1. Technical news:
· The robot handling the GPS targets developed a problem last week after the target change. It was determined that a spare part will need to be delivered, with the delivery date estimated at 6 weeks. During that time use of the proton beam on GPS would be impossible. An empty target was put on place manually on Friday following the RP ALARA procedure in order to use stable beams and keep the front end under vacuum. In the mean time the supplier found a way to deliver the part within 2 weeks. In that case the work on GPS will be resumed faster without the need to cancel any experiments and by only shifting this week’s solid-state- and bio-physics run to HRS.
· ISCOOL was opened to fix the problem with sparking of extraction electrode and problems with holding HV. The suspected insulator was indeed damaged and was replaced. Several other insulators were found a little damaged, but the intervention would require dismounting the ISCOOL which would mean that no ISOLDE separator would be operational. The ISCOOL was put together on Friday morning and now works properly, and it is hoped that the remaining insulators will last until the long CERN shutdown.
· After the ISCOOL intervention, a faulty cable was identified in the HRS separator area which explains the large steering recently needed to get the beam into the ISCOOL.
· The cause of a sudden stop of target cooling 1.5 weeks ago was found: during the previous intervention a valve had been forgotten in closed position causing further problems. This is now corrected.
· The target installed on HRS broke after a few hours of operation. It was replaced rapidly for a spare unit used in 2009 in order to provide beam during the weekend.
· New controllers for the HRS Tesla meters have been installed, due to recent problem with loss of communication with the devices.
· REX trap was used to bunch the ISOLDE beam for the WITCH setup.
· A more powerful vacuum pump was installed at REX linac, which already helps to improve the vacuum and hopefully the efficiency for highly-charged beams.
· This week REX provides stable beam for Machine Development and for MINIBALL.
· RILIS prepares for the online run with a low-work-function target to suppress surface ionization in the rare-earth region. They will provide Nd beam for MINIBALL and will possibly test offline the Pr ionization.
2.Physics and schedule:
· Due to GPS problems last week the WITCH run on 35Ar was shifted from GPS to HRS. The new CaO target was mounted on Thursday and showed signs of ageing and broke on Thursday evening. A used target from 2009 was ready as a backup and was mounted on Friday while the ISCOOL was being closed up. Thanks to extremely efficient work of the ISOLDE target and operation teams the beam was through ISCOOL and REX-trap by Friday midnight and the proton scan and yield checks were made exceptionally on a Saturday. This is highly appreciated by the WITCH team. WITCH recorded 35Ar data until Monday morning. The yield was lower than expected and in addition WITCH suffered from high background, so a thorough data analysis is required.
· This week, solid-state- and bio-physics collections of Cd isotopes take place on HRS and LA1 beamline (shifted from GPS). 4 proposals and 2 letters of interest take data until Monday morning for PAC and bio-chemistry studies.
3.Safety
· Urgent ALARA procedure was applied to put manually the GPS target on. Thanks to a quick response from several involved persons all signatures were collected just in time.
· Users are reminded to mark properly when they take and return ISOLDE radioactive sources.
4.A.O.B.
· The schedule for the second half of the year will be released soon.
· Consider the EURISOL-NETmeeting at CERN on Monday and Tuesday next week.
· The deadline for registering for Ecole Joliot Curie is June 23. The program is quite intriguing.
· Antoaneta Damyanova (Sofia University) joined MINIBALL as a summer student.
5. Seminars:
· Tim Giles presented the status of ISCOOL after a successful repair last week.
· Piet Van Duppen gave a physics coffee on “Quantum behavior of neutrons in a gravitational field”.
· On Friday 24 June at 11 am there will be a seminar by Mr. Markus Jaeger (University of Leipzig) about “DIGIPAC - a real time digital Perturbed Angular Correlation spectrometer”.
· For more information and links to the slides please visit the ISOLDE - seminars page.
Minutes byDTY and MK