ISOLDE Physics Group Meeting 03/05/2017

Technical news

• HRS

- Vito (35Ar) were the main users (IS601) with 1 shift for IDS taking (17N) for

calibrations.

- There was a mix up when switching beam settings between IDS and VITO,

which lead to lost time at VITO.

- No changes had been made to target parameters when switching (as

agreed; may need to re-use this target for VITO later this year).

- However, overlapping arrays meant parameters were

overwritten/changed.

- In addition the RFQ settings could not be recovered due to a new software

limit, which had been installed earlier that day

- This has since been removed, but was implemented to prevent overheating

of the amplifier.

- Tim/Stuart are making a manual to prescribe the future operation.

• GPS

- Proton scan took 6.5 hours due to badly setup separator; the beam was

poorly set up on the horizontal plane.

- It was noticed that an element had drifted.

- Fixed/noticed at 5pm and p+ scan completed, but no yield measurements

were possible due to this delay.

- Independent HV trips on both the target and the line. No reason found e.g.

no vacuum spike, but this has been seen many times before.

- Drift in magnet field/voltages reported by IDS. Tuning appeared to not be

optimum and transmission drifted to 10%; recovered to 65%.

- The cause could not be identified, but Timber will be used to look at the

data. Data from scanners etc. not possible yet. Elefteris is coding this into

the system.

• REX/HIE

- Bake out of REX is finished.

- Cooling of cryomodules has been improved, which will lead to fewer trips

during operation.

• RILIS

- Indium setup continuing for upcoming runs at IDS and CRIS.

• Targets

- #595 worked well last week.

- #597 being installed now.

- MEDICIS monotrack system was used, meaning that the time to change the

target was reduced from 2 hours to only 30 minutes, and no access was

required in the zone.

Physics news

• VITO

- β-asymmetry studies with 35Ar.

- Motivation is fundamental physics and the Vud matrix element.

- Preliminary studies searching for appropriate crystal that can operate at

high temperatures, whilst maintaining the polarization for a long time.

Relaxation time vs. nuclear lifetime.

- Avoid low temperatures (<100K) as much as possible to prevent freezing

dirt onto the surface of the crystal.

- Total of 5 candidate crystals, 2 measured in this beam time.

- 1st crystal showed some asymmetry at low temperatures (~10K).

- 2nd crystal (NaF) maintained reasonable asymmetry at room temperature.

Magnitude is 10x more than 1st crystal, but still not huge.

- Polarisation of lasers should also be checked.

• IDS

- 133Sn being studied in β-decay of 133In. Also had 134In β-n decay.

- Motivation is the single-particle structure with one neutron outside of the

doubly-magic 132Sn core.

- Chances to use RILIS lasers to make isomer selection, enhancing

population of low-spin or high-spin states in the daughter nucleus.

- Neutron ToF spectra obtained and states have been identified.

- Goal to make coincidences between neutrons and gammas; analysis is

ongoing.

- A lot of contamination on these masses for Cs: 20 kBq at mass A=133 and

65 kBq at mass A=134 (in only 8 hours). T1/2 = 10 yrs and 2 hrs,

respectively. IDS passed on this advice to CRIS for the following run, which

will explore a similar region.

• CRIS

- Laser spectroscopy of n-rich In isotopes.

- Motivation is again in the proximity to 132Sn and shell-closures.

- Everything beyond 128In will be new for laser spectroscopy.

- Aim to measure charge radii and moments via high-resolution hyperfine

spectra.

A.O.B.

• European Researcher Night

- ISOLDE would like to be involved, or at least CERN would like ISOLDE to be

involved, this year. It’s in September.

- Interest from French speakers would be good as much of the audience will

be the local community in the Meyrin region.

- If interested, contact Karl to discuss as the promotional material is

expected to be printed and advertised a long time in advance.

• Safety courses

- Nobody signed up for safety courses on 16th May yet. Please inform Karl or

it will be cancelled.

• Operations team

- New operator from PS who will take over piquet duties from Pascal. His

name is Simone and he is training and gathering experience.

• Setups

- WITCH will start up in the week of June 12th. The magnet will be ramped

up for a couple of days or nights and should be communicated with

accelerator people.

- A new policy of oil-free pumps in the HIE-ISOLDE extension is to be

adopted after contamination at Miniball last year.

- Dirty exhaust lines will be replaced before the campaign.

• INTC

- LOIs for stable and long-lived beams are requested at the next INTC

meeting in June.

Minutes taken by LPG