1. Technical news:
· There have been difficulties with beam transmission after mass-changes at GPS discovered by the users at LA1 and ISOLTRAP. It appears that the problem is related to the Tesla meter. The engineers are looking for a replacement identical with the Tesla meter used at HRS.
· A fan of a turbo pump at GPS stopped working a couple of weeks ago and this week an inspection from the vacuum group confirmed that it was broken. However, an intervention for repair or replacement work requires the ALARA procedure, which has already been initiated but will take time. In the mean time one hopes that the turbo survives without its fan functioning.
· The proton-intensity Watch Dog went on quite often during the experiments last week. PSB specialists are looking for the cause of the problem.
· REX solved some small issues. New version of the vacuum controls is in place. An additional turbo pump was installed to improve the vacuum in one of the sections. This helped, but in the meantime a cryopump in the same section broke.
· RILIS was used last week for thallium beams and now they are looking for auto-ionizing states in astatine, which may vastly improve the ionization efficiency.
2.Physics and schedule
· ISOLTRAP had a run on thallium. The originally planned neutron-rich Tl isotopes were not seen at the tape-station or at ISOLTRAP. Instead, masses of 184,186,190Tl have been measured and excitation energies of higher-energy isomeric states have been identified in the first two isotopes. 190Tl and 184Tl were successfully studied with the tape-station system. The experiment suffered from Fr contamination, especially on the neutron-rich side.
· In-source laser spectroscopy on 179-184Tl has been performed at LA1. The data contains information on the moments and the charge radii. The results include also intruder states found in 182,183Tl.
· End of this week a run on Coulomb excitation of 128Cd at MINIBALL will start, looking for evidence of collectivity and in general probing the shell structure close to N=82 and to the path of the r process.
3.Safety
· High radiation level was noticed at a FC in front of ISOLTRAP by a user with active dosimeter, even though the wall radiation monitors did not show alarm level. The cause was a faraday cup which was used to measure a very intense short-lived beam. There will be an official report following the incident and very probably small radiation detectors will be installed at several points along the beamlines. Based on this event, the message/reminder to ISOLDE users is the following: please pay attention to the beam which you take and to its intensity before taking it to your setup and measuring it in FCs; avoid using FCs other than FC490 with radioactive beam; once you’ve started measuring, pass with the hand-held monitor along the beamlines and along your setup to see if there is no increased dose; check in the control-room the readout of radiation monitors; be aware than for some masses there is a build-up of activity in the target and there might be intense radioactive beam coming out even some minutes after the protons had been turned off . For those working close to the beamlines, please check where the ion beam is going and avoid these beamlines. In case of any doubts or problems, please contact the machine supervisor. The use of active dosimeters is also discussed at the moment. We will inform you on the outcome soon.
· Finally we have a high-tech key cabinet at ISOLDE, which hosts all keys (radioactive sources, mechanical workshop, etc.). Access to the keys is done via the CERN magnetic badges with assigned access to the ISOLDE hall. Be aware that access events are being logged.
· During the last safety inspection it was pointed out that the condition of the ISOLDE kitchen, in particular the stove, is unsatisfactory. If the stove/oven remains in its current condition it will be removed at the end of August during the general cleanup of 507 and will be replaced by a microwave oven.
4.A.O.B.
· Six new chairs have been bought for the ISOLDE-DAC room. The room itself will be refurbished at some later point.
· Please contact Megan with materials to aid her work on the posters to present ISOLDE.
5. Seminars:
· Dr. Marcus Scheck (IKP TU-Darmstadt) presented "Experimental evidence for low-lying octupole isovector excitations".
· For more information and links to the slides please visit the ISOLDE - seminars page.
Minutes by DTY and MK