Minutes from ISOLDE Physics Group meeting, 10th August 2016.

No comments to the minutes from the previous PG meeting: 

Please read the minutes.

Technical news:

• Overall it has been a good week from the operation point of view.
• The LINAC 2 proton source is deteriorating – there are minor interventions to keep it running and investigate the problem.
  
  • A technical stop is planned in September during which a more complete repair is foreseen.

ISOLDE:     

• HRS:
  
  • Was the only separator running last week, delivering Al for COLLAPS.
  • Was an overall smooth run.
  • Magnets stopped cycling 2 times. To cure the issue the local reset was needed.
    • It used to happen during mass change, but it has also happened unexpectedly.
    • The cause of this behaviour is still unknown, quite intermittent.

• GPS:
  
  • Was in stand-by mode last week.
  • Target #580, new SiC, was installed Tuesday and the setting up is ongoing.
    • ISOLTRAP will take Mg beam.
  • During the setup and for unknown reasons, the position of the extraction electrode changed. This caused the HT to trip often. Took some time to discover this error.
  • Experts could change the position back to normal, no damage was found and the problem didn’t re-occur.

• RILIS:
  
  • The new installed beam gate (10 kHz) for the Al-run worked fine.
    • Gained a factor of 3 in selectivity, but lost a factor of 2 in yields.
  • Saw a surprisingly large laser enhancement factor of 2000 at the beginning of the run, but dropped to the more expected factor of 200 at the end of beam time.
    • Maybe release of ionised coating/surface in the beginning, e.g. during the heating of the Al mass marker.
  • Now setting up “VADLIS” for Mg-run at ISOLTRAP.
    • If working well, this should give a cleaner beam.
• REX/HIE:
  
  • It was discovered that the setup was running on a local timing and not the global HIE-ISOLDE timing. A small switch had been overlooked.
  • With the global timing switched on, the beam was lost and it seems more difficult than expected to retune and rephase the frequency of the beam. 
  • The power converter of 7-gap keeps killing the fuse – this appears to be a design issue.
    • A meeting will take place to address this.
  • HIE-ISOLDE is ready for beam commissioning and now waiting for the delay at REX to retune the beam and for the beam permission.
  • The main tests have been completed, and there is negligible heating of the RF coupler, currently only reaching about 36K. Furthermore the temperatures are stable with continuous running.
  • By floating the “shorted” solenoid (i.e. not grounded) allows a max of 50 A which is sufficient for good transmission of the beam across the cryomodule (an interlock is in place to prevent higher intensities to avoid possible quenches).

• Targets:
  
  • #580 SiC installed on GPS for Mg beams
  • The nano-UCx (prototype) #581 target will be tested Monday. Maybe new future target material.
  • Target delivery/production is on track.

Physics:

COLLAPS:

• They measured Al isotopes from 26 to 32 from the HRS.
• Observed a larger line width than expected.
• Saw an indication of a peak from the Al-26 isomer.
• They had 63% transmission using the bunching mode.

• ISOLTRAP:          
  
  • They will take Mg beams from GPS.
  • First time they will be measuring in this mass-range and want a precision of 10^-9.
  • Will measure the Q-value from 23Na to 23Mg , and also 21Ne to 21Na.

Safety:

• HIE:
  
  • Please clean around the HIE area. This is important for the beam permit.

AOB:

• 275:
  
  • Some sorting is taking place to clear the floor. Pictures have been sent around for people to identify stuff.
  • There will be some works in the building. A optical fibre will be installed around 22-23 August for the neighbouring “barrack/building” which have recently been put in place.
• 508:
  
  • The door handle broke again (ground floor lab entrance) – a ticket has been opened.
  • A meeting regarding the air condition installation will take place tomorrow.
    • 2 separate systems are needed due to the restrictions of the controlled area.
    • Installation of the tubing for A/C should be done between Dec-Feb.

• Summer students
  
  • It is desirable that during the presentation the Supervisor is present.
  • The summer students presentations were:
    • Christoph Pohl: “GLM Implantation chamber”.
    • Jiayang Yan: “Yeild check and beam energy measurements”.

The next ISOLDE PG meeting will be held on 17August 2016 followed by three summer student presentations from, Ian Yap Chang Je, Giannis Savva, and Diana Valverde.

Minutes taken by ~TEM