IV. KATRIN Collaboration Meeting: 2 June X-VAT Workshop (Summary) - XL Spectrometer Design Status (Vacuum, WG report)

Transcription

1 IV. KATRIN Collaboration Meeting: 2 June 2003 X-VAT Workshop (Summary) - XL Spectrometer Design Status (Vacuum, WG report) Chris Day

2 X-VAT Workshop - Its Charge Recommendation by the International Review Panel (May 2002): the panel believes that.. the desired low pressure is probably achievable, although certainly non-trivial. The planned workshop involving UHV experts from different areas is considered an important step in this direction.. IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 2 of 12

3 X-VAT Workshop Its Objectives The Workshop was performed to. Address the vacuum technological and operational challenges,. learn and benefit from the expertise from others,. develop specific recommendations referring to the KATRIN vacuum case,. obtain the approval of plausibility of our concept within the vacuum community,. present the KATRIN project to the outside world,. establish further collaboration and strengthening links to the vacuum community, discuss the possibility of a proposal within FP6 and to identify partners IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 3 of 12

4 X-VAT Workshop - Its Performance - 50 participants (maximum limit) from 10 countries. (9 KATRIN members). - A good mixture of academia (20%), research centers (45%), and industry (35%) invited plenary talks by distinguished vacuum experts. The convenors want to thank all those who have helped them in organising a successful workshop! IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 4 of 12

5 X-VAT Workshop Its Results New promising collaborations started/under consideration (ASTEC, Daresbury, UK; Jefferson Lab, USA; ) Additional input to the group of VELASTAR Partners Assessment of the KATRIN vacuum case: A) The differential pumping system (sound design! Final assessment with MC study Talk by B. Bornschein on the reference design, Tuesday evening) B) The cryosection (more design efforts needed, Ar frost vs. carbon?, cryogenic peripheral systems for Ar more complicated than for carbon, no relevant data existing about pressures < mbar tritium for a cryosorption pump, experimental work required as design input Experiments planned at TLK (Oleg Kazachenko et al. ) C) The main spectrometer (several open questions VELASTAR proposal, Talk by M. Noe ) All talks can be downloaded from the KATRIN home page: IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 5 of 12

6 The XL Spectrometer Working Group - Its Charge Decision of the last KATRIN Collaboration Board Meeting in Mainz, December 2002:.. to go for the 10 m main spectrometer version!. PiP Picture by GD IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 6 of 12

7 The XL Spectrometer Working Group - Requirements (EM) Design example ( to follow neatly the contour of the magnetic flux) Reference size parameters given by the electromagnetic design (outlined in the Talk by A. Osipowicz) m inner vessel diameter. (9.50 m flux tube diameter m length (minimum) Volume about 1500 m³ Inner surface about 850 m² Weight about 200 tons (not necessarily , as µ(overall)<1.1 is sufficient) (depending on final design) IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 7 of 12

8 The XL Spectrometer Working Group - Requirements (Vacuum) The installed pumping speed S has to be balanced against the existing gas flows Q(total)=Q(inflow)+Q(leak)+Q(outgassing wall)+q(outgassing, installation); S=Q(total)/p Assuming no gas (Q(inflow)<10-11 (mbar l)/s) coming from upstream due to an effective cryosection. Assuming negligible integral leak rate (Q(leak)=10-8 (mbar l)/s Hoping for negligible outgassing rate of the interior parts (electrodes + detector)? Thus, the dominant gas source is the outgassing rate of the walls: Q(total) Q(outgassing)=q Surface Confirmed minimum outgassing rate for UHV systems of conventional size: q=10-13 (mbar l/s cm²) However, a value which may be guaranteed by a company is only (mbar l/s cm²) Available expertise is from thin-walled systems and extrapolation to thick-walled systems is doubtful. As challenging requirement: (mbar l/s cm²) is our reference outgassing rate for our huge system! (This is predominantly hydrogen) Combined with the reference pressure of mbar and referred to the inner surface, this corresponds to a gas flow of Q(total)=10-5 (mbar l)/s, and a pumping speed required of S=1000 m³/s. Real case: The outgassing decreases with time t (according to t -n ; n=0.5.1); but at the same time, it may rise due to deterioration of the surface during mounting of the electrode system. Additional effect on top: Exploit the temperature dependence of outgassing according to Sieverts s law - decrease by one decade due to cooling down from ambient to 20 C. There has been shown some experimental evidence for this gain on the scale of the test cylinder experiments (See talk by Lutz Bornschein) IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 8 of 12

9 The XL Spectrometer Working Group - Provision of Pumping Speed Based on getter pumping (NEG) Discussed at X-VAT A External pumping: Scale up of the approach chosen. for the pre-spectrometer; As being in free molecular flow regime --> the pumping speed is limited by the entrance crosssection of the connecting flange. B Internal pumping: Allows for 100% exploitation of the. intrinsic getter strip pumping speed. Length related pumping speed is about 0.8 m³/s per meter strip length (optimum) --> several km of strips. C Via surface coating Option B is chosen as reference approach IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 9 of 12

10 The XL Spectrometer Working Group - Alternative Design Approaches Alternative : effective Q (outgassing) 0 (beyond the superperfect surface treatment) Alternative 1: Close the outgassing surface by surface coating (The CERN approach). However, no technology available to perform this coating; experience exists only for small scale applications; success requires very good homogeneity of the coated layer. The discussion on X-VAT on this topic was quite controversial; opinions going from from being reluctant (CERN, ESRF) to recommending to go for this way (LEYBOLD). We decided not to make this part of the reference design, but to incorporate this in the VELASTAR proposal, as being a real adventure project (see talk by Matthias Noe) Alternative 2 (raised in X-VAT): Cool down the main spectrometer vessel to 77 K. Alternative 3 (raised in X-VAT): Combination of cryopumps and thin-walled design (for which expertise is available) by a vessel-in-vessel approach. IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 10 of 12

11 The XL Spectrometer Working Group - Manufacturing Options As discussed in the last Collaboration Meeting: The one proposal put forward at the X-VAT workshop was in line with the large pieces solution: IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 11 of 12

12 Conclusions and Outlook 1. The X-VAT workshop produced significant input information to further refine the vacuum design issues. KATRIN is now known in the vacuum community and links will be strengthened. The different vacuum approaches could be classified: A more conservative reference design was elaborated, which is believed to work. The more risky ideas, which are promising but not yet demonstrated to work, will be dealt within the frame of the VELASTAR proposal. The KATRIN vacuum case will be presented at the ASEVA Vacuum Gas Dynamics Workshop to obtain guidelines for flow modelling starting from the source down to the spectrometers. 2. The set of reference parameter numbers will be used to contact candidate manufacturing companies. 3. With respect to the current KATRIN project plan, this enterprise is in time: Define design requirements 4/03-7/03 Design proposal, design study 7/03-10/03 Tender action and ordering 11/03-5/04 Manufacturing 5/04-6/05 IV KATRIN Collaboration Meeting, Rez, 2 June 2003 CD, Page 12 of 12

13 Participant List Name Affiliation address Baeßler, Stefan University Mainz, D Stefan.baessler@uni-mainz.de Inst. für Physik Barday, Roman University Mainz, D Romanb@kph.uni-mainz.de Inst. für Kernphysik Blanchard, Sylvain SDMS, Saint-Romans F Blanchard@sdms.fr Boissin, Vacuum consultant F Boissin938@aol.com Jean-Claude Bonmassar, Luca Varian Vacuum I Luca.bonmassar@varianinc.com Technologies, Torino Bonn, Jochen University Mainz, D Jochen.bonn@uni-mainz.de Inst. für Physik Bornschein, Lutz University Karlsruhe, D Lutz.bornschein@ik.fzk.de Inst. für Exp. Kernphysik Blümer, Johannes Forschungszentrum and University Karlsruhe D Johannes.bluemer@ik.fzk.de Brinkmann, Harald Leybold Vakuum GmbH D Harald.brinkmann@leyboldvakuum.com Chuntonov, Konstantin Technologies, AT konstantin.chuntonov@at.flextronics.com Konstantin Klagenfurt, Day, Christian Forschungszentrum D Christian.day@itp.fzk.de Karlsruhe (FZK), Inst. Techn. Physik (ITP) Dremel, Matthias FZK-ITP D Matthias.dremel@itp.fzk.de Drexlin, Guido FZK, Inst. für Kernphysik D Guido.drexlin@ik.fzk.de (IK) Fabrie, Frank Varian Deutschland D Frank.fabrie@varianinc.com GmbH, Darmstadt Fierlinger, Peter PSI Villigen CH Peter.fierlinger@psi.ch Hauer, Volker FZK-ITP D Volker.hauer@itp.fzk.de Herz, Werner FZK-ITP D Werner.herz@itp.fzk.de Henneck, Reinhold PSI Villigen CH henneck@psi.ch Hilleret, Noel CERN-LHC-VAC CH Noel.hilleret@cern.ch Horn, Ronny PINK GmbH D rhorn@pink.de Hseuh, Hsiao- Chaun RHIC, Brookhaven National Lab USA hseuh@bnl.gov Kersevan, Roberto ESRF, Grenoble F kersevan@esrf.fr Kurdul, Jörg GSI Darmstadt D j.kurdul@gsi.de Leher, Franz DWE GmbH D Franz.leher@dwe.de Luo, Xueli University Heidelberg, D luo@phys.uni-heidelberg.de Physik. Institut Meisel, Gert FZK-IK D Gert.meisel@ik.fzk.de Müller, Beatrix University Bonn, Inst. für D mueller@iskp.uni-bonn.de Strahlen- und Kernphysik Müller, Dieter Leybold Vakuum GmbH D Dieter.mueller@leyboldvakuum.com

14 Müller, Norbert Inficon, Balzers LI Myneni, Ganapati Rao Jefferson Lab, SRF USA Nemanic, Vincenc Jozef Stefan Institute, SI Ljubljana, Noe, Mathias FZK-ITP D Mathias.noe@itp.fzk.de Otten, Ernst- University Mainz, D Ernst.otten@uni-mainz.de Wilhelm Physik. Institut Paetz, Stephan SAES Getters, Köln D Stephan_paetz@saes-group.com Pichlmaier, Axel PSI Villigen CH Axel.pichlmaier@psi.ch Rauch, Michael PINK GmbH D mrauch@pink.de Reich-Sprenger, GSI Darmstadt D h.reich@gsi.de Hartmut Reid, Ron CCLRC Daresbury Lab UK r.j.reid@dl.ac.uk Saksagansky, Georgy D.V. Efremov Institute, St Petersburg, RUS RUS gruss@niiefa.spb.su Sauge, Xavier SDMS, Saint-Romans F sauge@sdms.fr Schulz, Lothar PSI Villigen CH Lothar.schulz@psi.ch Sostmann, Giselher Varian Deutschland GmbH, Darmstadt D Giselher.sostmann@varianinc.com Stenitzer, Thomas Konstantin Technologies, AT office@konstantin.-technologies.com Klagenfurt Völker, Andreas FZK-ISS (ANKA) D voelker@iss.fzk.de Voss, Gerhard Leybold Vakuum GmbH D Gerhard.voss@leyboldvakuum.com Wolf, Joachim University Karlsruhe, D Joachim.wolf@ik.fzk.de IEKP Zapfe, Kirsten DESY-MVP, Hamburg D Kirsten.zapfe@desy.de

15 Workshop Photo Thanks to all the participants for this very fruitful meeting!