HP 5071A Electron Multiplier of Cesium Beam Tube
Hi all,
I got an HP 5071A,but it did not work.I think the Electron Multiplier decay problem. I want to change Electron Multiplier of Cesium Beam Tube .
where to buy the Electron Multiplier and how to replace it? Thanks.
weijiazhen
Is this even POSSIBLE without a very advanced tube manufacturing facility?
-John
==================
Hi all,
I got an HP 5071A,but it did not work.I think the Electron Multiplier
decay problem. I want to change Electron Multiplier of Cesium Beam Tube .
where to buy the Electron Multiplier and how to replace it? Thanks.
weijiazhen
time-nuts mailing list -- time-nuts@febo.com
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weijiazhen@sina.com wrote:
Hi all,
I got an HP 5071A,but it did not work.I think the Electron Multiplier
decay problem. I want to change Electron Multiplier of Cesium Beam Tube .
where to buy the Electron Multiplier and how to replace it? Thanks.
weijiazhen
If you are not a CBT production line:
"forget about it"
On the other hand, if you are a CBT production line:
also "forget about it"
Back when HP/Agilent made the tubes, they welded them shut, baked
them out, pulled a vacuum on them, and sealed them, but did NOT
break the glass ampule that held the cesium. They then did various
tests on the CBT. A fair percentage of them did not pass. In
that case, they were sent to the machine shop and placed in a lathe.
Any expert machinist cut off the weld, which went around the tube,
without damaging the structure beyond repair. Of course, this
caused the high vacuum inside the CBT to escape :-) The CBT's
were then sent back to the CBT line for rework, etc. It is important
to understand that this was done with the cesium safely contained
in the ampule. If a CBT passed the initial tests, a firing pin was
used to break the ampule, using a magnet to activate it, IIRC.
According to the CBT people, it was not practical to rework CBT's
that had the cesium released, let alone to rework used CBT's.
Used CBT's are even worse because everything is "cesiated".
Rick Karlquist N6RK
Cesium is pretty reactive and could likely be stripped off chemically and
the CBT tube cleaned.
People can make simple triodes at home (with a lot of stuff). There were
guys 'rebuilding' CRTs in the late 50s at home. However a CBT or other
things with electron multipliers are FAR from a simple triode. You not
only need exquisite vacuum technique, but also to be able to activate the
electron multiplier. These are non-trivial things to do, even for large,
expert companies. I was told by a guy at Varian that they typically did
three tube starts for every one delivered on image intensifiers, which
have MCP multipliers.
This is part of the reason I've never bought a used Cs standard. Most
likely it's a $$$ doorstop, and always will be.
FWIW,
-John
=============
weijiazhen@sina.com wrote:
Hi all,
I got an HP 5071A,but it did not work.I think the Electron Multiplier
decay problem. I want to change Electron Multiplier of Cesium Beam Tube
.
where to buy the Electron Multiplier and how to replace it? Thanks.
weijiazhen
If you are not a CBT production line:
"forget about it"
On the other hand, if you are a CBT production line:
also "forget about it"
Back when HP/Agilent made the tubes, they welded them shut, baked
them out, pulled a vacuum on them, and sealed them, but did NOT
break the glass ampule that held the cesium. They then did various
tests on the CBT. A fair percentage of them did not pass. In
that case, they were sent to the machine shop and placed in a lathe.
Any expert machinist cut off the weld, which went around the tube,
without damaging the structure beyond repair. Of course, this
caused the high vacuum inside the CBT to escape :-) The CBT's
were then sent back to the CBT line for rework, etc. It is important
to understand that this was done with the cesium safely contained
in the ampule. If a CBT passed the initial tests, a firing pin was
used to break the ampule, using a magnet to activate it, IIRC.
According to the CBT people, it was not practical to rework CBT's
that had the cesium released, let alone to rework used CBT's.
Used CBT's are even worse because everything is "cesiated".
Rick Karlquist N6RK
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On 9/6/09 10:04 AM, "J. Forster" jfor@quik.com wrote:
Cesium is pretty reactive and could likely be stripped off chemically and
the CBT tube cleaned.
People can make simple triodes at home (with a lot of stuff). There were
guys 'rebuilding' CRTs in the late 50s at home. However a CBT or other
things with electron multipliers are FAR from a simple triode. You not
only need exquisite vacuum technique, but also to be able to activate the
electron multiplier. These are non-trivial things to do, even for large,
expert companies. I was told by a guy at Varian that they typically did
three tube starts for every one delivered on image intensifiers, which
have MCP multipliers.
This is true on a lot of high performance vacuum/ion devices, like
Travelling Wave Tubes. Start 10 to get 3 at the end, especially for a low
volume design; a production line doing a run of dozens might get better
yield, but there's a lot of art in the process. You can do some rework at
various points to get parts to start another, similar to what Rick described
with cutting the weld apart.
J. Forster wrote:
Cesium is pretty reactive and could likely be stripped off chemically and
the CBT tube cleaned.
The HP/Agilent CBT experts claimed they didn't know how to do this, at least
for any economically viable cost. They also said they have been
asked this question approximately 2 gazillion times.
Rick Karlquist N6RK
I wonder why? Cs oxide and many other Cs salts are very water soluable. It
might be that in the process of stripping the tube insides, some porous
ceramic material might become contaminated with a Cs salt and loose its
insulating properties.
I've seen a similar thing w/ the HP Zeeman Split HeNe lasers used for
precision metrology in Laser Interferometers. Those tubes very slowly leak
He and loose output power. There are rebuild companies, but I've studied
ways to rejuvenate them w/o breaking the tube seal.
Best,
-John
===========
J. Forster wrote:
Cesium is pretty reactive and could likely be stripped off chemically
and
the CBT tube cleaned.
The HP/Agilent CBT experts claimed they didn't know how to do this, at
least
for any economically viable cost. They also said they have been
asked this question approximately 2 gazillion times.
Rick Karlquist N6RK
In message a1816d2c8e3e1a65e67636c1a08cf08a.squirrel@webmail.sonic.net, "Rick
Karlquist" writes:
J. Forster wrote:
Cesium is pretty reactive and could likely be stripped off chemically and
the CBT tube cleaned.
The HP/Agilent CBT experts claimed they didn't know how to do this, at least
for any economically viable cost. They also said they have been
asked this question approximately 2 gazillion times.
The problem is not inactivating the cesium, that happens when pretty much
any gas enteres the tube. The problem is getting the resulting chemical
compounds cleaned out. Cs salts are not very soluble in pretty much
anything.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
In message 1387.12.6.201.168.1252258751.squirrel@popacctsnew.quik.com, "J. Fo
rster" writes:
I wonder why? Cs oxide and many other Cs salts are very water soluable.
Water doesn't work for a number of reasons, but mostly because Cs salts
in water is very corrosive.
You would have to find some non-polar solvent, and none of those will
dissolve Cs salts.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
REALLY??
Both Cesium Chloride and Nitride are soluable >50 g/100 ml of water.
When Cs is exposed to air, it forms Cs Oxide, very quickly. That reacts
with water to make Cs Hydroxide. The Hydroxide would react w/ Hydrochloric
or Nitric acid to form the very soluable salts listed above.
-John
==========
[snip]
The problem is not inactivating the cesium, that happens when pretty much
any gas enteres the tube. The problem is getting the resulting chemical
compounds cleaned out. Cs salts are not very soluble in pretty much
anything.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by
incompetence.
In message 1399.12.6.201.168.1252259264.squirrel@popacctsnew.quik.com, "J. Fo
rster" writes:
REALLY??
Both Cesium Chloride and Nitride are soluable >50 g/100 ml of water.
Sorry for not being explicit: Water is out of the question, dissolved
Cesium in water is very bad for pretty much any other metal.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Cs reacts with oxigen and moisture in the air. In
an inert atmosphere of nitrogen or argon,
the tube can be safely opened. Lab digestor can both hold the atmosphere,
and also lead the Cs vapor out . Warming the tube
to 200°C will cause the Cs to sublime in few hours.
At 09:45 6.9.2009, you wrote:
Hi all,
I got an HP 5071A,but it did not work.I think
the Electron Multiplier decay problem. I want to
change Electron Multiplier of Cesium Beam Tube .
where to buy the Electron Multiplier and how to replace it? Thanks.
weijiazhen
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
__________ Information from ESET NOD32
Antivirus, version of virus signature database 4399 (20090905) __________
The message was checked by ESET NOD32 Antivirus.
Of course, you'd hear the same thing if you asked the modern-day HP if they
could refurbish an inkjet cartridge. :) Not the same thing, and not the
same company, I know... but still, HP had no incentive to try very hard to
develop a reconditioning process, at least before Datum started selling
replacement tubes.
One problem is, the job would have to be done under vacuum at every step, or
at least in an inert-gas atmosphere. That means either some kind of glove
box or robotics. If any oxygen were to enter the tube, the cesium that's
deposited everywhere would oxidize immediately and irreversibly ruin any
surface it's on.
My guess is that anyone capable of reconditioning a Cs tube at home would
also be capable of building one from scratch. Easier to earn the $30K for a
new one at McDonald's, would be my guess.
-- john, KE5FX
J. Forster wrote:
Cesium is pretty reactive and could likely be stripped off
chemically and
the CBT tube cleaned.
The HP/Agilent CBT experts claimed they didn't know how to do
this, at least
for any economically viable cost. They also said they have been
asked this question approximately 2 gazillion times.
Rick Karlquist N6RK
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Out of curiosity, what do the Datum tubes sell for? Are they any good?
-John
==============
Of course, you'd hear the same thing if you asked the modern-day HP if
they
could refurbish an inkjet cartridge. :) Not the same thing, and not the
same company, I know... but still, HP had no incentive to try very hard to
develop a reconditioning process, at least before Datum started selling
replacement tubes.
One problem is, the job would have to be done under vacuum at every step,
or
at least in an inert-gas atmosphere. That means either some kind of glove
box or robotics. If any oxygen were to enter the tube, the cesium that's
deposited everywhere would oxidize immediately and irreversibly ruin any
surface it's on.
My guess is that anyone capable of reconditioning a Cs tube at home would
also be capable of building one from scratch. Easier to earn the $30K for
a
new one at McDonald's, would be my guess.
-- john, KE5FX
J. Forster wrote:
Cesium is pretty reactive and could likely be stripped off
chemically and
the CBT tube cleaned.
The HP/Agilent CBT experts claimed they didn't know how to do
this, at least
for any economically viable cost. They also said they have been
asked this question approximately 2 gazillion times.
Rick Karlquist N6RK
John Miles wrote:
Of course, you'd hear the same thing if you asked the modern-day HP if
they
could refurbish an inkjet cartridge. :) Not the same thing, and not the
same company, I know... but still, HP had no incentive to try very hard to
develop a reconditioning process, at least before Datum started selling
replacement tubes.
FWIW:
Wait a minute. Datum owns Symmetricom which bought HP/Agilent's
CBT production line and admits that their tubes were never as
good as HP/Agilent's tubes. The 5071, as opposed to the 5061, has
a ROM with a password in the CBT so that only OEM tubes will work.
The password consists of a poem written by Len Cutler. The poem is
copyrighted so that it would be illegal for a competitor to simply
reproduce it, according to Len.
Rick Karlquist N6RK
Out of curiosity, what do the Datum tubes sell for? Are they any good?
I've never seen a price list anywhere, just the brochure (
http://www.gigatest.net/datum/cesium_tubes.pdf ). No doubt the replacement
A9 and A11 modules increase the package price substantially, if they still
sell them at all.
Wait a minute. Datum owns Symmetricom which bought HP/Agilent's
CBT production line and admits that their tubes were never as
good as HP/Agilent's tubes. The 5071, as opposed to the 5061, has
a ROM with a password in the CBT so that only OEM tubes will work.
The password consists of a poem written by Len Cutler. The poem is
copyrighted so that it would be illegal for a competitor to simply
reproduce it, according to Len.
Heh, that's awesome! But with inkjet case rulings coming down on the side
of the aftermarket vendors (e.g.
http://www.techdirt.com/article.php?sid=20041026/103208 ) I suspect the
judge would chuckle, give the plaintiff an E for effort, and then find for
the defendant. Of course the 5071A predates the DMCA by a few years, as it
did the Symmetricom purchase, so who knows what would have happened in
reality.
My 'new' eBay-special 5061A has one of the Datum tubes and a 10811-60109
upgrade. I don't know how old the tube is, or how it performed relative to
HP's specs when new, but the short-term noise on the 5 MHz output is within
specs despite the tube's measured (Vp-Vv)/Vb value being only about 0.8
instead of >1 as called for in the 5061A manual.
Peak beam current with this tube is about 25 nA (-980mv pk into 40 Mohms),
compared to the 80-200 nA typical range that the manual calls for, and the
Cs resonance valley isn't much higher than the noise floor observed with no
RF applied (-550 mv versus -520 mv). But the output phase noise, at least,
is well within specs (-88 dBc/Hz at 1 Hz in short time constant mode,
spec=-82 dBc/Hz, and -105 in LTC mode, which is actually better than the -96
dBc/Hz spec for the option-004 tube.)
One thing I find confusing is how HP's published ADEV and PN specs didn't
change between the 5061A->5061B generations. I'd think the short-term
stability would have gotten better when they went to the 10811-60109 for the
'B' model -- hence my better-than-expected PN reading at 1 Hz -- but the
5061B manual still has the same spec charts in it. Obviously most were much
better than spec, but the numbers are so conservative that it's hard to say
how well a particular unit is really performing unless you have a whole
warehouse full of them for comparison.
-- john, KE5FX
yet another reason not to buy a CS clock. What kind of self-destructive bs
is this?
Don
----- Original Message -----
From: "Rick Karlquist" richard@karlquist.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, September 06, 2009 9:54 PM
Subject: Re: [time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube
John Miles wrote:
Of course, you'd hear the same thing if you asked the modern-day HP if
they
could refurbish an inkjet cartridge. :) Not the same thing, and not the
same company, I know... but still, HP had no incentive to try very hard
to
develop a reconditioning process, at least before Datum started selling
replacement tubes.
FWIW:
Wait a minute. Datum owns Symmetricom which bought HP/Agilent's
CBT production line and admits that their tubes were never as
good as HP/Agilent's tubes. The 5071, as opposed to the 5061, has
a ROM with a password in the CBT so that only OEM tubes will work.
The password consists of a poem written by Len Cutler. The poem is
copyrighted so that it would be illegal for a competitor to simply
reproduce it, according to Len.
Rick Karlquist N6RK
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
darn. I should have made clear I meant on the part of Hp/Agilent!!!
No flames please.
Don
----- Original Message -----
From: "Don Latham" djl@montana.com
To: richard@karlquist.com; "Discussion of precise time and frequency
measurement" time-nuts@febo.com
Sent: Sunday, September 06, 2009 11:58 PM
Subject: Re: [time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube
yet another reason not to buy a CS clock. What kind of self-destructive bs
is this?
Don
----- Original Message -----
From: "Rick Karlquist" richard@karlquist.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, September 06, 2009 9:54 PM
Subject: Re: [time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube
John Miles wrote:
Of course, you'd hear the same thing if you asked the modern-day HP if
they
could refurbish an inkjet cartridge. :) Not the same thing, and not the
same company, I know... but still, HP had no incentive to try very hard
to
develop a reconditioning process, at least before Datum started selling
replacement tubes.
FWIW:
Wait a minute. Datum owns Symmetricom which bought HP/Agilent's
CBT production line and admits that their tubes were never as
good as HP/Agilent's tubes. The 5071, as opposed to the 5061, has
a ROM with a password in the CBT so that only OEM tubes will work.
The password consists of a poem written by Len Cutler. The poem is
copyrighted so that it would be illegal for a competitor to simply
reproduce it, according to Len.
Rick Karlquist N6RK
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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and follow the instructions there.
Don Latham wrote:
yet another reason not to buy a CS clock. What kind of self-destructive
bs is this?
The expensive kind.
I recall a discussion about refilling cesium in tubes from another
direction. I was suppriced that they did not understand how cesium
contaminates the tube, how spectrometer and vacuum "pump" is
contaminated etc. They where only discussing the addition of more
cesium. Even my very rudimentary knowledge outweigth them, that suprised me.
Pumping would reduce cesium spills at first magnet, which should be a
significant improvement in lifetime. As the oven temperature is lowered
to reduce stream of cesium, a lower average speed would be achieved,
thus prodicing a longer interaction time which would improve
performance. Alternatively better short-term stability could be achieved
with the improved signal-to-noise.
Cheers,
Magnus
[...]
Peak beam current with this tube is about 25 nA (-980mv pk into 40
Mohms), compared to the 80-200 nA typical range that the manual
calls for, and the Cs resonance valley isn't much higher than the
noise floor observed with no RF applied (-550 mv versus -520 mv).
But the output phase noise, at least, is well within specs (-88
dBc/Hz at 1 Hz in short time constant mode, spec=-82 dBc/Hz, and
105 in LTC mode, which is actually better than the -96 dBc/Hz spec
for the option-004 tube.)
[...]
john, KE5FX
John, out of curiosity, are you using homebrew or commercial to
measure the phase noise ?
If it's homebrew, is there any other information available?
Thanks,
Mike