Instrumentation

[Rennhack]

Lessons Learned: Instrumentation

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[mikeland]

Hmmm - another hot topic!

If your metering - well, if all else fails - read the instructions.  

For those designing electronics - this is a whole new 'ballgame'.
Most things are going digital today - and it is very much 'throw away' technology - which is ironically meant to be cheap as well. Hmmm - that's the 'plan'.  

As for the designing of circuits - be on your guard - and test your designs - and also the components that you chose to include in your boards.
Not all are the same - nor age as well as others.
Most tubes still require HV!!! (fingers) - and analog pick ups - along with a host of newer interfaces.

Keep your board designs and layouts accessible - safe from HV leads and fields ... keep your HV supplies _away_ from the digital components, and the anolog away from the digital parts.
As always - low noise design topologies - and testing of your prefab boards in SPICE or anything similar to iron out potential problems before spending $$$$.
Try to build it to look 'good' - that way it will last - and pot and cover your electronics and joints to keep potential contamination out.  
Remember - HV means Electric field - which means particulate accumulation ... in that particular area.
Also, test things to destruction ... I know it is hard to see you work going through the mill - but its got to be done - and you'll learn from it.
No point someone a few years down the track getting dodgy gear because it was designed badly ... that is just stupid.

And lasty for those with microprocessors or DSPs - watch your coding!!!
Drop into assembler if you are writing in C or Java (or whatever) ... and get rid of that extra 'code' overhead - it causes problems!!!!
Your assembler should be neat, tidy, well written and '_bug free_' - this goes back to the above 'digital layout' designs!!!!
Your preboot power ups - or those that are continuously running should go through a fault 'mode' - and detect faults and then display or shut down!!  

No one wants a potentially faulty or intermittent device because someone was lazy.

[Roll Tide]

Keep it simple!
Believe your instrumentation until you can prove it's wrong. How many people have gotten in trouble because they couldn't possibly believe that reading? Get another instrument and re-check before you dismiss the first instrument.
I am using general terms that apply to permanently installed equipment, personal dosimetry, and hand-held instruments. Make sure you cover all the bases.

[SloGlo]

write it down, write it all down.  record all yer data.  record any positive/negative comments re: yer data and instrumentation.  record all the whys, wheres, hows, whats, whens, and of course the whos involved with the data gathering.  if yer out in the environment, record those impacting info bits too; temperature, humidity, barometric pressure, 'n other miscellaneous meterological info.  record yer surface conditions of the monitored items... dry, wet, snow covered, ice covered.  'n so on 'n so forth.  yinze never know when some yahoo digithead databank guru is gonna try 'n make something out of nothing, or (much more likely) nothing out of something.

[moke]

I learned in the recent past about scanning using such instruments such as the 100 cm2 dual phosphor Alpha & Beta detection device.

We assume CONTACT to be a source orientated at the protective screen. Well, that is not the case, yet in many cases, depending upon instument detector specifications, the source is actually up to 1/4" away so now your scan MDCs and detection efficiencies are off. Some may compensate for the distance yet many do not!

Additonally, Contrary to belief, many surfaces have been surveyed incorrectly & LICENSES TERMINATED. Scan MDC.

I referenced a paper published by Dr. Marty Jamieson that spells it out. There is also inconsistencies with the MDA philosophy that many still do not understand yet they continue to establish protocol. Hummmm?

NICE THREAD FOLKS. LETS KEEP HER GOING STRONG! OUR FIELD IS BASED UPON LESSONS LEARNED; SHARING. THANK YOU KINDLY FOR YOUR INPUT BECAUSE THIS WILL HELP OTHER MEMBERS PROGRESS FASTER THAN WE HAVE THE OLD FASHION WAY!

Have an Awesome Day,

Moke

[SloGlo]

I learned in the recent past about scanning using such instruments such as the 100 cm2 dual phosphor Alpha & Beta detection device.

We assume CONTACT to be a source orientated at the protective screen. Well, that is not the case, yet in many cases, depending upon instument detector specifications, the source is actually up to 1/4" away so now your scan MDCs and detection efficiencies are off. Some may compensate for the distance yet many do not!

Additonally, Contrary to belief, many surfaces have been surveyed incorrectly & LICENSES TERMINATED. Scan MDC.

I referenced a paper published by Dr. Marty Jamieson that spells it out. There is also inconsistencies with the MDA philosophy that many still do not understand yet they continue to establish protocol. Hummmm?

NICE THREAD FOLKS. LETS KEEP HER GOING STRONG! OUR FIELD IS BASED UPON LESSONS LEARNED; SHARING. THANK YOU KINDLY FOR YOUR INPUT BECAUSE THIS WILL HELP OTHER MEMBERS PROGRESS FASTER THAN WE HAVE THE OLD FASHION WAY!

Have an Awesome Day,

Moke

yo, moke... while we're beating up scanning here.  didja know that they say you can scan with the gas h3 probe?  nice trick as there is no protective screen, mylar, nada.  thatsa wunnerful time!
if one decides that contact is not at the plane surface represented by the protective screen, mylar, whatever, how are you to ascertain the manufacturer's data re: efficiencies, etc?  wouldn't it make scintillation detectors obsolete for final status surveys of fixed contamination?
i agree with the mda usage being not understood.  it's right up there with the lld as far as field usage.
have a good one.

[Phurst]

Remember that electronic noise can affect the meter reading. Actual contact is always magnitudes higher than contact IAW the meter reading. If using an extending meter or remote, don't forget to check the dose where you are standing. Cold can affect your readings. Meters, like cars can fail and when turned in, repair will say they can't find anything wrong, often. Believe the worse case reading until you prove otherwise. PIC-6s as door stops are only good for doors under 600 pounds. Meters should be handled like laptops, carefully and as gently as possible. RO2A mylar is not for freshening up your lipstick or popping your pimples. Pressing the source into the mylar to get a higher reading is not a good practice. and on and on and on. Oh yea, teletectors are NOT good underwater meters.

[mikeland]

Oh - I forgot to mention water - specifically Salt Water  

For those going to 'the' tropical islands ...  

Be prepaired to 'write off' your gear - keep it sealed away in airtight low humidity containers.
Salt laden air will get in to your electrons - period.