Minutes from the ISOLDE Physics Group meeting on August 12th, 2015
No comments to the minutes of the PG meeting held last week.
Technical news
- GPS:
- Extraction electrode did not fully retract during the last decoupling operation.
- The compressed air motor that moves the spindle system retracting the electrode was observed rotating.
- The two coupled spindles could not be observed with the telemax because of complicated angles. If they are gripped they will need to be replaced. To be investigasted.
- The GPS front end was accidentally vented during one of the sample changes. The target was not damaged.
- The coordinator warns that the GPS target heating adds 300 A to the user-specified value. Users should be carefull to not apply current over the maximum allowed value, before the problem is solved.
- HRS:
- The piston driving the target shutter/target valve did not move when given instructions to shut off the target.
- The compressed air tubes had been disconnected. Reconnecting did not fix the problem.
- Using the telemax remote robot the shutter/valve were lowered to the closed position, but not to the fully sealed position.
- After the target was closed it was removed in order to be able to install the target for COLLAPS physics.
- RILIS:
- Both pump lasers of the dye lasers broke at the end of the Cd campaing. The dysprosium->terbium collections were done with an alternative scheme usin TiSa lasers.
- One of the pumps lasers died when connected to UPS, the other from unkown reasons. An investigation of the quality of electrical power in the hall will be launched.
- Beam diagnostics:
- The intervention to replace the diagnostic boxes at CC0 and RC2 have been postponed. The CC0 box will be replaced next Tuesday, RC2 before the end of the month.
- The ISODLE leak detector has been repaired and shipped to CERN.
- Thanks to ISOLDE users and locals cleaning the ISOLDE hall extension and of the common area of B275 were cleaned in two interventions.
Safety
- The coordinator remind that the door accessing the laboratories in the ground floor of B508 should be permanently closed. A electronic lock with the dosimeter reader will be installed in the near future.
- The chemical cabinet is now located closer to the control room, in the area next to the cabinets for storage of radioactive parts.
Dysprosium->terbium collections at GLM
- All five shipments of 149Tb to PSI were done as planned, the chemistry and labeling worked well and the activity could be used for cell studies and mouse experiments. All mice could be treated as planned, now the longtime observation starts. In addition 152Tb was shipped and successfully used for PET imaging. Finally, 152Tb was transported to Lausanne (arriving this morning) after chemical purification.
- Also 134Ce, 140Nd, 165Tm and 169Yb were collected and shipped to Hevesy Lab. Experiments are now under way.
- MR-TOF was extremely useful to quickly assess the beam composition and to understand its dependance on target and line heating and laser power. We found as optimum operation point in terms of Tb/CeO ratio with a reduced power (10-15W) of the green laser and a reduced line heating (about 280A). Unfortunately the practical implementation for a long collection remains pending as glitches of the line current control affected the planning of the nights.
- The new TiSa based RILIS scheme gave at least the same efficiency as the previous one with dye lasers and the RILIS operation was very stable.
- The 6um/25um target gave better 149Tb yields than last year's 25/25um one, probably due to reduced decay losses of 149Dy. Qualitatively it seems the target got "slower" (ion currents fluctuating a bit less upon proton impact) over the weekend, maybe some of the foils started to sinter together?].
- As usual the yields dropped over the week of use but at the end of the run the target was still usable.
- All packing of the radioactive parcels and all the radioactive shipments went very smoothly, even despite some EDH bugs.
AOB
-Elisa Rapisarda has stepped down of the future coordinator position after receiving an offer at PSI. The new coordinator will be Karl Johnston.
-The next meeting will take place on Wednesday next week (19th August 2015) followed by a presentation by ISOLDE summer students and a seminar to be announced.
Minutes taken by MMF