Minutes from the ISOLDE Physics Group Meeting September 4, 2014
Comments to the minutes from the ISOLDE Physics Group Meeting from August 21, 2014:
- ISOLTRAP run description should be rephrased to: The team performed about 50% of the program in much less than the allocated beam time in spite of the technical problems at ISOLDE, however, not reaching the envisaged statistical uncertainty. Mass measurements were done on 129Cd, 130Cd and 131Cd isotopes. The team reported longer cooling times needed to capture the ISOLDE beam from HRS as compared to GPS beam which might result from a different energy profile or emittance of the HRS beam.
TECHNICAL NEWS:
GPS:
- Hg beams delivered from Pb target Hg until Monday morning 8am.
- Good runs were reported for the experiments on LA1, GLM and IDS.
- New target, UC2-C with neutron converter was installed on Tuesday, September 2. After initial tests several sparks and voltage tripping was reported when operating with 60 keV. Therefore, the target voltage was set on 50 keV.
- A few problems with the robot gripper were encountered during the operation of the target exchange. These were temporarily repaired and will have to be modified during the next shut-down.
HRS:
- Last week many meetings were dedicated to the issues with the magnet controls. The specialists agreed to wait until the winter shut-down for more detailed investigations of the observed problems.
- Once trying to reproduce the problem of cycling the magnet in presence of a specialist no problem has occurred. Therefore, users are asked to call the specialist immediately when the symptoms reappear again.
- The cycling of the magnet takes currently around 10 min and it will not be improved before the next shut-down.
- Several problems were reported with the RFQ Cooler. The biggest one concerns the base frequency of the amplifier which is not the same as previously. Therefore, the use of old settings is no longer valid. Furthermore, a significant change in frequency will have basically no influence on the beam characteristics.
Other:
- It has been reported that an improvement of the beam quality can be obtained by moving the extraction electrode on both separators. The current offset is at 75 mm but it has been pointed out that this is not always the best positions. Optimization of that value should be done as a part of the separator set-up.
- Several problems with the vacuum system for REXEBIS have been encountered and are now being followed up. REXTRAP is operational.
- The RILIS team intervention on the laser window on the HRS 90° magnet went smoothly on August 28. Also, the team reported on the recent tests on Hg ionization done on the UC2 target last week.
Physics:
- Mn beamtime has been under question due to many problems with the UC2 target with the neutron converter. Very low yields were reported by all the teams stopping them from performing the experiments. The OP and target teams are following on that. No physics has been done yet.
Safety:
- A positive feedback was reported on the RP hands-on course made for ISOLDE.
- Clean-ups of the bld. 179 and 275 have been advised by RP.
- New procedures have been implemented for collections and sample transfer to bld. 275. Since 275 is not classified as class C lab the maximum doses have to be less than 1LA. For the transport, the dose rate at contact should not exceed 5 μSv/h.
ISOLDE General:
- New delivery date of the bld. 508 was given on November 3, 2014.
- The door window at the entrance to the ISOLDE hall is damaged. This has been reported and should be replaced shortly. Users are asked to open and close the door carefully, avoiding further damages.
- The bushes around the stair leading to Rte Democrite have been finally cut.
AOB:
- The posters for the fixed experiments at ISOLDE are now ready and can be placed in the hall.
- The meeting was followed by two seminars of summer students from ISOLTRAP.
- Next PG meeting will take place on Wednesday at 2pm and it will be followed by a seminar of Gry Merete Tveten on “Spectrometers and mass separation for HIE-ISOLDE” https://indico.cern.ch/event/339066/.
Minutes taken by MS