RICH WG: Introduction M.Lenti

Outlook PMs and sockets: what we have Vacuum vessel, no Neon purification Cost of aluminum disks (raw material) Cost of quartz windows Reminder of the RICH schedule: Milestones: Design for mirror support: Vessel installation ready: Mirror and PM installation complete:

Photomultipliers 579 U03 good+best (batch ) 1210 U03 good (batch 2010) 155 U03 good (batch 2011) in order  Grand total: 1944 Other available PM (not all working) 3+12 U03 normal (batch ) 3+24 U06 good+best (batch ) Grand grand total: 1986 ( ) normal: 800 V > 1×10 5 good: 800 V > 5×10 5 best: 800 V > 1×10 6

HV divider E connectorized 137 not connectorized (8 of which used by GTK test beam) 8 from very first tests (to be checked if reusable) Grand total: 585 (+8), all with 0.45 m long cables To match 1986 pm: 1401 sockets missing ( ) Costs ( units):  68 €/pz (0.45 m cables) → K€ for 1401 units  77 €/pz (1.5 or 2.0 m cables) → K€ for 1401 units  84 €/pz (2.5 m cables)  89 €/pz (3.0 m cables) 600 € shipping cost, 9 months for full delivery. Today: choose cable length for 1400 socket. My proposal: 2.0 m See also Roberto’s talk

Vacuum vessel and gas system Today we should endorse:  The RICH vessel must be vacuum proof  The Gas system must be as simple as possible: after vacuum made inside the vessel, inject pure Neon  If vessel needs to be open, previous Neon injection gets lost, new filling to be done with fresh Neon See Piet’s talk

How to plug the disks with vacuum vessel Winston Cones & Quartz Hat PM + socket vacuum neon Valve open Valve closed air

Aluminum disks Aluminum 6082-T6 (anticorodal) 6.4 €/kg Sheet 800x800x40 mm3: 70.5 kg → € Sheet 800x800x30 mm3: 53.0 kg → € 2(Winston)+2(PM)+2(hat) sheets: € (+TVA) Pre-machining by external company: few KЄ (to be quantified) Drilling (Winston cones, PM holes, etc): Firenze worshop When finished, shipped at CERN for gluing quartz windows and mylar foils: agreement with Daniel Fraissard See Fernando’s talk

Quartz windows Praezisions Glas & Optik GmbH Windows made of UV-grade Quartz Glass: - double side polished - diameter. 12.7mm (+/-0,1) - thickness 1mm (+/-0,1) - ground edge, unbeveled Cost: 4,97 €/pz → 10 k€ for 2000 pieces (= k€) 4-6 working weeks delivery time

Conclusions The RICH is on the critical path for the 2012 techical run Main critical points:  vessel,  entry/exit windows,  beam pipe,  mirror support wall (and related gadgets) To be worked hardly but less critical:  PM, HV, DAQ, Mirrors Goal: have the RICH closed and filled with gas for 2012 tech run even with some temporary solutions, ready to take data

Mail from Ferdi Dear Massimo, I believe we all agree that the change to a vacuum proof RICH vessel is a good solution. In this case, we could officially endorse this design change in the forthcoming collaboration week. ( I saw that the fact is already anticipated in the report to the SPSC, which is very good, because we are anticipating the purchasing process with the same assumption). Regarding the time scale, we have launched this week a departmental request (DR) for the vessel, which is part of the obligatory purchasing procedure at CERN. The next steps will be a notification to the Finance Committee and a Market Survey. The Market Survey requires a simplified technical spec. and qualification criteria's for potential firms, and Piet is preparing this at the moment. Assuming things go fast the duration of the purchasing process will take about 20 weeks (from DR to contract signature), which would bring us to end of August. Hoping that the fabrication can be done in 6 months, we could hope to receive the vessel in March 2012, so that it can be installed before the summer. In an optimistic scenario we could hope to install during the summer 2012, the mirror support wall, mirrors, beam pipe and some PMT's, so that the RICH could be used with some channels in the Technical Run. But, this will require that the vessel time scale is respected and that all other items are pushed forward in parallel, which seems difficult. Discussing with Piet, we expect difficulties for the vessel planning and some shortcomings, in particular, for the Al windows and the beam pipe. Therefore, I suggest that we also consider some more modest scenarios as fall back solution: 1. For my part, I would give the vessel installation in spring 12 very high priority, in addition, I believe the RICH entry window should have equal priority because it is required to close the vacuum tank at the downstream end. But, one could think to stage the mirror support wall and the RICH exit window to after the 2012, if this reveals necessary. Meaning that -during the 2012 Run- the RICH vessel would stay open at the downstream end and can, of course not be filled with gas. In that case, the beam pipe connection between the upstream window and the LKR could be a temporary pipe connections in aluminium, or even, stainless steel. The installation would then be completed during 2013, when we have no beam. 2. As alternatives there could also be intermediate scenarios, e.g. re-using the former He tank window as RICH exit window, so that the vessel could be closed. But the interfacing to the RICH vessel and to the beam pipe is then not straight forward. At this stage, I am not proposing to change the official planning, but there might be caveats, and we should see how to deal with it. Let me have your reactions... Best regards, Ferdi

Dear Ferdi, during the next collaboration meeting we will endorse officially the "vacuum proof" solution for the RICH vessel and it is a good piece of news that the purchasing process has been started. I understand that the RICH vessel is on a critical path for the 2012 technical run and I fully agree with you that any effort must be done to have it in place in proper time. I will come back to vessel related "gadgets" (windows, pipe) in a moment but first let me address "my side". I have on my hands practically all the PMs (1950) and at the moment 600 PM sockets (HV dividers): the order about the remaining 1400 sockets was delayed for some details to be addressed (cable length) and money availability; now both are solved, cable length will be endorsed during the next meeting (long cable solution...) and money are available since few days so that the purchasing process will start and by spring 2012 we will have what we need. HV channels (mainframes and HV board) are all already on my hands; DAQ boards are under project finalization and production can be started when we prefer. I don't see bottle-necks in all the readout chain for the technical run (TEL62 is another issue but it is a general problem of the collaboration). All the RICH mirrors are ready and will be shipped at CERN in these days; I will pick up them during the next meeting for full testing of geometry and optical properties and later I will bring back them at CERN for coating. The mirror support system is a critical issue as we know: I hope that during the next meeting we can endorse the "single dowel approach". All the piezo-actuators are already on my hands. What is really on the critical path is the mirror support wall but I hope that having chosen the type of support we can converge on a project (we have already seen a preliminary stage prepared by Philippe) and proceed in parallel to the vessel (the mirror wall is responsibility of INFN). Of course some temporary approach or staging of the mirror alignment system can be envisaged for the technical run if the full approach will not be mature enough. Now back to mechanics: the PM disks are under design and will be presented at the next meeting; in my view we can start the raw material purchasing process after the meeting and all the machining (drilling...) which is INFN responsibility; the final preparation process (gluing of quartz windows and mylar foils) will be done at CERN. Also here I don't see major obstacles towards 2012 run. Now back to mechanics critical issue: if the vessel itself will be late there is nothing to discuss. So I assume the vessel in place for summer The critical points are really the entry and exit windows and the pipe. It is very good to give priority to the entry window in such a way to be able to close the vacuum decay region. I would recommend to fully consider temporary solution for the exit window (old helium tank window?) and the pipe (temporary new pipe or old helium tank pipe) in the vessel design. Finally the gas system: during the next meeting we can also endorse the simplified version we discussed about (injecting fresh neon after vacuum and nothing else); for the 2012 run we can consider filling normally (i.e. neon) but in extreme case (that I don't recommend) we can also take into account the possibility of a cheaper gas at much lower pressure (to be fully studied if possible). In summary: I strongly encourage to do any effort to have the RICH closed and filled with gas and ready to take data for the 2012 run even with some temporary solutions for some of the items quoted above. Greetings My answer to ferdi