Minutes from the ISOLDE Physics Group meeting on September 18, 2014
No comments to the minutes from the ISOLDE Physics Group Meeting on September 11, 2014.
IS525 Study of multi-neutron emission in the beta-decay of 11Li
• The experiment measures neutron energy using the time-of-flight technique. This requires lots of detectors 1 m away from the implantation point. The experiment thus takes lots of space, check with them if they interfere other experiments
• Local contacts are Miguel Madurga and Morten Lund
• Participants from France and Spain lead by Franck Delaunay, Nigel Orr, Daniel Cano, and Trino Martinez come next week. Please help them to work in safe conditions and if needed – remind them the CERN rules.
Technical news
GPS
• Solid state physics collections run with the UCx + neutron converter + RILIS target (protons on target to produce Mn and In) were completed.
o One extra night was given to IDS to check for Mn yields. Surface collections with rubidium and at the GLM by Portuguese group followed.
o The heating and HV dropped seven times during these runs. Experience from 2012 pointed to the HV ramping cards, but it is still being investigated.
• The GPS high voltage broke completely during the run, caused by a faulty modulator. The part has been exchanged already.
• A new target (Sn + plasma) for solid state collections was installed on Wednesday afternoon. The clamping system was checked on Thursday morning to investigate the tripping problems associated with it.
• Proton scan and yield test for the new target scheduled for Friday.
• FC490 Faraday cup at GPS and scanner have started showing large fluctuations (on pA scale), even with no beam. EN are following the problem.
HRS
• Physics run started with proton scan on Friday. Yield tests were not completed due to lack of time. The observed proton scan profile was broad (info after meeting: this is only due to diagnostics problem) so the protons were left in (0,0) position.
• The HRS magnet had big problems with cycling. The manual developed to instruct users how to fix the magnets turned out not to work in many cases.
o On Saturday, Pascal found a hardware workaround power cycling the computers and resetting the tesla meters.
o On Sunday this workaround stopped working, so Pascal taught users to change the magnets manually (using the software to calculate the desired magnetic fields). This is difficult for users as is they need to take into account the magnet hysteresis. Users indicate this problem did not affect yields.
o The communications box for the HRS magnets was changed on Monday, following Pascal’s suspicion that this is the reason of most problems. Users report that magnet cycling is back to the normal 12 min since then.
o The Fellow that designed the new cycling software is being re-employed from beginning of October. He will look into the long cycling time problem.
• Tim Giles has investigated the transmission through the separator and cooler following reports from users of low transmission rates (60% through magnets and 60% of that to central beamline).
o When the typical tune prior LS1 is used the beam does not go through nicely. He suspects the magnets might be misaligned. It will be investigated during the winter shutdown.
o Using the new automatic tuner developed by Tim’s student they could achieve 80% transmission through the magnets.
o Some time ago ISOLTRAP reported that HRS beam emittance coming from the ISCOOL in transmission mode seemed to be worse than expected (much longer cooling times needed in ISOLTRAPS cooler). Tim is going to investigate the cooler. Frank mentions that the problem could also be due to a slow or leaky beam gate ramp up. To be followed.
• Target change for CRIS, ISOLTRAP, and Windmill scheduled for Monday, UCx surface ion source. Physics is expected to start Thursday.
• When using HRS users are only allowed to change the ISCOOL RF frequency (when changing masses). All other parameters should be kept constant.
Safety
• GRAMS radiation alarms went off during beam transport from GPS for ISOLTRAP and IDS.
o ISOLTRAP alarms were understood to be triggered when radioactive beam was measured in the CC0 FC.
o IDS alarms were set off by the 133Ba isomer coming with the 133Cs beam used for tuning. It was collected at the IDS Faraday cup in front of the implantation point.
• Users and locals should remember to be especially careful when taking stable beam from an irradiated target – such stable beam is often contaminated with long-lived isobars. Using lighter nuclei always helps.
• Locals should update Magda with the requested information concerning GLIMOS persons for fixed setups and on the courses they had followed.
o A new electrical course for ISOLDE physicists is being discussed as part of the required electrical habilitation. Magda is following it up.
• Experimental safety for external users should be monitored and ensured by the local contacts. If you see unsafe behavior, please address the involved persons.
• The tourniquet access has been installed in the ISOLDE users’ entrance. It still requires installing batteries and a fence.
• The fence separating the ISOLDE worksite from the ISOLDE experimental area has been restored. A chain and lock have been installed, with they key hanging next to the lock. Experimenters are reminded to always lock the gate after moving equipment through.
• Users make a formal complaint on having hats belonging to experiments moved in to the common pools and worn by other people. All hats should be stored in the common pools and experimenters should avoid using hats belonging to others.
Miscellanea
• Building 508 is progressing towards completion. Furniture in the laboratories has to be organized by users (bought or taken from recuperation).
o There will be a meeting regarding the move into the laboratories when Monika is back at ISOLDE.
o About 300 cables have been requested between b508 and ISOLDE, connected to different patch panels in both building (including the ISOLDE control room). Magda says that many cables are needed for the new control room, but comments from Erwin and Richard Catherall are missing.
o Cooling water closed circuit is still under design. Users provided a range of temperatures they need and a final single temperature remains to be chosen by the designer. The chiller size is inversely proportional to the desired temperature, and there are not enough funds to buy it yet.
o The closed circuit water pipes will be installed this year, the chiller most likely next year.
• Once B508 is finished and the labs are moved back from B275, the situation of the latter needs to be revisited.
o It seems that B275 cannot be used for long storage anymore and all the space needs to be repurposed for labs.
o Long storage space should be available at CERN, but lab space in B275 should be kept as free of clutter as possible.
• Maria reminds the group to finish printing and installing the permanent-experiment posters.
• A question is raised on the current custodian of the ISOLDE electronics pool and acquisition. All request on the electronics pool should be addressed to Miguel Madurga
• Maria Borge volunteers to be TSO for B275.
• The last summer student presentation will be held after the meeting Wednesday next week. The week after that it’ll be Claes Fahlander.
IDS IS590
• A used and new UC target, both with neutron converters were tested for Mn production. Both targets have substantially lower yields, factor of 20, than 2009 run.
• The used target was found to have a factor 2-3 less production than expected, not enough to explain the lack of 68Mn production.
• A large isotope shift causing lower Mn yields was mentioned as a possible cause of lower yield. After verification with RILIS this info turned out not to be fully correct. A reduction of a maximum of a factor of 2 could be attributed to the laser frequency tuning.
Windmill & ISOLTRAP
• All At isotopes between A=194 to 217 have been scanned, except for microsecond-lived species.
• The program is on track to measure all species by the end of the beam time, with the possibility of extending it to neutron rich if time permits.
• Alpha decay was studied at the Windmill looking for alpha fine structure (decay to excited states); identification and mass were performed at the MR-TOF spectrometer at ISOLTRAP.
• Maria comments that a MR-TOF after the ISCOOL to purify beams further would be a nice addition to the ISOLDE facility.
The next meeting will take place at the same time Wednesday next week (2pm, 1st October 2014)
Minutes taken by MMF