E. BERTHOUMIEUX ON BEHALF THE N_TOF COLLABORATION 2011 n_TOF facility status Outlines Proton status Neutron beam line status Status of the 2010 gas release problem Status of the moderator & cooling circuit Remaining RP issues Foreseen / possible facility upgrade RP related Access related In the neutron beam line Web status DAQ update Proton status Reminder: proton is read by a new transformer since beginning of this year to solve the saturation problem For the 1 st time n_TOF reached is requested intensity in 2011: n_TOF Ph2 target received more beam than old one (> p) Neutron beam line status Reminder: First collimator not (and can not be) aligned. Small leakage at the filter station level (probably with the C filter) Several general electricity cuts occurred this year causing sometimes difficulties to restart the pumping, the magnet or the DAQ Sweeping magnet switched off due to a current balance alarm. No real causes found by the expert. EM & grounding problems in the WSTA. Fences have been replaced to avoid intrusion in the WSTA n_TOF inside ISR-8 n_TOF ventilation ~30 m 2 n_TOF cooling station ~70 m 2 Degassing duct (~60 m) Ventilation duct 2010 gas released problem (EDMS ) Maximum personnel exposure in 2010 due to the n_TOF cooling station External photon dose rate meas. Estimation of relative contribution of the skin and inhalation dose n_TOF operating conditions (beam and degassing) Occupation factor Modifications on moderator circuit (reminder) Cationic to mixed bed (previously saturated in enriched boron thanks to the bench test) resins. No raise in conductivity seen since the filling of the circuit Moderator circuit was not designed to switch twice a year from demineralized to borated water New expansion vessel to fill and check the water level in the moderator circuit New valves and pipes to empty the circuit. Filling/emptying only require now valves manipulations. Circuit was filled with enriched boric acid (not the same as last year!!!) the 1 st of march and boron (~1 kg) was added in the pot bore the 8 th of march Moderator station status Moderator circuit working at the saturation limit (filled with water containing 41.8 g/l of boric acid) Some difficulties to have a stable regime in the borated water circulation at start-up. Colder chilling water (72 C) and higher chilling water flow inside the pot bore to ensure that it remains the coolest point of the moderator circuit Conductivity very stable up to the end of run (~57 S) Since 23 nov 2011 conductivity raised to 62 S A water leakage (~1.5 l loss in 6 months) was found at the TT9 sensor position. Fixed but still under surveillance Very high tritium content (~17 MBq/l) Borated water will be replaced during this winter shutdown Cooling station status Shielding has been reinforced during 2010 shutdown Still not sufficient (see RP issues later) Leakage of the degassing circuit solved This circuit is now a radioactive source! Problem with the oxygen content measurement Value read by the station is wrong: shift of >0.04 mg/l compared to the value directly read on the apparatus. Threshold have been modified to take care of this shift. Action to be done during next shutdown to solve the problem RP issues (from J. Vollaire) Dose rate in the vicinity of the cooling station can be still above the CERN limit for a non exposed area Detector at the center Blocks added here Blocks added (31/08/2011) to overcome this issue 2 workplaces Center Right Remaining RP issues (from J. Vollaire) Before raw Sv/h Before norm. to alarm Sv/h After raw Sv/h After norm. to alarm Sv/h Reduction PMI FH40 (right) % FH40 (center) % Results are normalized to alarm A level on PMITOF03 (= 6 mSv/h alarm B = 7 mSv/h) Effect seems visible but is not sufficient to declassify the area with the current nominal intensity and alarm levels Summary of known problems in ISR8 Dose > 0.5 Sv/h Duct is a radioactive source Noise problem (not an n_TOF issue) Dose > 2.5 Sv/h RP related possible facility upgrade (ISR8) Remaining dose at workplace area assigned to skyshine effect. Dose in front of cooling station due to combination of skyshine effect and degassing duct. Foreseen/possible upgrades Permanent RP monitoring at workplace area (RP action already started) Send degassing duct directly to primary area The initial idea to just replace existing duct has been abandoned Roof (total or partial) over the station Simple FLUKA model (J. Vollaire) ShieldedUn-Shielded Roof : 5 cm steel Shielded case has lower side walls : 2 x 80 cm Conclusions Reduction of the dose rate from a factor in the TE workshop area Reduction of factor ~2 in front (second wall not in the simulation) due to opening Access system in primary area will be revised (EDMS , & ) PS complex access system will be completely revised during the long shutdown GS/ASE mandate will be focused on access only Ventilation of primary area will be part of the access system Cooling station will no longer be interlocked with beam!!! upgrades in the neutron beam line Filter station Solve the leakage problem Add/replace some filters? 1st collimator alignment? Magnet control (~30 years old, lack of spares pieces) Grounding improvement in WSTA EM decoupling of the beam pipe nearby the WSTA? Improve alignment in WSTA? n_TOF web status Old web site: pceet075.cern.ch No longer maintained: migration needed! TWiki website: cern.ch/ntof (default website) Need to register in TWiki group NtofGroup to access and modify some parts of the site DAQ website: ntofdaq.cern.ch Need CERN credentials + ntof-runs e-group membership Pictures gallery: ntofweb.cern.ch/gallery2 No longer maintained: moved to DAQ website Incoming public website: cern.ch/ntof-exp Need volonteers to build/transfer infos from old website n_TOF on indico: indico.cern.ch To be used for any n_TOF related meeting n_TOF section on CERN doc. server: cdsweb.cern.ch To publish any note/paper related to n_TOF A few word about DAQ Hardware Got 4 additional channels (DC282 module) from Zagreb Need to add memory inside Bought 4 2 nd hand DC282 modules (16 channels) Need to add another stream in the DAQ to be able to use it