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Status of the n -TOF experiment

Status of the n -TOF experiment. E.Chiaveri ( EN-STI-EET ). ITEMS. n_TOF Facility Status Borated Water Moderator system Beam Alignment Ventilation System Integrated protons 2010 n_TOF-Ph2 experimental campaign 2011 ERINDA Program Summary. Entrance of n_TOF beam line.

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Status of the n -TOF experiment

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  1. Status of the n-TOF experiment E.Chiaveri(EN-STI-EET) n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  2. ITEMS n_TOF Collaboration Meeting Sevilla 15/17 December 2010 • n_TOF Facility Status • Borated Water Moderator system • Beam Alignment • Ventilation System • Integrated protons 2010 • n_TOF-Ph2 experimental campaign 2011 • ERINDA Program • Summary

  3. Entrance of n_TOF beam line n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  4. Entrance to the n_TOF beam line n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  5. Material entrance Changing room n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  6. n_TOF changing room n_TOF Changing room n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  7. Escape line n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  8. n_TOF Experimental Area n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  9. Cooling and moderator station • The target and moderator circuits are decoupled and work independently Moderator system Target cooling system n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  10. n_TOF borated water moderator circuit • The n_TOF borated water circuit is the result of a strong collaboration between different CERN groups: EN/STI, EN/CV, EN/MME and TE/VSC • Main goal: improvements of g background conditions in the 200 m experimental area due to a decrease in the production of thermal neutrons capture in 1H • a great improvement for neutron-induced capture reactions with the C6D6 liquid scintillator! • It is the first time that a borated water moderator is operated in saturated conditions (1.28% in H3BO3)  initial unknown parameters in the operation! n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  11. n_TOF borated water moderator circuit • October 2009: design specifications set • critical points: choice of materials and the technical implementation of the solution envisaged to keep the boric acid concentration in a stable condition • April 2010: the system has been installed, connected with the cooling circuit and tested successfully with light water. • May 2010: the system was tested successfully with beam • May-June 2010: commissioning of the new beam line and of the moderator circuit: • reduction of thermal peak as expected from simulations • observation of the expected reduction in the background due to delayed g-rays reaching the EAR together with ~keV neutrons Complex work realized in only 6 months! n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  12. n_TOF borated water moderator circuit • Chemical stability is an asset for the safe operation of the cooling and moderator circuit • An increase of the water conductivity was observed during operation • regular water samples analysis showed no worries for corrosion, since conductivity was due to the presence of non-reacting sodium • Sodium was originating from the non optimized cationic resin used to filter activation products • A test bench will be realized at CERN in November 2010 in view of the 2011 n_TOF run • 2011 n_TOF run will operate with an optimized resin and looks forward to a successful run n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  13. The neutron fluence with normal and borated water (100 bpd) x18 x13 x1.6 x1.2 *Flux from PTB chamber, to be combined with MGAS, SiMon and simulations (FLUKA and MCNP). n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  14. n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  15. Test bench for n_TOF resins (moderator circuit) • 2010 run showed an unexpected increase of conductivity in the moderator circuit, mainly due to the release of Na from the non-specialized resins (Amberlite 200C Na – cationic only) • A test bench was setup from 22nd November 2010 @CERN to study the effectiveness of a nuclear-grade mixed bed resin (IRN 9882LN) foreseen for 2011 operation • Objectives: • follow the evolution of the conductivity as function of time (wash-out of resins) • quantify the boric acid retention by the mixed bed before reaching equilibrium • Preliminary results: • Conductivity evolution present but much lower (as expected, 4x reduction wrt cationic, after recirculation in resin) • H3BO3 retention: ~150 g/l  ~4 kg needed for saturation vessel Al vessel resin Recirculation pump L. Ferreira, R. Mollay + EN/STI n_TOF Collaboration Meeting Sevilla 15/17 December 2010 MC

  16. Alignment campaign 2010 • Surveyor’s theoretical beam line defined with the following steps: • A theodolite is placed in the Escape Lane (FIC2 place), where fixed (2001) reference points are placed in the floor • Theodolite view is set to 0.67°proper inclination of the TOF line. For the radial direction, uses a reference in the EL • Observation: The center of the theodolite is very close to the mechanical center of the neutron window • Vertical ok • Horizontal is shifted by ~1 cm n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  17. Alignment campaign 2010 • The 1st collimator is shifted up by 1.9 cm, left by 0.75 cm, looking to the target • No information on the possible tilt • Explains the 2009 movements on the 2nd collimator • ~9% decrease in fluence from the simulations • Movement possible but not easy (not foreseen for now) • NB: this shift was always in place, since the construction of the facility! • 2010 Alignment will be performed by looking: • Vertically mechanical center of the window • Radially  5 cm to the leftof the mechanical center • New reference points will be established in the EAR-WS n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  18. Plans for 2010 concerning alignment • First measurements will include the movement of the 2nd collimatorto try maximizing the fluence • vertical movement only • horizontal will be available but too risky for the moment (possible if beam profile will show a significant horizontal skew) • SiMon + XYMG with 10B or 235U sample • simultaneous profile and fluence variation evaluation • borated water (*) • 235U will allow to have a reasonable statistics in the HE part • XYMG current routine (v. 2.8) limited by a significant dead-time (signal is ~200 ms long) X-Y MicroMegas Silicon Monitor Monitoring MGAS n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  19. Alignment Summary • n_TOF beam line up to the Experimental Area is aligned by looking at the spallation target neutron window • 2nd collimator is aligned accordingly • 1st collimator is shifted/tilted, no easy way to move it back to proper position  its effect on the flux reduction account to few % • Good agreement with simulated beam profile • Indications on the misalignment of the 2nd collimator • Predictions have been verified experimentally  could be used for alignment purposes n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  20. Ventilation system • By request of RP, the target area is continuously flushed out and air is released in the atmosphere on top of a building in ISR area: • Filter: 7Be, not efficient for noble gases • Flush: ~500 m3/h (after sealing of the primary area –40 Pa according to ISO 17873) • Volume: 1200 m3 • Dose to public: < 1mSv (!!) for 1.6*1019 p • assumed 41Ar (75%), 11C, 13N release n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  21. Releases from n_TOF during the 2009 run • In correspondence of each degassing operation, large short-lived radioactive release from the ventilation stack  triggers alarms within CERN perimeter Before intervention After intervention O2 limit – 0.08 mg/l 0.2 mg/l x 20 reduction! “baseline” due to target area activation + on top degassing releases (up to 1.5 GBq) … almost only target area activation n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  22. n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  23. Beam sharing in 2010 • Total beam intensity: 24% higher than initially scheduled • Beam usage efficiency for physics: ~85% n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  24. Parallel Plate Avalanche Chamber (PPAC) Detector into n_TOF Experimental Area • The installation of PPAC has been successfully done in five days taking into account • transport, vacuum, alignment, gas connection. • This time should be considered for the future planning. n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  25. n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  26. Parallel Plate Avalanche Chamber (PPAC) Detector n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  27. Parallel Plate Avalanche Chamber (PPAC) Detector into n_TOF Experimental Area n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  28. n_TOF-Ph2 experimental campaign 2011 n_TOF Collaboration Meeting Sevilla 15/17 December 2010 • After negotiation with the top management the Research Board accept to start nTOF run in March concurrently with the CNGS extension instead of May!! •   It was agreed that during this period the proton delivery to n-ToF should be based on around 6 cycles per supercycle. •  Once the other facilities are started up the delivery of dedicated cycles to n-ToF can then be reduced (from 4 to 3 daytime) in order to increase the duty cycle to Isolde. •   By this means it should be possible to achieve 1.6x10+19 pot for n-ToF.

  29. Status of proposed experiments Approved by INTC New *To be studied in more detail + Possibility of measuring in parallel with 240,242Pu(n,f) n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  30. ERINDAEuropean Research Infrastructuresfor Nuclear Data Applications • Objective: • contribute significantly to the future nuclear data needs for • radioactive waste management and innovative GenIV nuclear reactor systems • create access and beam-time for nuclear data measurements at EU facilities • direct this beam-time towards requests of highest priority and scientific value n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  31. ERINDA draft proposal EFNUDAT partners CNRS/IN2P3 (Bordeaux and Orsay, France) JRC-IRMM (Geel, Belgium) IKI (Budapest, Hungary) FZD (Dresden, Germany) PTB (Braunschweig, Germany) UU-TSL (Uppsala, Sweden) CEA (Bruyères-le-Châtel, France) n_TOF (Genève, Switzerland) NPI (Rez, Czech Republic) new partners NPL (Teddington, UK) IFIN-HH (Bucharest, Romania) JYU (Jyväskylä, Finland) JSI (Ljubljana, Slovenia) TSCS Charles Univ. (Rez, Czech Republic) potential (future) partners NFS (Caen, France) FRANZ (Frankfurt, Germany) n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  32. n_TOF Collaboration Meeting Sevilla 15/17 December 2010

  33. n_TOF Experiment Summary • Work Sector Type A experimental area • Converted the actual experimental area to a Work Sector Type A  no major restrictions on radioactive samples measurement • Significant improvement in measurement capabilities • 2. Operation of a borated water moderation system • 3. Disposal of the old Target and Radioactive Sources • Old Radioactive Sources delivered to ( National Technical University of Athens • IRMM-Geel, Forschungszentrum Dresden-Rossendorf (FZD)) • Disposal of Old target and remaining Sources under discussion with PSI • 4. 2009/2010 experimental campaign : • Most of the program completed and analysis ongoing • 5. 20011/2015 perspectives: • New institutes involved in the MoU (Mancheter, York,OakRidge,Thessaloniki ….) • 14 PhD at present n_TOF Collaboration Meeting Sevilla 15/17 December 2010

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