Minutes from ISOLDE Physics Group meeting, 24th August 2016.

No comments to the minutes from the previous PG meeting: 

Please read the minutes.

Technical news:

• Overall it has again been a good week at ISOLDE.

ISOLDE:     

• ISOLDE:
  • The tape station is not behaving correctly.
    • This will be investigated ASAP by G. Jan Focker
  • A “burning smell” was noticed in the hall.
    • It turned out to be a bad belt in the ventilation system. The belt was replaced.
• HRS:
  • Delivered Ra beam to CRIS from Wednesday.
  • The Mag90 went into fault 2 times in 3h
    • A power cycle of the controller cured the issue.
  • The run continued until the target delivered a leak Tuesday morning.
    • This can be expected from an old target that has been used for about 2 weeks in all and which had taken 6e18 protons.

• GPS:
  • Delivered Beam for ISOLTRAP until Wednesday
  • Setting up the Hg beam
    • The extraction electrode again went into position 64 without setting it to this value (some default position).
    • This has now happened 2-3 times, the reason is still unclear but it seems to be related to the controls.
  • The VISTAR information on the Mag70 is in error – to be fixed ASAP.
    • A new software update was installed.
    • It does not display the mass value.  
    • But when Green all is fine. Only Red is a real error.
  • It was problematic to tune the beam at 30 keV to LA1.
  • A retuning of the separator at 50 keV was performed and this gave better transmission.

• RILIS:
  • Had a good Ra-run for CRIS.
  • Now setting up for Bi-run.
    • Together with ISOLTRAP and COLLAPS they want to further investigate a strange isomer state of Bi, that may have been observed during the windmill/ISOLTRAP run this year.
  • Plan to install new shutters (similar to installed at AWAKE) for laser blocking during the shutdown period.

• REX/HIE:
  • Pulses are now stretched to 1 ms.
  • There were problems with the 7-gap III amplifier which was limited to an A/q of 4.0. To go beyond this to A/q = 4.3 (for 2016 physics) a bigger intervention than expected was required and this resulted in a day of downtime.
  • A Si-detector (after the first cryo-module) had to be replaced.
  • Beam is now through the 4th Cryo-module at 3.9 MeV/u.
  • Although the cryo-temperature controllers are working ok – work is needed to make the control perform more stable. With each new cryo-module turned on the system becomes unstable. Discussions are ongoing about stabilising the system.

• Targets:
  • The production of first targets for the HIE-run is on time.  Nano-UCx (prototype) #581 target was not installed as it was a bad target, due to issues with a new polymer material that turned out to be very reactive.
    • The new polymer was used to speed up production time.
    • This is to be investigated.
  • Used targets will be installed on both HRS and GPS for the next beam time.

Physics:

• CRIS:
  • They studied the hyperfine structures of neutron-rich Radium isotopes, 222- to 234-Ra.
  • Overall a good run and they are happy.
  • The 2-3 days of extra run was well used.
  • They changed between low resolution and high resolution scans to map out the hyperfine levels.
• LA1:      
  • A traveling setup, TATRA, will take 188Hg-beams from GPS.
  • They want to measure conversion electrons.
    • For this purpose they have window-less detectors and need a high vacuum.
    • The vacuum perform well also with open to ISOLDE target.

• GLM:
  • On standby is Mossbauer for biophysics using 197Hg decaying to 197Au.
    • Study the binding of Hg in molecules.
    • Want a few collections for feasibility test, as this study has never been done before.

Safety:

• Target:
  • Due to the bad nano-UCx target produced last week (the reactive polymer), the safety issues regarding the handling and procedure for nano material will be reviewed.
    • The production of nano-targets are on hold.
    • This pause will have no effect on the remaining beam times for this year.

• ISOLDE:
  • The access to ISOLDE should no longer have a delay (3 min) on the “2nd access”.
• TSO:
  • Magda is the new TSO of b275, replacing Maria who becomes the DTSO.

AOB:

• EDH:
  • The CERN EDH system will change 31 August (likely a few days earlier).
    • Please plan ahead your orders for instance LN2, as moving to the new system could result in system errors.

• LN2 delivery:
  • Please do not remove the adaptor on the empty dewar for refilling.

• 508 workshop:
  • A power adaptor (German to Swiss) for the vacuum cleaner has been ordered.

• Summer students:
  • The summer students presentations were:
    • Thomas Guldager Skov: A Plasma Ion Source for ISOLTRA
    • Ingrid Strandberg: Linewidth simulations & offline ion source for MIRACLS

The next ISOLDE PG meeting will be held on 31 August 2016 followed by two summer student presentations from: Kritsana and Kris Gavana

Minutes taken by ~TEM