Answers to Barcelona questions about Mini-Drawers and comments Tilecal upgrade meeting CERN (24 June 2013) François Vazeille on behalf of Roméo Bonnefoy, Dominique Pallin François Daudon, Gilles Magaud, Marc Nivoix, Guy Savinel, Pierre Verdier  Questions and answers  Other comments  Next actions 1

Questions and answers Questions taken from the Back up slides of Furan Granena (Stockholm meeting ) 2

1. Screws M3, thickness Iron shielding 2 mm: yes, but 116 mm instead of 117 mm. 3.Threads were proposed by Clermont-Fd to other Institutes, located where Al thickness is good, but freedom is given for drilling others. 4. Holes made for the mock up sliding tests to maintain the Iron cylindrical loads: no use later when the mock-ups were machined in Mini-Drawers. 5. Not clear: does it mean PMT block diameter? If yes, there were diameter fluctuations in the Iron cylinder productions*  The drawings of holes took into account the biggest diameters. *Besides: if the fixation of the iron end plate is too much screwed  distortion of the round shape. 3

1. The slides are made of Polyethylene PE HD. Other materials could be used if they can offer the same sliding properties on the Girder-Rings made of NORYL  (PPOm, loaded 30% carbon fiber) (Validation made in our tests at CERN) or even if they are better. 3. Same comments as those ones of the previous slide, question # These pieces are 1 mm thick and enable to recover the step in between 2 holes, since the Drawer length is 2 mm shorter. Their role is also to offer some motion. Sliding tests at CERN showed that the offered flexibility was enough. If other solutions are proposed, new tests will be requested. Plate with a boss  Some freedom 4

2. Till now, this tolerance of  0.1 mm fitted well the whole Tilecal arrangement. The precise positioning of the PMTs with respect to the Fiber-bundles is a constraint we must keep. More generally, any upgrade action should be able to keep the present performances and even to improve them. This comment is valid for any upgraded elements of Tilecal including the electronics. 5

Mechanical precisions 1. We will provide the propagation of present tolerances: it is crucial to insure the right position for the biggest D cells (bigger bundles). Cooling aspects 3. The present design of the cooling circuitry (diameter of Al tubes), and of the inlet water flux and temperature, was optimized from test beam studies, then from ATLAS studies. Any modifications (it is not forbidden !) should follow the same approach. Depending from the final FE options, the dissipated heat will be different: bigger in the case of the option 1, likely smaller for option 3 and less for option The association of the Leakless Cooling System and of the automatical present locking of the connectors prevent the leaks. Is it possible to recover such a working in the new design ? 6

Other comments 2. and 3. Despite some flexibility, the experience showed that a lot of Modules made very difficult the insertion/extraction of present Drawers and Super-Drawers. What were the reasons ? Not very clear: likely the Girder-Ring alignments with respect to the Finger references, plus the effects of damaged Girder-rings.  Inserting one by one the Mini-Drawers should improve the manipulations, keeping some flexibility without changing the mechanical tolerances. 7

1.The idea of having a long basket has been proposed at Stockholm meeting: WHY NOT ? but the design of Mini-Drawers will request a new design of a long basket. 2. The new Slider (tested next week) will use more Girder-Rings than the first one  tests will show if it is enough: likely yes for Mini-Drawers what about a new Super-Drawer of 4 Mini-Drawers ? New tests will give the answer. 8

Not in agreement of having fully independent Mini-Drawers (But for mechanical links and cooling): It was one of the main justification of the new electronics set-up. OK: the Mini-Drawers are independent, - But the HV link is depending from the HV option. - If yes, it is not easy to go from a side to the other side (across the body). 9

Next actions 10  Thursday 20 and Friday 21 by June: tests of new Slider and new Basket, always at the prototype level.  New evolutions of Tools/Drawers, including cooling, mechanical links, services.  As soon as possible: integration of the 3 readout options, and new tests of the tools.  Use of CDD storage of drawings.  It is important to have tight contacts in between Barcelona (Links and services) Bucharest (The bodies) Clermont-Ferrand (The handling tools) plus Institutes having the experience of present Drawers (mainly CERN-Irakli and Clermont-Ferrand) plus the Institutes working on the electronics.