Detector support and flange

From: Hans Jostlein <>
Date: Wed Jul 14 2004 - 15:29:39 CDT

Hi, Vic,

thanks for your response.

I am still interested in a strut type support, and asked Ang Lee to do some
very basic FEA .
Presumably I will learn what you already learned, but I'm curious.
The struts are meant, of course, to take the forces directly to the 4
support points.
We'll see.

On the shape, I am sure you realize that a cylinder will weigh 50% more
than a sphere of the same diameter and height.
That's a big tax to pay!
I also don't quite see why a cylinder would be easier to support.
Basically, I don't understand the force flow in your support structure.
Maybe you can show me next time you are here at Fermilab.

The fabrication should be no issue at all;
Chicago Bridge and Iron, as you know, makes those vessels in this and
larger sizes all the time,
mostly for water towers.
They made the 40 ft diameter Miniboone sphere.

I am also attaching a picture with a couple of comments on the large vessel
Maybe you already drew the flange that way.



----- Original Message -----
From: "Victor Guarino" <>
To: "Hans Jostlein" <>
Cc: "David Reyna" <>; <>; "Jim
Grudzinski" <>
Sent: Friday, July 09, 2004 3:14 PM
Subject: Re: Detector support concept

> Hi Hans,
> Thanks for your input. This is very similar to the structure that we
> originally examined. We moved to the structure that I showed in our paper
> several reasons. First, the structure induced stresses into the sphere
> required it to get thicker. Second, we are planning on moving the
detector on
> Hilman rollers located at discrete points. Therefore, the structure has
to be
> very stiff in order to transfer the load from any structure to the support
> points at the Hilman rollers. I didn't want the structure to deflect to
> between the hilman roller supports because this would induce stresses into
> outer steel sphere. I did some simple FEA modeling of the structure but
> course further optimizing can still occur.
> I have been thinking that we should get away from the outer containment
> being a sphere. I have done a lot of work trying to find companies that
> fabricate such large sphere and there aren't many. Also, if we have the
> requirement that we need to dismantle the outer sphere in order to get at
> PMT's then we need some sort of flange so that the sphere can be taken
> This is another complication on the design and fabrication. I think an
> way would be to make a simple structure that is similar to an above ground
> pool. The two acrylic spheres would be suspended inside the pool and a
> geodesic structure can be constructed around them to support the PMT.
> type of structure would be easier to support and fabricate and access to
> PMT's would be a lot easier.
> Vic
> Hans Jostlein wrote:
> > Hi, Vic,
> >
> > for your amusement,
> > I have attached a strut-type detector support concept.
> > I am not sure I understand your drawing completely,
> > and I apologize if I have overlooked an important constraint.
> >
> > Sincerely
> >
> > Hans
> >
> > Name: Detector support concept.JPG
> > Detector support concept.JPG Type: JPEG Image (image/jpeg)
> > Encoding: BASE64

Received on Wed Jul 14 15:29:41 2004

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