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fnbrowning

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Ludlum 44-9 Exposure Filter question
« on: Mar 19, 2012, 11:26 »
Regarding the Exposure Filter Ludlum offers that flattens the energy response
of its popular Model 44-9 GM pancake detector to facilitate measuring Roentgens.

http://www.ludlums.com/index.php?page=shop.product_details&flypage=flypage_ludlu\
m.tpl&product_id=461&option=com_virtuemart&Itemid=118


Q1: With this filter snapped on the 44-9, does the 44-9 now act (somewhat more)
like a Energy Compensated G-M Detector, as the Ludlum product information seems
to imply?

Q2: If Exposure Filter of the 44-9 does cause it to act like an Energy
Compensated GM detector, can a mR/hr to R/hr be stated as a Liner Range? {as is
stated for Gamma Radiation Energy Compensated G-M Detectors like the Ludlum 133
series?}

For instance:
Linear Range without Dead Time Correction: 0.1 mR/hr - ??? mR/hr

Linear Range with Dead Time Correction: 0.1 mR/hr - ?? R/hr

Offline GLW

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Re: Ludlum 44-9 Exposure Filter question
« Reply #1 on: Mar 20, 2012, 10:28 »
In plain conventional english,...

The EXP filter is for RAD applications,...

The DOSE filter is for REM applications,...

You can always read and believe the on-line Ludlum literature (they do not lie),... [coffee]
« Last Edit: Mar 20, 2012, 10:29 by GLW »

been there, dun that,... the doormat to hell does not read "welcome", the doormat to hell reads "it's just business"

Offline HydroDave63

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Re: Ludlum 44-9 Exposure Filter question
« Reply #2 on: Mar 20, 2012, 11:22 »
For 104 bucks ya can't go wrong!

fnbrowning

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Re: Ludlum 44-9 Exposure Filter question
« Reply #3 on: Mar 20, 2012, 12:34 »
Oh, I would never mean to imply that Ludlum was misleading in their documentation. Poorly worded question.

I understand the stated difference between the Ludlum EXP & DOSE filters for the 44-9.
And I agree the price is right.

However I'm still missing one piece.

Q2: Since the Exposure Filter of the 44-9 does cause it to act like an Energy Compensated GM detector, can a mR/hr to R/hr be stated as a linear range? {as is the case for Gamma Radiation Energy Compensated G-M Detectors like the Ludlum 133 series?}
For instance:
What is the expected mR Linear Range without Dead Time Correction: 0.1 mR/hr - ??? mR/hr
Linear Range with Dead Time Correction: 0.1 mR/hr - ? R/hr

Offline GLW

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Re: Ludlum 44-9 Exposure Filter question
« Reply #4 on: Mar 21, 2012, 03:38 »
Look up the photon energy vs. response and count rate vs. efficiency for your NOC, the DOSE and EXP filters are produced to help "flatten out" these curves at the expense of degrading response at lower energies due to attenuation, I think they are optimized for a Cs-137 field,...

You will still have to calibrate and validate linearity for any survey results to be defensible,...

Without a dead time compensating meter driving your detector you are going to top out at ~50K cpm per whatever unit of corresponding dose rate you settle on,...

And, as always, a pancake is going to saturate up at the 1M counts limit, again, regardless of whatever cpm per unit of dose conversion you are using,....

I still think you would be better served by going to Ludlum and reading the answers from the source;

http://ludlums.com/images/stories/pdf_files/Ludlum%2044-9%20Compensation%20Filter%20Report_Public.pdf

If that does not get it done for you call 1-800-622-0828, ask for Kent or Mike,...

Peace,.... 8)

been there, dun that,... the doormat to hell does not read "welcome", the doormat to hell reads "it's just business"

Offline Rennhack

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Re: Ludlum 44-9 Exposure Filter question
« Reply #5 on: Mar 21, 2012, 10:49 »
Look up the

You lost me at look up the...

Offline kestrel452

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Re: Ludlum 44-9 Exposure Filter question
« Reply #6 on: Aug 21, 2013, 02:17 »
Sorry to bring up an old topic, and especially so for it being my first post. I am an amateur ore/geiger counter collector and civil defense enthusiast, and searched the internet for information regarding these filters when I happened upon this thread.

It seems Ludlum wanted to, for whatever reason, turn the 44-9 into an energy unit reading probe with these filters. I had always been under the impression that the 44-9 was meant for measurement in counts and for contamination searching/frisking, not taking dose rate or exposure measurements. It's a cool concept though, a highly sensitive search probe that can be turned into a roentgen/rad/rem measurement probe just by snapping in a filter shield. I see a lot of geiger counters on ebay that measure in roentgens, but come with alpha/beta/gamma pancake probes which never made sense to me, and it seems such a filter would alleviate this obvious issue with being able to use the mR scale on a counter with that sort of probe. Although I imagine the filter blocks out most if not all of the beta particles it'd otherwise detect, so how could one get a true dose rate in REMs while ignoring beta?

One other thing I don't get about the filters is that the exposure filter has a flatter response curve than the dose rate filter. If you're looking to get the counter to give you an accurate representation of what the biologically effective dose is, wouldn't you want the exposure filter because of this?

I've also read from multiple sources that in *most* cases, a Cs137 calibrated detector will give you an accurate exposure and absorbed dose rate without having to convert from roentgens even without an energy compensated tube. Basically, if you're reading 10mR on your counter, you're likely being exposed to 10 millirads/millirems. Is this true? If it is, do either of these filters help you come to the *biologically* effective dose rate (sieverts)? I'm aware that to get the biological effect from a set amount of REMs or RADs you need to apply the "quality factor" to each, but I'm not sure if there's a seamless way to get Sv from a R/Rem/Rad measurement from a filtered 44-9 or even a CDV-700  mR reading. I'm also not sure (if all this is indeed the case), if the CDV-700 would give a more accurate absorbed dose or biological effect rate measurement since it can account for beta whereas the 44-9 (at least I presume) cannot. However, my CDV-700 manual states to read the CPM scale with the beta shield open, and the mR scale with the beta shield closed. I've also seen this actually printed on the meter scale itself on a few commercial geiger counters. This further confuses me. Can these counters not get an accurate roentgen measurement with beta being taken into account? If not, then how does the supposed general rule of one mR equaling one mRem and mRad stand? Wouldn't this underestimate the biological impact of the radiation field, and thus the actual mR/mRad/mRem reading??? Sorry for the confusing post, my brain can barely comprehend all of this at the same time.

EDIT: The dose equivalent filter actually has a flatter response curve than the exposure filter, and REMs are also quality factor compensated already. Sorry. Please take this into account when replying.
« Last Edit: Aug 21, 2013, 02:41 by kestrel452 »

Offline kestrel452

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Re: Ludlum 44-9 Exposure Filter question
« Reply #7 on: Aug 21, 2013, 12:05 »
In plain conventional english,...

The EXP filter is for RAD applications,...

The DOSE filter is for REM applications,...

You can always read and believe the on-line Ludlum literature (they do not lie),... [coffee]

Is this really the case? I had always thought that "exposure" meant how strong of a field you're exposed to, not the absorbed energy (which is expressed in Rads). Ludlum's page states that the exposure filter is to be used with roentgens too, which makes sense.

From my understanding, you'd use the dose equivalent filter for Rads. But in *most* cases I've heard it to be true that one Rad is equal to one Rem because the quality factor of both gamma and beta are one, so you might be able to have the geiger read out in either Rem or Rad and have it be correct (although I'm no expert so I'm not sure).

Short version: Exposure filter is for use with roentgens, dose equivalent filter is for use with Rads.

Offline GLW

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Re: Ludlum 44-9 Exposure Filter question
« Reply #8 on: Aug 21, 2013, 12:23 »
In plain conventional english,...

The EXP filter is for RAD applications,...

The DOSE filter is for REM applications,...

You can always read and believe the on-line Ludlum literature (they do not lie),... [coffee]

Is this really the case?......

No, you got us, we're all inveterate liars here at nukeworker.com,...

You should call these guys:


If that does not get it done for you call 1-800-622-0828, ask for Kent or Mike,...


And inform Mike or Kent that you are on to them and the pack of lies they sell,...

They can obviously use the education you can provide,...









[sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm]

refer:  http://www.nukeworker.com/forum/index.php/topic,36818.msg175213.html#msg175213
« Last Edit: Aug 21, 2013, 12:23 by GLW »

been there, dun that,... the doormat to hell does not read "welcome", the doormat to hell reads "it's just business"

Offline kestrel452

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Re: Ludlum 44-9 Exposure Filter question
« Reply #9 on: Aug 21, 2013, 01:40 »
No, you got us, we're all inveterate liars here at nukeworker.com,...

You should call these guys:

And inform Mike or Kent that you are on to them and the pack of lies they sell,...

They can obviously use the education you can provide,...


[sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm][sarcasm]

refer:  http://www.nukeworker.com/forum/index.php/topic,36818.msg175213.html#msg175213

You could make your point without being a jerk at the same time. I'm not making up what I said in that second post, the website spelled it out clearly. Me asking for your post to be clarified isn't a personal attack on you that warrants a sarcastic response, I'm quite obviously just a confused amateur enthusiast asking for an elaboration on what has been said already.

If you don't believe me, try looking at http://deqtech.com/Ludlum/Products/model44-9_filters.htm
Here's a quote from that page: "Application: Gamma Radiation Exposure (Roentgen) with Filter Attached"

Also see http://www.ludlums.com/component/virtuemart/equipment-type-3/medical-117/radiation-safety-183/response-kits-201/ambient-dose-equivalent-filter-460-detail?Itemid=0
Which also says: "Ludlum offers an energy compensation filter that flattens the energy response of its popular Model 44-9 GM pancake detector to facilitate measuring Ambient Equivalent Dose (Sieverts).  Ludlum also offers anotther filter for Exposure...see below."


I haven't accused anybody of lying, the worst thing I insinuated was that you were wrong in how you described what each filter does.

Offline GLW

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Re: Ludlum 44-9 Exposure Filter question
« Reply #10 on: Aug 21, 2013, 02:25 »
You could make your point without being a jerk at the same time. I'm not making up what I said in that second post, the website spelled it out clearly. Me asking for your post to be clarified isn't a personal attack on you that warrants a sarcastic response, I'm quite obviously just a confused amateur enthusiast asking for an elaboration on what has been said already.

If you don't believe me, try looking at http://deqtech.com/Ludlum/Products/model44-9_filters.htm
Here's a quote from that page: "Application: Gamma Radiation Exposure (Roentgen) with Filter Attached"

Also see http://www.ludlums.com/component/virtuemart/equipment-type-3/medical-117/radiation-safety-183/response-kits-201/ambient-dose-equivalent-filter-460-detail?Itemid=0
Which also says: "Ludlum offers an energy compensation filter that flattens the energy response of its popular Model 44-9 GM pancake detector to facilitate measuring Ambient Equivalent Dose (Sieverts).  Ludlum also offers anotther filter for Exposure...see below."


I haven't accused anybody of lying, the worst thing I insinuated was that you were wrong in how you described what each filter does.

emoticon fail,....

sorry you got your feelings hurt,...

you said it best, the website provides the best data:


If you don't believe me, try looking at http://deqtech.com/Ludlum/Products/model44-9_filters.htm
Here's a quote from that page: "Application: Gamma Radiation Exposure (Roentgen) with Filter Attached"

Also see http://www.ludlums.com/component/virtuemart/equipment-type-3/medical-117/radiation-safety-183/response-kits-201/ambient-dose-equivalent-filter-460-detail?Itemid=0
Which also says: "Ludlum offers an energy compensation filter that flattens the energy response of its popular Model 44-9 GM pancake detector to facilitate measuring Ambient Equivalent Dose (Sieverts).  Ludlum also offers anotther filter for Exposure...see below."

which makes me wonder why you would want someone in an anonymous forum to either refute or clarify what was done so well by the manufacturer:

.....I'm quite obviously just a confused amateur enthusiast asking for an elaboration on what has been said already.

If you don't believe me, try looking at http://deqtech.com/Ludlum/Products/model44-9_filters.htm
Here's a quote from that page: "Application: Gamma Radiation Exposure (Roentgen) with Filter Attached"

Also see http://www.ludlums.com/component/virtuemart/equipment-type-3/medical-117/radiation-safety-183/response-kits-201/ambient-dose-equivalent-filter-460-detail?Itemid=0
Which also says: "Ludlum offers an energy compensation filter that flattens the energy response of its popular Model 44-9 GM pancake detector to facilitate measuring Ambient Equivalent Dose (Sieverts).  Ludlum also offers anotther filter for Exposure...see below."...

all that, or you just want to play amateur technogeek "gotcha" (aka being a jerk),...

in either case please again refer to:

http://www.nukeworker.com/forum/index.php/topic,36818.msg175213.html#msg175213



been there, dun that,... the doormat to hell does not read "welcome", the doormat to hell reads "it's just business"

Offline kestrel452

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Re: Ludlum 44-9 Exposure Filter question
« Reply #11 on: Aug 21, 2013, 02:41 »
emoticon fail,....

sorry you got your feelings hurt,...

you said it best, the website provides the best data:

which makes me wonder why you would want someone in an anonymous forum to either refute or clarify what was done so well by the manufacturer:

all that, or you just want to play amateur technogeek "gotcha" (aka being a jerk),...

in either case please again refer to:

http://www.nukeworker.com/forum/index.php/topic,36818.msg175213.html#msg175213


I didn't get my feelings hurt, but apparently my asking you if you were sure about what you said touched a nerve with you. So anyone who dares try to correct you is just trying to play gotcha and be a jerk? How arrogant must someone be to assume they're so infallible that even if they're proven wrong they're still right because to correct them is a sort of malicious game... I'm not sure why you take such strong offense to a simple question of "Are you sure that...."?

I came here because I thought people who were more knowledgeable than in me in this field could offer a clear explanation, not to get lambasted by someone over the phraseology of my question or my motives for asking it.

Offline GLW

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Re: Ludlum 44-9 Exposure Filter question
« Reply #12 on: Aug 21, 2013, 02:48 »
I didn't get my feelings hurt, but apparently my asking you if you were sure about what you said touched a nerve with you. So anyone who dares try to correct you is just trying to play gotcha and be a jerk? How arrogant must someone be to assume they're so infallible that even if they're proven wrong they're still right because to correct them is a sort of malicious game... I'm not sure why you take such strong offense to a simple question of "Are you sure that...."?

I came here because I thought people who were more knowledgeable than in me in this field could offer a clear explanation, not to get lambasted by someone over the phraseology of my question or my motives for asking it.

you win, I lose, you're right, I'm wrong,...

the advice from over a year ago is still the best advice,...


If that does not get it done for you call 1-800-622-0828, ask for Kent or Mike,...


I'm done,....

been there, dun that,... the doormat to hell does not read "welcome", the doormat to hell reads "it's just business"

 


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