[Fast-Neutrons] Congrats! Re: First fast neutron images at Phoenix
alan.hewat at neutronoptics.com
Mon Nov 18 18:56:35 CET 2019
Michael. OK, we can't do 100 microns over that FOV with that CCD. Its 4000
pixels for 500mm optical. But the real limit is the scintillator, L/D, and
sample-scintillator distance. I guess you can only get your resolution for
small objects up against the NIP.
The designed minimum working distance of the Nikkor 50mm f/1.2 lens is
500mm, so no problem at a distance of 750mm. Of course wide open at f/1.2
the depth of focus is small, but it works well under those conditions of
Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
from my telephone
<Alan.Hewat at NeutronOptics.com> +33.4220.127.116.11
On Mon, 18 Nov 2019, 18:32 Michael Taylor, <Michael.Taylor at phoenixwi.com>
> I got a quote from Fuji just a couple months ago for image plates, no GE
> involved. GE health sciences used to sell the 8”x10” ones made by Fuji as
> of a few years ago but I haven’t looked into them recently. We do buy
> directly from Fuji.
> Yes, you’re right that we need 20 to do a swap out and turnaround.
> Resolution wise, we need about 100um. Per the upcoming new astm standards
> for digital imaging, we are getting about 50um on CR, which some customers
> have already seen and are quite pleased with. If a detector can’t do at
> least 100um resolution for a 14”x17” field of view in less than 30 minutes,
> it’s a non-starter for us.
> I’m surprised about the field of view you mention. Are there aberrations
> or distortions at that focal length and distance from the mirror?
> On Nov 18, 2019, at 11:15, Alan Hewat <alan.hewat at neutronoptics.com>
> Perhaps Fuji does still make neutron image plates (NIPs), but Burkhard is
> right that GE at least markets them according to this document
> 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
> - Nikon Nikkor 50mm f/1.2 lens (a great lens for $600).
> - Distance scintillator-CCD 750mm (not huge) for a FOV of 500x336mm
> - 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
> Regards, Alan.
> On Mon, 18 Nov 2019 at 17:19, Michael Taylor <Michael.Taylor at phoenixwi.com>
>> 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
>> 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!
>> 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.
>> Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
>> from my telephone
>> <Alan.Hewat at NeutronOptics.com> +33.418.104.22.168
>> 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 …
>>> Paul Scherrer Institut
>>> Dr. Eberhard H. Lehmann
>>> Forschungsstrasse 111
>>> 5232 Villigen PSI
>>> 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> +33.422.214.171.124
>>> 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
>>> 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!
>>> > 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
>>> D-85748 Garching
>>> Tel. +49 89 289-12185
>>> Fast-Neutrons mailing list
>>> Fast-Neutrons at neutronsources.org
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>> Fast-Neutrons at neutronsources.org
> Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE
> <Alan.Hewat at NeutronOptics.com> +33.4126.96.36.199
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