cools enough to freeze after a day of
operation.

Outside it's anout 8" x 14" x 10" high (from memory). Black plastic. It
runs of 12 VDC at about 3 A. It includes a power supply (noisy switcher)
for line operation. There is a HEAT/OFF/COOL switch.

I looked a few weeks ago and Target and Best Buy both had similar units (a
bit bigger) for about $100.

Ask the Walgreens store manager.

FWIW,
-John

============


> Can you be a little more specific about the cooler ? Walgreens
> search function is rather laborious and clumsy.
>
> Tnx, Dick, W1KSZ
>
>
> -----Original Message-----
>>From: "J. Forster" <jfor at quik.com>
>>Sent: Dec 24, 2009 6:58 PM
>>To: Discussion of precise time and frequency measurement
>> <time-nuts at febo.com>
>>Subject: Re: [time-nuts] Cheap Rubidium (heatpipe cooling for)
>>
>>That's why I've been suggesting active control with TE devices.
>>
>>You can buy a small TE cooler at Walgreens for about $20. It's big enough
>>for a 6-pack of Coke cans and already comes in an insulated box. Add a
>>simple temperature control in series w/ the DC supply and you should be
>>well on the way.
>>
>>-John
>>
>>=================
>>
>>
>>> Hi
>>>
>>> The original intent was to simply take an existing "cheap" rubidium and
>>> do
>>> simple things to it. Tearing it into pieces and redesigning parts of it
>>> was not anything I originally contemplated. The tight integration of
>>> the
>>> physics package to the electronics would make this a fairly involved
>>> process.
>>>
>>> Bob
>>>
>>>
>>> On Dec 24, 2009, at 5:42 PM, Magnus Danielson wrote:
>>>
>>>> Hal Murray wrote:
>>>>>> A heat pipe might work if the fluid had a sufficiently low boiling
>>>>>> point. The rubidium isn't terribly tolerant of high temperatures,
>>>>>> and
>>>>>> I'm going to pick up some heat rise as I put it inside some baffles
>>>>>> /
>>>>>> shields. You need to find something that fits a fairly narrow
>>>>>> window.
>>>>> This is all backwards.
>>>>> The main reason the typical Rubidium box needs a serious heat sink is
>>>>> that there is an active heater inside it heating up the lamp to get
>>>>> it
>>>>> up to operating temperature.  That part of the system better be
>>>>> "tolerant" of high (enough) temperature.
>>>>
>>>> ... or a less heat-producing alternative could be used. The
>>>> Rubidium-lamp produces two wavelengths of which one is filtered by a
>>>> Rubidium-filter which leaves the final pumping wavelength. This is
>>>> what
>>>> a laser diode could supply instead.
>>>>
>>>>> Maybe things would be a lot better/simpler if the heating/cooling we
>>>>> have been discussing were split into two sections.  One for the lamp
>>>>> assembly, and a second for the electronics.
>>>>
>>>> Most of the discussion has been on thermal isolation of the entier
>>>> units. Not what needs generates temperature and what requires
>>>> temperature stability etc.
>>>>
>>>>> Anybody know what the thermal coefficient of the lamp is relative to
>>>>> the electronics?
>>>>
>>>> I am not sure I know what you mean by this...
>>>>
>>>> Cheers,
>>>> Magnus
>>>>
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>>>
>>>
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>>
>>
>>
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>





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