AIDA Infrastructure for very forward calorimeters Design proposal Mechanical support structure Designers:In collaboration with: Eric DavidFrancois-Xavier Nuiry Christophe BaultAndrea Catinaccio

Requirements Design and manufacturing of a mechanical structure for Tungsten plates and silicon sensors. A=3.5±0.?? mm B=0.32±0.015(?)mm C=2, 1, or 0.5 ±0.05mm D=not really important Note: It will not be possible to have a “mixture” of different distances C 60

First proposal Multi-parts structure ST  Able to work with C=2mm and 1mm  Needs to be optimized for the C=0.5mm version Main structure: 3 supports hold with 3 rods Tungsten plate Sensor + DAQ Front View Side view 240mm 220mm 192mm 140mm 100mm 78mm

Mechanical structure Stainless steel frame 3 spacers 3 holders Mechanical frame 3 Comb slots Plan support slot

Tungsten positioning  Tungsten plates needs to be fully fixed (3 rotations +3 translations locked out)  Stainless steel machined comb + plans + springs Note: need one set per value of C (2 or 1 mm) Left comb Top comb + spring (x2) Bottom comb Right comb + spring Left plan z y x Tx Tz Rx Ty Rz Ry Left, right and bottom comb lock Ty, Rx, Rz, then Tx, Tz, Left plan locks Ry Other combs equipped with springs only hold in position. 25mm 250mm

How to mount Tungsten plates Open 2 top combsInsert the first Tungsten + detector coupleInsert all Tungsten + detector couples Close the 2 top combs

Second proposal Multi-parts structure ST Front View Side view Silicon sensor Stainless steel frame Spacers 210mm 230mm 170mm 155mm

Mechanical structure Stainless steel frame 3 spacers Central support 2 grooves (Slots design to be updated) (Design to be updated) 1 rib 1 rib, in the central support Translate relatively to the central support Fixed on the central support Translate relatively to the green part

Tungsten positioning  Tungsten plates needs to be fully fixed (3 rotations +3 translations locked out)  Such plates are machined Tungsten plate 1 z y x Tx Tz Rx Ty Rz Ry Tungsten plate 2 Fixed support translate Fixed support translate Tungsten Flat surface Tungsten 1 Tungsten 2 Fixed on the grey support Fixed support Tungsten translate z y x Tx Tz Rx Ty Rz Ry a b a<b

How to mount Tungsten plates Insertion of tungsten plate 1 in the fixed support Insert each two slots tungsten plate 1Sliding and fixing the two first spacers  Half of the tungsten plates are well mounted Concept: The pink offset is 1mm The yellow offset is 1mm This two systems are offset of 0.5mm  Spacing two tungsten plates with an offset of 0.5mm is possible! Two green spacers are fixed on the fixed support Insertion of all tungsten plate 2 in the fixed support Sliding and fixing the two yellow spacers  Half of the tungsten plates are well mounted

What we still need to study How to hold silicon sensors between the tungsten plates

Spare Slides

What we know Honing tungsten plate is something possible (subcontractors in Geneva)  Get 10 microns accuracy on the thickness Spark-machining is possible at CERN to machine Stainless steel parts with high accuracy (5- 10 microns)