Main Technical News:
- All scanners are calibrated
- In week 16, both separators failed temporarily. On GPS, it was because of a fuse, on HRS either the Tesla meter or a communication problem between power supply and server. It is now under discussion whether to change the magnet probes.
- The fast beam gate, which was installed on GPS for IS 532 exhibited problems (the duty cycle was limited to 0.3 instead of ~0.001 and the repetition rate to 1kHz instead of 10kHz) and was taken out to be sent for repair. The beam gate was implemented for the run of ISOLTRAP which is running at a repetition rate below 100Hz and a duty cycle of about 0.001. It is under discussion to find guidelines for the usage of normal or fast beam gate for all users.
- The automatic mass scan on GPS is not working. Emiliano will work on it during the summer
- The RFQ had various problems in the last two weeks concerning unstable voltage reading, inverted polarity as well as vacuum read-out. These have been solved.
- A UC-q-n target #473 has been setup at HRS, with which now there is only little beam through the RFQ.
REX/RILIS:
- Despite some beam-gate and RF problems at REX, the LINAC was setup and beam was delivered to MINBALL for offline tests.
- The new Ti:Sa pump laser has arrived as exchange for one sent for repair allowing RILIS to switch faster from one to another laser scheme. During the Ca run, RILIS experienced some laser spatial stability problems. However, the AC is finally stable at around 27°. The RILIS e-log is now available to users.
- The TTL pulse for the RILIS shutters is available on patch panel 4.
- RILIS lasers are now on Cd.
Other Information from Technical Meeting:
- Faraday Cups: YGPS.FC490 might read a factor 1.5 – 2 more than CA0.FC68. YCC0.FC90 shows fluctuations. Magda will mention this to Gerrit Jan Focker. In addition, YHRS.FC490 had been blocked because of a problem with pressurized air, which has been resolved in the meantime. YHRS.FC520 scales are not working properly. All XXX.FC510 cups were not working, this was now remedied.
- The target-heating ramping cards are still causing problems, however, since this is not an ISOLDE responsibility, it has to be looked after by CERN control team.
- Many elements in parts of the beam line (GLM/GHM, LA0, central beam line) had different problems, one concerning the application of voltages. This has been solved by resetting the device on a level higher than the normal user mode. You are reminded once again to please check your equipment arrays (which can be done anytime without disturbing ISOLDE operation since you do not need beam for this).
- Since April, there was only 1 computer for all ISOLDE controls which considerably sloweddown the response from power supplies etc. Last week, three front-end computers were added: 1 for GPS, 1 for HRS, 1 for LINAC, 1 for REX.
- VISTAR: The RILIS status (on, off, standby) can now be seen in the vistar. The status of the magnets has also been implemented in the respective vistar, however, it is correlated to proton request and seems to be off by almost half a mass unit.
- The offline pump stand was contaminated by the salt targets from last year, which caused corrosion of Ta transfer lines . The problem has been now solved.
- Be aware that switching off the ISOLDE beam gate, might switch off the whole NIM crate.
Physics/Schedule:
- GPS: The Ta/W + CF4 Target #472 broke and was replaced by a used YO-HP target. THE ISOLTRAP tape station has been successfully tested at LA1 within IS 537. The collections of IS 437 (Bertram Blank) were successful. The test of a new measurement technique at ISOLTRAP within IS 532 was successful in the sense that enough data were collected for a proper analysis of the achievable uncertainty. The molecule break-up tests in REX-trap with fluorinated molecules were not successful due to low molecule intensity.
- HRS: The used molten Sn target #449 worked well for the study of neutron-deficient Cd isotopes within IS 497. Isotopes below A=100 could not be reached because of the rapid drop in yield connected to the slow release of molten metal targets. Since the COLLAPS run started and finished early, the beam was used at ISOLTRAP for stable-beam tuning of the central beam line.
- GPS: Tests for a diffusion chamber are ongoing.
- HRS: The UC-q-n target #473 is being set up for the COLLAPS experiment IS 497 on neutron-rich Cd isotopes. COLLAPS will take beam starting from 26.4. Proton scan and yield measurements will happen on 27.4. MINIBALL will use the target afterwards within IS 524.
- The second part of the schedule (June – August) is foreseen for the end of this week.
- Protons will be available until December 3rd, the last week being protons to ISOLDE only.
Safety:
- ISOLDE will become a construction site as of 2013, making hard hats and safety shoes mandatory.
AOB:
- India has joined the ISOLDE Collaboration. The MoU was signed last week in Kolkata.
- There was an ENSAR meeting held at CERN. For ISOLDE, the budget is fine.
- In 2013, ISOLDE, GANIL, and GSI will undergo big maintenance phases. However, 10,000 hours of beam time are available at JYVÄSKÜLA.
Presentation:
- There was a presentation by Stefan Fritzsche on the progress in atomic theory calculations.
- There will be no seminar next week.
Minutes taken by SK