[Fast-Neutrons] Congrats! Re: First fast neutron images at Phoenix

Alan Hewat alan.hewat at neutronoptics.com
Mon Nov 18 18:14:50 CET 2019


Perhaps Fuji does still make neutron image plates (NIPs), but Burkhard is
right that GE at least markets them according to this document
<https://cdn.gelifesciences.com/dmm3bwsv3/AssetStream.aspx?mediaformatid=10061&destinationid=10016&assetid=16330>.


I'm not saying that NIPs are not a good solution if you need 10 different
imaging stations around your source, and I am impressed by your thermal
neutron images, even if they did take 20 minutes at 10**4 n.cm-2.s-1. But
you still need an image plate reader (~$50K) and you have to count the time
needed to dismount the plate, read it and erase it. I guess you change them
all at the same time, since you need to stop the beam to do it, and you
probably want a second set of 10 plates to swap in.

BTW, we have made CCD cameras that size for ~€15K each, not €70K, though
ten would still be expensive :-) The specs would be:

   - "Kodak" full frame (36x24mm)  KAI11002
   <http://www.onsemi.com/pub/Collateral/KAI-11002-D.PDF>  CCD
   - Nikon Nikkor 50mm f/1.2 lens (a great lens for $600).
   - Distance scintillator-CCD 750mm (not huge) for a FOV of 500x336mm
   (20"x13")
   - Optical resolution 125 microns
   - Real resolution ~200 microns depending on L/D, and sample-scintillator
   distance.

If you have even more money, you could buy a system like CYCLOPS
<http://neutronoptics.com/cameras.html#cyclops> :-)

Regards, Alan.


On Mon, 18 Nov 2019 at 17:19, Michael Taylor <Michael.Taylor at phoenixwi.com>
wrote:

> Fuji does indeed make the image plates, I know our vendor quite well and
> talked with him just Friday about making more; they have about 100 in
> stock.
>
> I completely agree that a CCD system would be better for efficiency but
> there is an inherent problem for our application. Our customers need high
> throughout and their traditional setup is using a 14” x 17” field of view.
> When you make a screen that large, you have to move your camera much
> farther away to see the full FOV and then you drop the efficiency.
>
> The other factor is the cost. These image plates are $3500 each, and we
> need 10 for the full system, so $35,000. That’s half the price of a single
> good camera.
>
> I’ve got a lot of emails from folks this morning so thank you all for your
> feedback!
>
> Best,
> Michael
>
>
> On Nov 18, 2019, at 05:25, Alan <alan.hewat at gmail.com> wrote:
>
> 
> OK, perhaps Fuji now produce more efficient neutron imaging plates. I only
> know that we have used Fuji plates at ILL for 25+ years for Laue
> diffraction and had great difficulty persuading Fuji, with the help of a
> famous Japanese scientist, to make special high efficiency plates for us.
> The market is very small, so Fuji just converted ordinary x-ray plates to
> their commercial neutron product. Those commercial plates were less
> efficient and also had magnetic backing to stick to a support, not ideal
> for neutrons.
>
> I would be interested in a comparison of images with an image plate, a
> photographic film in contact with a scintillator, a CCD camera, and a flat
> solid state detector. The latter is also developed for x-rays, contains
> materials that are activated by neutrons, and as Eberhard says, may be
> damaged by the beam.
>
> Alan
> ______________________________________________________
>    Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
>                                from my telephone
> <Alan.Hewat at NeutronOptics.com> +33.476.98.41.68
>         http://www.NeutronOptics.com/hewat
> <https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.NeutronOptics.com%2fhewat&c=E,1,G9wJA6GTd4EoRb30ptzMxctM08c8yK_hwUhOXHH_LQ_RHN9KbRLKBl-fgB9czxxQyn-Lt8Gn2SUwEsDZKPE6RQr95anF15RbXsgWkNcnJ3CcXwL8CM4UB9PQRw,,&typo=1>
> ______________________________________________________
>
> On Mon, 18 Nov 2019, 11:52 Lehmann Eberhard (PSI), <
> eberhard.lehmann at psi.ch> wrote:
>
>> I disagree with Alan about the n-sensitive imaging plates: they are
>>
>> made by Fuji on a commercial base adding Gd to the X-ray sensitive
>>
>> material. Therefore the efficiency is not bad and much better than
>>
>> film methods …
>>
>>
>>
>> Regards
>>
>>
>>
>> Eberhard
>>
>>
>>
>> __________________________________________
>> Paul Scherrer Institut
>> Dr. Eberhard H. Lehmann
>> WBBA/122
>> Forschungsstrasse 111
>> 5232 Villigen PSI
>> Schweiz
>>
>> Telefon: +41 56 310 29 63
>> E-Mail: eberhard.lehmann at psi.ch
>>
>>
>>
>> *Von:* fast-neutrons-bounces at neutronsources.org <
>> fast-neutrons-bounces at neutronsources.org> *Im Auftrag von *Alan
>> *Gesendet:* Montag, 18. November 2019 10:43
>> *An:* fast-neutrons at neutronsources.org
>> *Betreff:* Re: [Fast-Neutrons] Congrats! Re: First fast neutron images
>> at Phoenix
>>
>>
>>
>> Hello Michael, Burkhard and Eberhard.
>>
>>
>>
>> Thank you Michael for these nice images. I too am impressed by the
>> resolution of your thermal images with an L/D of only 35, and agree that it
>> would be good to take thermal images with a camera rather than a neutron
>> image plate. The ordinary Fuji n-plates are just x-ray plates with extra
>> 6LiF and I think only ~10% efficient. ~20 years ago Fuji made special
>> n-plates for ILL that were ~25% efficient but they are no longer available
>> (?). You should be able to reduce the exposure well below 20 minutes with a
>> camera and a good 6LiF/ZnS thermal neutron scintillator even with only
>> 10**4 n.cm-2.s-1. See the images Robert Zboray showed in Sydney from a very
>> low flux Triga reactor, one of which I reproduced in my Munich talk.
>>
>>
>>
>> It would also be good to compare your fast neutron image with a thermal
>> neutron image using the same detector and L/D (with different
>> scintillators). With such small objects, that can be put close to the
>> scintillator, it would be interesting to see if fast neutrons still have
>> some advantage for imaging such defects.
>>
>>
>>
>> I also found Burkard's and Eberhard's comments about the best material
>> and thickness for a fast neutron Siemens star interesting. It would be good
>> to see images with these different resolution objects. I also printed a
>> plastic Siemens star, but 40 mm thick, which I have not yet been able to
>> test. A final trivial point; please don't use exponent e4 instead of 10**4
>> for flux; e has a different meaning for mathematicians.
>>
>> Thanks again for sharing. Alan
>>
>> ______________________________________________________
>>    Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
>>                                from my telephone
>> <Alan.Hewat at NeutronOptics.com> +33.476.98.41.68
>>         http://www.NeutronOptics.com/hewat
>> <https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.NeutronOptics.com%2fhewat&c=E,1,NGkPjyc7i2KXcfEbINm0y3pImONVi5j3FjcqdbhPbCFNUrIlQxIdIXArNUorxEz6_NlYHKznzMzVoyiMKuQX6UKIuJMAzJNIx6PveRaRuSeji0oC3Ns3lg,,&typo=1>
>> ______________________________________________________
>>
>>
>>
>> On Mon, 18 Nov 2019, 08:42 Burkhard Schillinger, <
>> Burkhard.Schillinger at frm2.tum.de> wrote:
>>
>> Hello Michael,
>>
>> congratulations for these nice images!
>> For a fast neutron image, that resolution is pretty good. Probably
>> better than ours - which shows that a high collimation is also
>> important for fast neutrons if you have large samples.
>>
>> I am also surprised again by your thermal image at L/D of only 35 -
>> but that's what you get when you can put the samples up close to the
>> detector.
>>
>>
>> For an edge - about everything scatters fast neutrons, but I have
>> tried with a 10 mm thick polyethylen pattern (Siemens Star) that was
>> 3D printed at our lab. When putting it directly on the detector, it
>> was a good measure to test the screen. The 1.5 mm thickness screen was
>> much better than the 2.4 mm.
>> Not sure what really happens if you take it further away - I assume
>> that 10 mm thickness is a good compromise between attenuation and
>> scattering blur. You might try 10 mm steel as well, but iron is also a
>> diffuse scatterer.
>> A perfect edge does not exist.
>>
>> Good luck with your new 'toys', and Happy Holidays!
>>
>> Burkhard
>>
>>
>>
>>
>> > Good day to all,
>> >
>> > I am happy to announce that we've taken our first fast neutron
>> > images at the Phoenix facility in Wisconsin, USA!  Our source is
>> > operational now with a source strength of approximately 1.5e12 n/s
>> > and an L/D of 450 to achieve a flux at the image plane of
>> > approximately 5e5 n/cm^2-s.  Over the next few weeks, we will be
>> > increasing our beam current and changing our target to a different
>> > material.  We expect to get to full power and have a source strength
>> > of 3e13 n/s and a flux at the image plane of approximately 1e7
>> > n/cm^2-s.
>> >
>> > The image attached was taken using a Varex XRD 1621 digital detector
>> > array and a PP:ZnS(Cu) screen provided by RCTritec.  The
>> > scintillator field of view is 310mm x 310mm, but we plan to use the
>> > full field of view of the detector eventually, which is 430mm x
>> > 430mm.  The image was taken last night and acquired with 15 frames
>> > at 20 seconds each.  The frames were then added and the offsets were
>> > applied for background corrections.  The sample is a simulated M982
>> > military round.  It is 155mm in diameter.  The outside casing is
>> > 1/8" steel and the inside simulant is an HMX equivalent, 6% 6656
>> > binder (simulated with 204 epoxy). Chemically it is similar to HMX
>> > and RDX but with much less nitrogen.  I have outlined some of the
>> > defects of interest that we want to see.
>> >
>> > We would like to measure the resolution of the system next so I
>> > would like to ask if anyone has advice on what material to use as an
>> > edge and how thick it should be?  We do not yet have any kind of
>> > standard measurement technique for this that I'm aware of, so I
>> > would like to know what others are doing.
>> >
>> > I've also attached a new image we acquired using thermal neutrons of
>> > several different military grade .50 caliber ammunition.  We took an
>> > X-ray image for comparison and that is shown as well.  The X-ray was
>> > done at 350kV but I don't recall the current.  The neutron image was
>> > acquired using our thermal neutron generator with heavy water
>> > moderator, the L/D was 35 and the flux was approximately 1e4
>> > n/cm^2-s.  The exposure time on a neutron sensitive image plate was
>> > 20 minutes.
>> >
>> > I hope everyone is well, it was great to meet so many of you in
>> > Garching last month and I wish you all happy holidays as they
>> > approach us soon.
>> >
>> > Best regards,
>> > Michael
>> >
>> > Michael Taylor Ph.D.
>> > Neutron Radiography Product Manager
>> > Phoenix LLC
>> > 2555 Industrial Drive
>> > Madison, WI 53717
>> > 608-515-3214
>>
>>
>>
>> --
>> Dr. Burkhard Schillinger
>> Technische Universität München - FRM II
>> Heinz Maier-Leibnitz Zentrum
>> Lichtenbergstr.1
>> D-85748 Garching
>> Germany
>> Tel. +49 89 289-12185
>>
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-- 
______________________________________________
Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
<Alan.Hewat at NeutronOptics.com> +33.476.98.41.68
        http://www.NeutronOptics.com/hewat
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