[ RadSafe ] Re: Eating Thallium vs NaI(Tl) crystals

Wed Nov 4 14:23:31 CST 2009

You asked the question Franz, I answered it.

George Dowell

----- Original Message ----- 
From: "Franz Schönhofer" <franz.schoenhofer at chello.at>
To: "'Geo>K0FF'" <GEOelectronics at netscape.com>; "RADSAFE" 
<radsafe at radlab.nl>
Sent: Wednesday, November 04, 2009 2:15 PM
Subject: AW: Eating Thallium vs NaI(Tl) crystals

George,

Obviously you are at a scientific level, where it is necessary to explain to
somebody else the principles of gamma radiation detection.  Sorry, I am not
a target for your primitive "lecture", please respect that at RADSAFE you
are dealing with real experts. They are not only knowleagable in radiation
protection but also in radiochemistry and many other associated fields like
radioecology.

Best regards

Franz

Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna
AUSTRIA

-----Ursprüngliche Nachricht-----
Von: Geo>K0FF [mailto:GEOelectronics at netscape.com]
Gesendet: Mittwoch, 04. November 2009 20:59
An: Franz Schönhofer
Betreff: Re: Eating Thallium vs NaI(Tl) crystals

Franz, All sodium iodide crystals used in radiation detection are NaI(Tl)
which is sodium iodide, with Thallium added.

Thallium creates electron traps in the forbidden zone, allowing much more
sensitivity.

Which is what I said in the very first post that you took exception to.

George Dowell

----- Original Message ----- 
From: "Franz Schönhofer" <franz.schoenhofer at chello.at>
To: "'Geo>K0FF'" <GEOelectronics at netscape.com>; "RADSAFE"
<radsafe at radlab.nl>
Sent: Wednesday, November 04, 2009 1:44 PM
Subject: AW: Eating Thallium vs NaI(Tl) crystals

Dear George,

Your reply is very close to the absurd reasoning of ultra-green, ultra
anti-nuclear and ultra "against anything" activists, because you
deliberately twist facts: While I was referring to the potential hazard of
NaI(Tl) crystals being eaten (!) you obviously refer to thallium ingested as
a poison for rats (not mentioned in which chemical form). You have not given
any explanation to your comment on the "toxicity of NaI) crystals. Forget
this "toxicity".

I eat quite some NaCl every day, but I cannot see any reason why I should
incoporate any Tl - and I would urge you not to do it either.

Best wishes for your health and appropriate intake of food!

Franz

Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna
AUSTRIA

-----Ursprüngliche Nachricht-----
Von: Geo>K0FF [mailto:GEOelectronics at netscape.com]
Gesendet: Mittwoch, 04. November 2009 02:31
An: Geo>K0FF; Franz Schönhofer
Betreff: Re: [ RadSafe ] Optical Couplant

Franz, I will eat 2 g of NaCl if you eat 2 g of Thallium.
----- Original Message ----- 
From: "Geo>K0FF" <GEOelectronics at netscape.com>
To: "Franz Schönhofer" <franz.schoenhofer at chello.at>
Sent: Tuesday, November 03, 2009 5:41 PM
Subject: Re: [ RadSafe ] Optical Couplant

> Franz, I will eat 2 gr of NaCl if you eat 2 gr of Thallium.
>
>
> George Dowell
> ----- Original Message ----- 
> From: "Franz Schönhofer" <franz.schoenhofer at chello.at>
> To: "'Geo>K0FF'" <GEOelectronics at netscape.com>; "'AnaLog Services, Inc.'"
> <AnaLog at logwell.com>; "'Edmond Baratta'" <edmond0033 at comcast.net>;
> <alstonchris at netscape.net>
> Cc: <radsafe at radlab.nl>
> Sent: Tuesday, November 03, 2009 5:35 PM
> Subject: AW: [ RadSafe ] Optical Couplant
>
>
> RADSAFErs,
>
> Another case of fundamental lack of very basic understanding: How much Tl
> is
> in such a crystal? What is the LD 50 of Tl? Has ever anybody eaten or at
> least tasted a NaI(Tl) crystal? How does it taste? How does the mineral
> oil
> taste and should one also use a little vinegar when eating it? Anybody
> aware
> that NaCl (also called "salt") is deadly if consumed in large amounts?
>
> This statement reminds me on the infamous statements about the toxicity of
> plutonium, polonium, radium and all other radionuclides. "The dose makes
> the
> poison!" - Famous statement of the famous Paracelsus, which is still
> valid.
> (Btw, he is buried in Salzburg in a beautiful romantic graveyard.)
>
> Best regards,
>
> Franz
>
> Franz Schoenhofer, PhD
> MinRat i.R.
> Habicherg. 31/7
> A-1160 Wien/Vienna
> AUSTRIA
>
>
> -----Ursprüngliche Nachricht-----
> Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
> Auftrag
> von Geo>K0FF
> Gesendet: Dienstag, 03. November 2009 20:59
> An: AnaLog Services, Inc.; Edmond Baratta; alstonchris at netscape.net
> Cc: radsafe at radlab.nl
> Betreff: Re: [ RadSafe ] Optical Couplant
>
> It is the Thallium dopant that is so very toxic in the NaI(Tl) crystals.
>
> In the early days, crystals were mounted right on the PMT but immersed in
> a
> cup of
> mineral oil. Today, these 1950's units still work if the oil is intact.
> Many
>
> of them have leaked though, creating quite a mess.
>
> George Dowell
> ----- Original Message ----- 
> From: "AnaLog Services, Inc." <AnaLog at logwell.com>
> To: "Edmond Baratta" <edmond0033 at comcast.net>; <alstonchris at netscape.net>
> Cc: <radsafe at radlab.nl>
> Sent: Tuesday, October 27, 2009 11:52 PM
> Subject: Re: [ RadSafe ] Optical Couplant
>
>
>> As far as I know, it is rare to have naked crystal material coupled
>> directly to the PMT face.  At least it is rare in my industry.  I have
>> seen it, but only a couple of times.  NaI is quite hygroscopic so dealing
>> with bare crystal material except in a special facility is problematic.
>> I
>
>> believe NaI is regarded as toxic also.
>>
>> Heck, we have problems with crystals turning yellow even in the hermetic
>> containers.
>>
>> Syd H. Levine
>> AnaLog Services, Inc.
>> Phone:  (270) 276-5671
>> Telefax:  (270) 276-5588
>> E-mail:  analog at logwell.com
>> Web URL:  www.logwell.com
>>
>> ----- Original Message ----- 
>> From: "Edmond Baratta" <edmond0033 at comcast.net>
>> To: <syd.levine at mindspring.com>; <alstonchris at netscape.net>
>> Cc: <radsafe at radlab.nl>
>> Sent: Tuesday, October 27, 2009 8:11 PM
>> Subject: Re: [ RadSafe ] Optical Couplant
>>
>>
>>>I believe only the older ones were coupled.  Most of the newer ones are
>>>coupled directly and sealed.  The manufacturers used to supply (sell) the
>>>material to couple the older ones.
>>>
>>> Ed Baratta
>>>
>>> edmond0033 at comcast.net
>>>
>>> --------------------------------------------------
>>> From: <alstonchris at netscape.net>
>>> Sent: Tuesday, October 27, 2009 6:10 PM
>>> To: <syd.levine at mindspring.com>
>>> Cc: <radsafe at radlab.nl>
>>> Subject: Re: [ RadSafe ] Optical Couplant
>>>
>>>>
>>>> Syd
>>>>
>>>> Is there nothing in Knoll (Radiation Detect and Measure) that's useful
>>>> on this subject?  Also, e.g., research-grade NaI crystals are mated
>>>> directly to the PMT, no?
>>>>
>>>> Cheers
>>>> cja
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Syd H. Levine <syd.levine at mindspring.com>
>>>> To: J. Marshall Reber <jmarshall.reber at comcast.net>
>>>> Cc: radsafe at radlab.nl
>>>> Sent: Sat, Oct 17, 2009 10:16 pm
>>>> Subject: Re: [ RadSafe ] Optical Couplant
>>>>
>>>>
>>>> I looked for something, even qualitative, and could not find anything
>>>> interesting. I found some stuff related to fiber optics that surprised
>>>> me (not as big an improvement as I expected), but I do not know how
>>>> that
>
>>>> applies to scintillation detectors. I do not *think* a scintillation
>>>> detector will work at all without coupling compound.
>>>>
>>>> Syd
>>>>
>>>> ----- Original Message ----- From: "J. Marshall Reber"
>>>> <jmarshall.reber at comcast.net>
>>>> To: "Syd H. Levine" <syd.levine at mindspring.com>
>>>> Cc: <radsafe at radlab.nl>
>>>> Sent: Saturday, October 17, 2009 3:48 PM
>>>> Subject: Re: [ RadSafe ] Optical Couplant
>>>>
>>>>>
>>>>> On Oct 17, 2009, at 4:21 PM, Syd H. Levine wrote:
>>>>>
>>>>>> I finally got around to writing a page about optical coupling
>>>>>> compounds:
>>>>>> http://www.logwell.com/tech/servtips/optical_coupling_grease.html
>>>>>>
>>>>>> Comments or criticisms needed and much appreciated.
>>>>>
>>>>> It would be useful to quote in quantitative terms the actual light >
>>>>> transmission improvement of using the coupling compounds.
>>>>>
>>>>> Unfortunately I am unaware of such data.
>>>>>
>>>>> J. Marshall Reber, ScD
>>>>> 165 Berkeley St.
>>>>> Methuen MA 01844
>>>>>
>>>>> Tel/Fax: 978-683-6540
>>>>> Alternate Email: reber at alum.mit.edu
>>>>>
>>>>>
>>>>>
>>>>>
>>>> _______________________________________________
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>>>>
>>>> Before posting a message to RadSafe be sure to have read and understood
>>>> the RadSafe rules. These can be found at:
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>>>>
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>>>>
>>>> =
>>>> _______________________________________________
>>>> You are currently subscribed to the RadSafe mailing list
>>>>
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>>>>
>>>
>>>
>>
>> _______________________________________________
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>>
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>
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