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How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:01 PM

I have a Keithley model 26220 (series 26000) pico ammeter. My other unit- a Keithley model 614 became unreliable, & I bought the series 26000 from a surplus equipment dealer advertising on ebay. The 26000 series unit is a "logarithmic pico ammeter" that does NOT have its own on-board floating power supply as many such instruments do, but it has "hi & lo calibration/recover capabilities/functionalities" that I do NOT know how to use.

I don't have an operations manual nor do I know how to use the calibration/operation controls on the unit. I have searched for a manual & Tektronix, who bought Keithley, says they are unable to provide same nor be helpful.

So, can anyone help me, please, with documentation or instructions ???

Dr. Paul Melnikov University of Illinois at Chicago, Dept. of Chemistry/Surface Science 3124.853.9452

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#1

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:07 PM

I would suggest contacting Tektronix directly with your question. Keithley Instruments is now a part of Tektronix.

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#2
In reply to #1

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:13 PM

I contacted them as they are now owners of Keithly. They declined to help- said they had no documentation and had no access to documentation records or archives. Thus they declined to be helpful.

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#4
In reply to #2

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:38 PM

This guy, Tim Fox, apparently has a 26220 manual and PM'd the calibration details to another member named garrettm. If you could contact either member perhaps? You'd have to join the forum of course.

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#7
In reply to #1

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:59 PM

Sorry mate, it's such an old instrument that there's just nothing out there for it, manual-wise. If you really need it calibrated, follow redfred's advice and contact a NIST-certified metrology lab. Considering that you bought it on eBay, chances are that such calibration services will likely cost you more than you paid for the instrument itself.

Relying on something purchased on eBay is a crap shoot, even if you get it calibrated. How long will it hold that calibration and how will you know it is drifting out of calibration? That's a pretty old instrument. If you simply must have a calibrated meter, you may wish to invest a bit more in a trustworthy instrument that you can count on - and from a known, reputable source to whom you can turn for service as needed.

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#10
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:17 PM

Absolutely true & correct & everything you've said is applicable. I can't thank you enough, together w/ other respondents, for being so incredibly responsive. Everyone has been & is incredibly helpful.

A more modern & reliable instrument is CLEARLY needed, here.

I paid next to nothing for this unit & need it ONLY to give me yes or no (and NOT a precise value) as to whether or not I have an electron beam present. I know how much current I should see from such an electron beam & need ONLY to confirm that it is present or it is NOT. This is a scanning Auger Spectrometer on which I am doing diagnostics to resolve beam issues.

So, again- thanks to everyone for help. I have manufactured a floating power supply from batteries obtained from a UPS unit. I now have a floating 92 volt supply which has the spectrometer on one side & the pico ammeter on the other. The idea is to use the pico ammeter to detect/confirm the presence/absence of an electron beam.

PM

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#12
In reply to #10

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:20 PM

Given that particular application, is it even necessary to calibrate the instrument?

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#14
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:31 PM

Do please get back to us on the health of the Auger Spectroscopy Lab when the dust from this episode settles down. That stuff is highly interesting to several of us, I should think.

Studying graphene with it (yet)? I keep waiting for someone to prove beyond any doubt the ease of plucking a stray electron from the SPP cloud of graphene.

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#15
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:39 PM

You can count on an update. The results from the query I posted here, together w/ my newly manufactured floating power supply, these are the tools I need to get this system up & running. I rebuilt the computer that runs instrument & acquires data; reconstructed the hard drive & re loaded/re configured the s'ware, & now I can approach the beam issue(s).

My sincerest thanks to all.

PM

UIC dept. of chemistry/surface science

pmelin2@uic.edu paul_melnikov@yahoo.com

314.853.9452

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#16
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:50 PM

Dude, you need to get yourself a big-arse NSF grant for some good lab gear so that you can spend that time doing Science.

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#18
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 4:08 PM

I could not POSSIBLY agree more. UIC (Univ of IL at Chicago) is a publicly funded university & nearly everyone here is desperate for funding. Sad but true. Even in an area such as surface science involved w/ cutting edge battery technologies, novel materials, graphene, & more, we are still struggling for money to do work. Scientific & technological advances don't get by done by people alone & instrumentation alone. It gets done by people, instruments, vision, & reaching for the new & the un known.

I've done work for the UN in Iraq & middle east, US military, more industry venues than I can count, & on four continents plus the antarctic. It takes people, vision, instrumentation, vision. It takes wanting to know more about things worth knowing more about.

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#19
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 4:12 PM

Damn right. It must be so frustrating for you there.

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#20
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 4:17 PM

Look, you can do this! We believe in you! Make it so, #1.

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#11
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:19 PM

I must agree with Andrew. You could try to wing it, but you better have some really good, known current sources, and considering the age of this instrument, what your calibration gear might cost, you should follow his advice. If the amp (log-amp) is not good, you will waste your very valuable time attempting to get good low-level numbers.

At the very best, such an old instrument will not have the same input impedance at the summing junction that a new one will have, will not have as good CMNR (common mode noise rejection), etc. The log part of the amp (CMOS transistor) will not be as good as the best new ones, and so on.

Start over with new. Then you "play" with the old one, and set it up for an undergraduate to knock around with.

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#17
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:58 PM

As long as coolyaar doesn't get hold of it. Bring a fire extinguisher and some (non-conductive) handcuffs.

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#3

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:25 PM
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:08 PM
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#9
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:11 PM

Way to go, bird! You done it again!

Note to OP: S.E. accepts PayPal.

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#13
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Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 3:28 PM

I tell you who I want on my Scavenger Hunt Team at next year's CR4lympics!

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#5

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:45 PM

If you truly need calibration then only a NIST certified lab using certified reference equipment and signals can achieve true calibration.

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#6

Re: How to Use/Calibrate Keithley 26220 Pico Ammeter

05/12/2017 2:58 PM

This document I found on searching is more of a product bulletin:

http://www.helmut-singer.de/pdf/keithley410a-414s-26000.pdf

The model you have lists a standard option of an internal -300 V power supply, and I think it odd that power supply is not available. I presume it does have its 110 VAC 1Ph power cord still attached?

The blurb I found mentions the recover switch, an input shorting switch, and log linear range. I have no idea as to the time-constant of the input circuit, but if it is to be used on intermittent current sources, it needs to be "reasonably" fast, but still relies on charge (even near discreet event charge) integration with a decay constant, most likely as feedback on the negative input of a log amp (and a really, really good one, I might add).

http://www.tek.com/sites/tek.com/files/media/document/resources/OptimizingLowCurrent_WP.pdf

This technical document does not address your meter specifically, but it might be of some help.

Another point to consider: Who do you know on campus (physics department?) that might actually have one of these also? Have you considered touring their labs and asking around to see if anyone has the documentation on this model?

I have also exhausted my ability to find one for you, sorry, but no direct luck.

Calibrate your picoammeter

Ammeter (and log compression) theory of operation

The above link is clearly pertinent to the pocket-picoammeter, and may not bear much resemblance to your picoammeter, unfortunately or fortunately.

Does your chemistry and/or physics department have its own instrument shop? Someone there may have your answers on the tip of their tongue.

Key (as I suspect you are aware) is (1) proper shielding, (2) Vref that pertains to the voltage of your source, and clean connections. Faraday shielding of the entire instrument may be necessary.

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