Minutes of ILD MDI/Integration WG meeting, 29 July, 2008

1. Progress report of ILD2

status at LLR by C. Clerc

We (+Karsten and Klaus) will meet with Francois Kircher at Saclay, about one hour from now. We have a list of questions on solenoid coils and will discuss them with him.

The simulations of the stray field done by O.Delferrie`re( CEA Saclay) for GLDc are very similar to those of Y.Sugimoto. It is obvious that to reach 4 T we will have to find a solution to limit the stray field, either by increasing both the length and radius of the yoke, or with rings around those gaps.

He is also trying to do 3D simulations of the field, using the CAD model of ILD2, but the meshing need to be optimized.

status at LAL by M.Jore

Matthieu is preparing a note on how to use the CATIA system especially for browser. He is interested in a designing principle of Yamaoka's support tube. He put some new drawings of ILD2 on the ilcild.org page.

2. Progress report of ILD1

"cylindrical" support tube by H. Yamaoka

First, Yamaoka succeeded to convert a step file of square support tube, which has been produced by Matthieu, into the 3D Solid-Edge program. Also, he got weights of devices inside of the tube.

There are issues to design a cylindrical support tube as listed below;

Overall sizes - 0.75m diameter and 6m length ?
Tolerances of static and dynamic variations - a few mm for static load and 2nm or 50nm for ground motion
- The 50nm tolerance is specified in the IR interface documents ( draft for EPAC08). Corresponding part is "We assume that the needed stability of detector surface on which the FD rests, is about 50nm, and that detector concepts are responsible for providing this stability (the mentioned number is rms relative displacement of two FDs between any of 5Hz pulses)."
Supporting method - cantilever from outside of the detector or on the endcap yoke, and two support tubes should be connected with inner tune for smaller relative motion ?
Material - CFRP or Tungsten or other
Load conditions - given by Matthieu
- QD0 700Kg
- LHCal (40 layers of 1cm W + 2mm Si) : about 3000Kg
- LumiCal : 250Kg
- BeamCal : 100Kg
- ECal ring : 420Kg

He explained summary of support tube studies for GLD, 2005. The GLD support tube consists of 10cm thick tungsten with total weight of 32tons (its own weight) plus 9tons. In the modal analysis (ANSYS), the cantilever support tube has ben assumed to be supported outside of the detector with two rigidness, i.e. perfect (Model-A) and realistic spring (Model B). Also, he has estimated a case of additional support on the endcap yoke for each model, i.e. Model-1A, Model-2A etc. . The static deformation has been estimated to be less than 1.6mm for all the cases. Natural frequencies have been also calculated.

Calculation results of relative motions separating ±2m were presented for two tubes connected with an inner tube of 5cm thick CFRP and with input ground motion(GM) of measured one at ATF, KEK as very conventional GM. Model-1A and -2B have natural frequencies of 76 and 17Hz, respectively, and have relative motion of 0.2nm and 3nm, respectively.

He will study an ILD cylindrical support tube in terms of issues listed above.

Matthieu have questions on the choice of natural frequency and alignment method of the tubes. Matthieu will exchange emails with Yamaoka for details.

New idea of anti-DID by Y. Iwashita

Iwashita questioned on present (Brett's) anti-DID configuration. Since the dipole field is needed around the beam line, i.e. inside of beam pipe and support tube, why do we need such anti-DID integrated in the solenoid coil. We may have coils winding on the surface of support tube. Typical field is several hundreds Gauss.

After discussion, he is suggested to design the first version of "local" anti-DID in consultation with KEK colleagues, especially for ILD geometry in IR.

3. Discussion

First , we discussed on the anti-DID issue which has been discussed by exchanging emails. One major issue is whether we should provide an ILD solenoid coil geometry to Brett in order to design the anti-DID for ILD. We agreed that it is fine to provide him as a working assumption. The coil design will be one which Francois Kircher is designing for ILD2.

C. Clerc will discuss this issue at meeting, Saclay. She will distribute a minutes of Saclay meeting. The coil design will be send to Brett by end of this week.

Second, we discussed on the questions to sub-groups to be sent soon. One addition was suggested, which is "route of cable and pipe extraction, i.e. where and how are they extracted" . After final distribution in the MDI/I group, the questions will be distributed to sub-group contacts .

Next meeting will be 12 August, 2008, i.e. 2 weeks from now.