[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: sodium iodide scintillation detectors
Oops. Senility is setting in...or maybe the effects of radiation exposure.
Rexon was started by ex Bicron or Harshaw guys, iirc.
Syd H. Levine
AnaLog Services, Inc.
Phone: 270-276-5671
Telefax: 270-276-5588
E-mail: analog@logwell.com
URL: www.logwell.com
----- Original Message -----
From: "Frank Bloe" <bloe@en.com>
To: "Syd H. Levine" <syd.levine@MINDSPRING.COM>; <John_Sukosky@DOM.COM>;
"Dave Oshlo" <doshlo@mgpi.com>
Cc: <radsafe@list.Vanderbilt.Edu>
Sent: Monday, August 09, 2004 11:40 AM
Subject: Re: sodium iodide scintillation detectors
> FYI
>
> Rexell is Rexon at (216) 292-7373
>
> http://www.rexon.com/
>
> FB
>
>
>
> ----- Original Message -----
> From: "Syd H. Levine" <syd.levine@MINDSPRING.COM>
> To: <John_Sukosky@DOM.COM>; "Dave Oshlo" <doshlo@mgpi.com>
> Cc: <radsafe@list.Vanderbilt.Edu>
> Sent: Friday, August 06, 2004 3:28 PM
> Subject: Re: sodium iodide scintillation detectors
>
>
> > There is no excuse for a crystal failure due to the glue. Though more
> > expensive, we use special ruggedized hermetically sealed crystals,
usually
> > in stainless steel, in well logging sondes. I have some of these built
in
> > the 1970's still working perfectly. If I were you, I would talk to
other
> > manufacturers than just St. Gobain (they own what was Harshaw / Bicron /
> > Solon). There is an outfit in that same area called Rexell that is more
> > responsive, and usually a bit cheaper. Also try Gintek in South
Carolina,
> > and a new outfit down near Huntsville (the name slips my mind).
> >
> > Syd H. Levine
> > AnaLog Services, Inc.
> > Phone: 270-276-5671
> > Telefax: 270-276-5588
> > E-mail: analog@logwell.com
> > URL: www.logwell.com
> >
> > ----- Original Message -----
> > From: <John_Sukosky@DOM.COM>
> > To: "Dave Oshlo" <doshlo@mgpi.com>
> > Cc: <radsafe@list.vanderbilt.edu>
> > Sent: Friday, August 06, 2004 6:58 AM
> > Subject: Re: sodium iodide scintillation detectors
> >
> >
> > >
> > >
> > >
> > >
> > > Dave,
> > >
> > > Based on our experience with two 4 x 4 x 16 inch NaI detectors used in
> our
> > > standup whole body counter, the life expectancy is about 12 years.
The
> > > limiting factor is not the crystals themselves but the glue used to
seal
> > > the detector housing the NaI crystal. The glue starts to degrade
after
> > > about ten years allowing humidity to invade the crystal. When the
glue
> is
> > > degrading and conditions are humid (e.g., summertime in Virginia), the
> NaI
> > > crystal absorbs water and you'll see a significant decrease in
detector
> > > efficiency. When conditions are dry (e.g. wintertime), the NaI
crystal
> > > will start to dry out and you'll see a corresponding increase in
> detector
> > > efficiency. The good news is that you can send your NaI detectors
back
> to
> > > the manufacturer (e.g., St. Grobain) and they dry out the crystal and
> > > reseal it into another detector housing. By doing this you can
> > > indefinitely extend the life of your NaI detector. The drying out and
> > > resealing process takes about a month for the large 4 x 4 x 16 NaI
> > > detectors.
> > >
> > > I'm not sure what the shelf life of NaI detectors are in a warehouse.
> > > However, it's likely to also be dependent on the glue that's used as a
> > > sealant. Check with a crystal manufacturer such as St. Grobain to get
a
> > > definitive answer to this. Hopefully, the glue they're using today is
> > > better than what they used 20 years ago.
> > >
> > > John M. Sukosky, CHP
> > > Dominion
> > > Surry Power Station
> > > (757)-365-2594 (Tieline: 8-798-2594)
> > >
> > >
> > >
> > >
> > > "Dave Oshlo"
> > > <doshlo@mgpi.com> To:
> > <radsafe@list.Vanderbilt.Edu>
> > > Sent by: cc:
> > > owner-radsafe@list.Van Subject: sodium
> > iodide scintillation detectors
> > > derbilt.Edu
> > >
> > >
> > > 08/05/2004 02:46 PM
> > > Please respond to
> > > "Dave Oshlo"
> > >
> > >
> > >
> > >
> > >
> > >
> > > Dear radsafers,
> > >
> > >
> > > I’m looking for two pieces of data on a typical sodium iodide
> > scintillation
> > > detector but can find inadequate documentation.
> > >
> > >
> > > 1. What is the life expectancy of a sodium iodide scintillation
> > > detector in an operational nuclear power plant environment?
> > >
> > >
> > > 2. What is the shelf life of a sodium iodide scintillation
detector
> > > (in the warehouse as a spare part)?
> > >
> > >
> > > An exhaustive web search has not provided any solutions. If someone
> could
> > > point me in the right direction, I would be much obliged.
> > >
> > >
> > > Thanks,
> > >
> > >
> > > Dave Oshlo
> > >
> > >
> > > MGP Instruments
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
************************************************************************
> > > You are currently subscribed to the Radsafe mailing list. To
> > > unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu Put the
> > > text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,
> > > with no subject line. You can view the Radsafe archives at
> > > http://www.vanderbilt.edu/radsafe/
> > >
> > >
> >
> >
> > ************************************************************************
> > You are currently subscribed to the Radsafe mailing list. To
> > unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu Put the
> > text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,
> > with no subject line. You can view the Radsafe archives at
> > http://www.vanderbilt.edu/radsafe/
> >
> >
> > _____________________________________________________
> > This message scanned for viruses by CoreComm
> >
> >
>
>
>
************************************************************************
You are currently subscribed to the Radsafe mailing list. To
unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu Put the
text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,
with no subject line. You can view the Radsafe archives at
http://www.vanderbilt.edu/radsafe/