[Moller_simulation] [EXTERNAL] Re: Detector mounting structure

Krishna Kumar krishna.kumar at stonybrook.edu
Fri Nov 8 06:36:22 EST 2019

HI, Michael. We will take a look at this. Lou has spent some time on the mechanics as well and so it might be a good idea to discuss the ideas together in a meeting perhaps next week before sending something to Carl.
Cheers, KK

> On Nov 7, 2019, at 11:44 PM, Michael Gericke <Michael.Gericke at umanitoba.ca> wrote:
> Hello everyone,
> I am attaching my conceptual design for the detector mounting structure.
> Since we haven't had anything of this sort ready for getting meaningful
> cost estimates (and I had to do this for the CFI quotes anyway), I decided
> to make a design that could be submitted to a company for a quote request.
> I am still waiting for them to get back to me.
> The attached pdf is CAD generated and you can zoom in and rotate the
> models. If you wish to have the CAD files, I'll be happy to upload them
> somewhere. The attached movie illustrates how the individual modules
> can be assembled (sorry, the files are fairly large, so one has to be patient).
> A few points I want to make:
> 1) As I said, this is a conceptual design and I am pretty sure it can be optimized.
>     I tried to balance mounting rigidity with as small a material budget as possible,
>     but I am sure one can further improve on that. Maybe it will provide some food
>     for thought for the group working on the structure design.
> 2) Some of the parts are complicated; The company I spoke to said that they could
>     either 3D print or use a 5 axis CNC to make the more complicated parts, but I expect
>     the cost to be higher than what we budgeted up to now, especially if we decided that
>     we want to us a carbon fiber based material, rather than aluminum.
> 3) I think I know how one could simplify the complicated parts and make it cheaper, but at
>     the cost of less rigidity, I think.
> 4) This design treats the PMT-LG-Quartz assembly as a unit, which will make light tight sealing
>     easier. The mounting plates for each module would allow using washers to adjust angles, if
>     need be.
> 5) The extra space needed by the "skeleton" for each module causes the rings to be spread out
>     a little more, in the beam direction. One can play around with the structure to squeeze that
>     together, but I would caution against overdoing that, as it could get impossible to assemble
>     and service parts. It would be better to adjust quartz tile size and mounting radii.
> 6) I think we will need two separate, concentric cylindrical structures, one that will hold the
>     modules, as in this design, and a separate one that will hold the shielding. I don't think we
>     can afford to have a high weight load on the module structure, as it was suggested in the
>     previous designs.
> 7) We will need to think about whether we need to flush the light guide with dry air, to prevent
>     possible reflectivity degradation, which would further complicate the design. The modules would
>     support a light and air-tight bag around each one and one could imagine feeding the air through
>     the PMT housing.
> So, while this still just a preliminary design, I think it can serve as a first basis for a real cost
> estimate of the mounting structure and will show the CDR committee that we have at least
> thought about the mounting details.
> As soon as I have a quote for the module parts, I will pass it on to Carl.
> Cheers,
> Michael
> -- 
> --
> Michael Gericke (Ph.D., Professor)
> Physics and Astronomy
> University of Manitoba
> 30A Sifton Road, 213 Allen Bldg.
> Winnipeg, MB R3T 2N2, Canada
> <ThinDetectorArrayAssembly.pdf><R5-AssemblyMovie_x264.mp4>

C-111, Physics Building
Stony Brook University

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