Minutes from the ISOLDE Physics Group meeting on October 23, 2014
No comments on the minutes for the meetings of October 16th.
Technical news
HRS

•  During this year beams going through the HRS magnets were found to bent in non-predictable ways. Initially it was assumed to be due a mechanical misalignment.
  • o Recently it got worse to the point of not being able to extract the beam out of the magnets.
  • o It was finally found that the old electrostatic multipoles (decommissioned in 2000) had voltage on, probably due to software updates during LS1. They are now grounded and the power supplies are off.
• o These multipoles, not misalignment, seem to be responsible of the beam profile and transmission problems throughout the year,
•  Magnet cycling is still difficult. Sometimes it stops working and the software expert needs to be called to restart the software.
  • o Mass cycling time is around 12 minutes.
  • o No reproducibility problems have been found. The magnet can be cycled from lower or higher masses than the target.
•  The beam tuning through HRS magnets and the ISCOOL was realigned after the old multipoles had been turned off. Transmission between the final focus of the separator and after the ISCOOL is now 100%.
  • o No transmission was observed at the ISCOOL for a few hours on Wednesday. Found to be a small tuning problem after the old multipoles were turned off. Solved.
  • o EN recommends users to keep an eye on the tune to optimize the ISCOOL RFQ properties.
•  The separator slits lost their offset position, moving ‘0’ to a new position.
  • o The working set does not allow to input the full out position for the left slit.
  • o The slit motors have been temporarily disconnected in order to move them fully out manually.
  • o The expert has been called to fix the slits for the ISOLTRAP run on Friday.
•  The Faraday cups in front and behind the ISCOOL had a mechanical problem. Solved.
•  There have been reports of pressurized air tubes and valves breaking. A problem in the pressurized air system of the ISOLDE hall is suspected.

GPS

•  GPS physics run IS577 was extended until Wednesday morning, followed with yield tests using the tape station and IDS.
  • o Line and/or target heating tripped a few times during the run. The origin of these trips is not well understood yet.
•  After the blackout last Thursday evening the operators recovered the GPS and ISOLDE vacuum in 8 h. Target and PS Booster recovery was achieved in less than 24 h.
•  The automatic tuning system was used to tune to IDS at RC4.
  • o The automatic optimizer can tune any parameter of the beam line, including magnet parameters.
  • o Currently it cannot tune a full beam line. It needs a user defined sequence with a parameter space that it can handle. The sequence is run automatically
  • o The IS577 automatic tune showed beam oscillation on RC2-RC4 the scanners. This made for poor transmission to the IDS collimator.
  • o It is recommended to let the optimizer finish before trying manual fine tuning (even if it fails).
  • o ISOLTRAP, CRIS and VITO users offer to test the automatic tuner in their upcoming runs.
•  The molten salt target will be installed on Friday.

RILIS

•  All the pump lasers for dye lasers and the dye lasers themselves survived the power cut.

Safety

•  The west access fence for the tourniquet is not installed yet.
•  Please leave the SAS doors and the worksite fence closed, or close them if found open.
•  Please remind collaborators to not bring food to the ISOLDE hall.

ISOLTRAP measurement of Sc masses

•  The goal is to measure the mass of 50-53Sc isotopes.
  • o Never measured with high precision penning traps.
  • o Follow up of the 51-54Ca mass measurement in order to test the evolution of the N=32,34 closures for Z=20 nuclei.
  • o Yields are the main challenges..

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IS577 31Ar at IDS

•  The observed yield was 1-2 31Ar μC-1.
  • o The target was very stable, showing the same yields before and after the blackout.
  • o The 34Ar yield was calculated using the 666 keV gamma line both at the tape station and IDS. Both measurements agreed on 1.0(1)E5 ions/s using a 50 ms beamgate.

Building 508

•  The building will be received Wednesday October 29th.
•  Pending: Compressed air; control room cables; closed circuit water cooling system; internet.
•  A meeting with the main users of b508 to plan the installation of the different laboratories was held on Friday.
•  B275 needs to be clean up of all stored equipment after the move to B508. The space left for ISOLDE at B275 will be dedicated to workshops and labs.

AOB
The next meeting will take place at the same time Thursday next week (2pm, 30th October 2014).
Minutes taken by MMF