Shielding of TOF I

1. Shielding ofTOF I history Decision to add a cage to the iron donut Feb07, CERN Only proven solution available at the time Now local shields are proven OK, at least for TOF II Confirmed at CM18 at RAL (TB) Jun07, CERN Exec drawings available Ghislain+Wing Summer 07 Request to TB (PRR & construction approval) 5 Sep 07 No reply yet ! Expensive quote at Fermilab Alan Early Oct 07 Discussed extensivey at CM19 PID, VP slides End Nov 07 Cheaper quote near Fermilab Alan V. Palladino TOF I shielding

2. Written opinions collected for this meeting 1) Bonesini Dear all in my understanding the baseline and EB endorsed option for TOF1 is the cage with brackets (the "expensive design"), any other low-cost option (such as the screw-on plate option) is not endorsed at the same level of a local shielding. The low cost option will imply probably not only the crane to pull up the second plate, but also the removal of the full TOF1 detector including uncabling and putting it on a service stall for any operation on PMTs. It is impossible (with the present frame design) to unscrew the PMTs of the first plane (no access from behind). In addition I am puzzled by heavy gang operation nearby a delicate detector. It seems as handling eggs nearby one ton of iron. My position is yes for the cage as it is now or eventually local shielding, no for the screw up/down low cost option. Cheers Maurizio ps regarding the local shielding my cost estimate was around 5K with some moderate increase of work for my mechanics workshop V. Palladino TOF I shielding

3. Written opinions collected for this meeting 2) Gregoire I • Dear all, • here are my comments about the shielding cage for TOF1. I am referring particularly to the simplified cage proposed by Alan • and to the comments made by Maurizio. • The construction of the whole cage could be divided into three categories according to their cost (raw material and machining): • the expensive parts (mainly labor-wise): the supporting brackets • the reasonable cost items : a) the Virostek plate, b) the closing flange, c) the split ring, d) the hinge mechanism • the inexpensive items: guide tubes, stoppers, plastic gliders, spacers, locking pins). • This division into three categories is partly based on my experience and on quotations I recently asked in Belgium (Louvain • workshop and commercial companies). From now on I shall neglect all items 3. V. Palladino TOF I shielding

4. Comments: A. Items 1 and 2A are absolutely mandatory for the operation of MICE and PID. Their fabrication should have started since months ... and specific quotations would have been asked much earlier. B. Items 2B,2C,2D and 3 could be replaced by a dedicated local shielding "à la TOF2" (... assuming an agreed design of TOF2 ! which is not yet the case up to now!). But this requires new evaluations, a new mechanical design, new QA/Audit procedure. It is not just a matter of scaling down the TOF2 case. In particular one should not cheat about the thickness of the required local iron shielding. C. Alan's proposal to make a simpler cage (no guide rails, cage opened by craning the closing flange ...). In the present design, it should be remembered that TOF1 is attached to the closing flange and ,as such, would be lifted with the closing flange. It would imply decabling the whole TOF1 which is not a really wise option. On the other hand and still with the present design, it is not complicated to attach TOF1 to the Virostek plate (thus avoiding decabling!). But then the split ring comes in the way, in the sense that it would be difficult to replace the PMTs located in the corners of the TOF1 setup, without dismounting the whole TOF1. Therefore, the practical way for implementing Alan's solution would be: - attach TOF1 on the Virostek plate, and - lift (as a single piece) the closing flange and the split ring. One then gets easy access to all parts of TOFI without decabling. This meets the wishes of Maurizio. - an advantage is that it completely avoids a specific support on the ground for TOF1 in an already crowded area. D. Budget-wise I do not think that Alan's solution makes lots of savings since the Virostek plate and supporting brackets already represent a very sizable fraction of the total cost. According to the preliminary quotes I got from Louvain, the hinge mechanism itself is not especially expensive compared to the rest. Vittorio already got a first overview of these quotes with other details. The closing flange should cost about 2 kEuros (including machining). I am rather confident that the total cost could be decreased to about 20 kEuros (30 k$) at most. But it is certainly better to share the construction among different manufacturers: commercial companies only for the two large items 1A and 2A, and lab/university workshops only for the more delicate and smaller parts 2A to 2D. Further transportation savings could be done if manufactured in the US. The initial quotes of 60 k$ by FNAL was ridiculous. E. Concluding remarks Considering the large amount of time lost (for various reasons!) since the completion of the whole design, and all the arguments I wrote above, I think it wiser to go ahead with the present cage design. The local shielding option for TOF1 would imply large delays (a couple of months) which are most probably not acceptable for MICE. Regards. Ghislain Written opinions collected for this meeting 2) Gregoire II V. Palladino TOF I shielding

5. Written opinions collected for this meeting 3) Lau V. Palladino TOF I shielding

6. Written opinions collected for this meeting 4) Bross V. Palladino TOF I shielding

7. On the basis of these opinions, debated in today’s PID ph meeting and the new quotes and informations collected the PID team recommends that to be agreed tomorrow V. Palladino TOF I shielding

8. The end The old remaining slides are left below as one or two may be rescued to illustrate better the motivations of the decision that we will take V. Palladino TOF I shielding

9. 5 Sep Dear Ken (and Alan),Ghislain completed his last checks and confirms Wing's opinion that the set of drawings athttp://www.physics.ox.ac.uk/design/MICE/Joe_TOFshielding_pdfdwgs/TOFshieldingdwgs_JT.htm are indeed ready for production.The PID group would like therefore to ask1) the TB to give the green light for its construction.2) Alan to inform us and the TB about the questions raised:a) is the tentative plan to have the TOFI cage built in or around Fermilab still viable?b) would it be ready (for mounting and field mapping, including fringes for TOFI) when the first solenoid arrives there from the Far West?c) if so, are the drawings of appropriate quality for the workshop he has in mind?We hope to hear soon from both of you. Best regardsVittorioReminder: were we to decide (soon) that a TOF II cage is also needed,the same drawings can be used with the sole modification of the inner radii.-------- Messaggio Originale --------Oggetto: decision process on TOF shielding cagesData: Wed, 13 Jun 2007 16:18:01 +0200 (CEST)Da: vittorio.palladino@na.infn.itA: Drumm, PV (Paul) <P.V.Drumm@rl.ac.uk>CC: Alain Blondel <alain.blondel@cern.ch>, Ghislain Gregoire<ghislain.gregoire@fynu.ucl.ac.be>, Michael S. Zisman<mszisman@lbl.gov>, tortora@roma3.infn.it, Maurizio Bonesini<maurizio.bonesini@mib.infn.it>, Alan Bross <bross@fnal.gov>Dear Paul,I have to miss today's TB, I will only be back Saturday, unfortunately.Ghislain can attend the meeting and report the following conclusionsfrom todays PID meeting:1) we ask the TB to approve constructon of a shielding cage for TOF I,complementing the shielding plate, based on the concepts reiterated inGhislain's slides today. As we have known for some time, they proveinequivocally the adequacy of the cage to guarantee appropriateperformance of the detector.Constructions drawings will be produced as soon as possible by Ghislainin collaboration with Wing and made available to Alan Bross to explorethe possibility of building the cage at Fermilab, where the solenoidwill stop on its way to RAL.Other labs eventually interested in the construction can also step up,now.2) it is the desire of the TOF II/KL team to postpone the decision onthe TOF II cage to next collaboration meeting, at the latest. Giventhe schedule of TOF II, this appears acceptable.Tests of PMTs in magnetic field in Milano will meanwhile complete theexploration of the possibility to do without a cage, using only localshieldings of TOF II PMTs.These tests already indicate that local shielding, in addition to theshielding plate, is sufficient for KL (and consequently SW).See you Saturday, when I hope to discuss this also in the EBCheers Vittorio V. Palladino TOF I shielding

10. 13 Sep Dear Tech Boarders,please find attached the note on the TOF I shielding cage that Ghislainwrote in record time. Concerning point 3 of the agenda.Concerning point 2 of the agenda, the TOF0-CKOV support stand, ourhope is to hear that a Production Readiness Review indeed is (or about to)taking place.I take the liberty to invite Maurizio, Lucien and Ghislain are invited to themeeting for these items, if there are no objectionsVittorio V. Palladino TOF I shielding

11. TOF0,CKOV TOFI, KL at RAL before Xmas due Jan 20 at RAL general picture • TOFI stand & shield undergoing Production Readiness Review shielding plate + global PMT niche (cage) PRR started …… first Fermilab quote sobering (60K$) … more quotes coming …. the fewer changes the better • CKOV+TOF0 stand is Production Ready …. green light for Wing to build it due Jan 15 at Fermilab • TOFII & beyond ……. final shield & layout being decided cage, expensive, less practical local PTM niches, attractive as more practical and cheaper TOFII at RAL Jun 08 • SW = back end of eμC AL finish its design & find the money SW at RAL uncertain V. Palladino TOF I shielding

12. MICE PID PMT shielding needs Large B fields at PMTs 4 Tesla An iron donut, the “Gregoire plate” then to become known as Virostek plate, drastically reduces the fields will be built in each solenoid V. Palladino TOF I shielding

13. Further PMT shielding neededhowever 1) “Gregoire cage” global shield 2) local heavy shields V. Palladino TOF I shielding

14. With Cage II Jan 08 B-mapped at FNAL Jan 15-Feb 15 including fringe fields Apr 08 B-mapped at FNAL Apr 15-May 15 including fringe fields Jul Jul 08 V. Palladino TOF I shielding

15. No Cage II Jan 08 B-mapped at FNAL Jan 15-Feb 15 including fringe fields Apr 08 B-mapped at FNAL Apr 15-May 15 including fringe fields Jul Jul 08 V. Palladino TOF I shielding

16. Second 90’ of PID session on Sunday GENERAL DOWNSTREAM LAYOUT G. Gregoire Shielding of TOF II & beyond: 3D calculation (15') M. Bonesini Decision process for shielding of TOF II & beyond (15') Discussion on downstream layout (10') V. Palladino TOF I shielding

17. Note to TB on Sep 14 Other file put on the web today V. Palladino TOF I shielding

18. Conclusion • We have two options • stick to the baseline and “pay for it” ….or for a cheaper version of it ….. Vittorio, At the PID meeting tomorrow can you bring up the following?  The current design of the TOF1 mag cage is expensive partly because of the mechanism that allows the TOF1 assembly to be slid out. A much cheaper approach would be to have the TOF1 cage simply be a ring with a cover plate and the proper supports to hold the TOF1 assembly. But there would be no mechanism to move it out sideways.  To access the TOF1, the cover plate would have to come off.  Ask Maurizio if he can do any foreseeable maintenance in this configuration.  Having to take off the cover plate is cumbersome and access may be an issue, but we should look into this approach. Still Trying. Thanks, Alan • cheaper may not imply downsizing ….. Mississipi would be great • Wing, Ghislain, Maurizio ready to focus on it • evaluate if the alternative of local shields can seriously be set up in time • Ghislain can let us know if local shields are good enough within few (2-6) weeks • if he gives some priority to this on KL • Maurizio tells us that he can do in time (mid April) with 5 to 10 thousands extra Euros • tohave the design adapted and the shields built & mounted on TOFI in magnetic contact with the upstream Virostek plate • Our recommendation is not to do anything that delays 1) V. Palladino TOF I shielding