Chairman: Karsten Riisager

Scientific Secretary: Mats Lindroos

Present: Jonathan Billowes, Yorick Blumenfeld, Peter Butler, Valentin Fedosseev, Roland Garoby, Alex Herlert, Mark Huyse, Marek Lewitowicz, Mats Lindroos,  Karsten Riisager, Thierry Stora

Excused: Thomas Otto, Piet van Duppen, Jacques Lettry, Roberto Losito

1. Minutes of last meeting

• The minutes from the last meeting were approved.

2. Follow-up on RILIS, efficiencies and priorities (VF)

• Valentine Fedosseev gave a presentation (see file below) on the progress at the RILIS and LARIS systems. The new solid state laser from Edgewave for the on-line RILIS system has been installed and operated with ionization of stable Ga. The laser delivers a total of 150 W (1 green beam, 1 UV beam and 1 IR beam) compared to 80 W (1 green beam, 1 yellow beam) for the CV lasers. The optics is different for the new lasers as the beam has a different transverse profile compared to the CV lasers. However, the optics issues has been possible to overcome but some spectroscopy work remains to make the lasers fully operational for all elements previously ionized at ISOLDE.  The spectroscopy work can be done off-line (in the LARIS) and consists of identifying new ionization schemes for elements requiring wavelength which can't be supplied with the new laser system. A table has been prepared showing which elements has to be revisited (6 out of 26) and the upgrade group agreed that this work should be the first priority for the LARIS lab. The estimate is that it will take up to a week per missing "wavelength" . The first RILIS runs in the 2008 will be done with the CV lasers as there are missing "wavelengths" in the ionization schemes but after that the new system will be used extensively. The new lasers will also enable more remote controls for the RILIS system which eventually should remove the need of having RILIS staff at ISOLDE night time during runs. The RILIS home page gives a lot of information on the RILIS and LARIS systems, information such as details of the used ionization schemes and efficiencies can be found. The LARIS lab can also be used for spectroscopy work of ionization schemes for TiSa lasers which could be important for our collaboration with other labs.

3. Injector upgrades at CERN (RG)

• Roland Garoby gave a presentation (see file below)on the planned injector upgrades for CERN. The first step is the construction of linac 4 which already is approved and which should deliver beam for the PS Booster 1 March 2013. This first step could yield twice the intensity (6.4 E13 p/p) of today per booster pulse to ISOLDE and it could be combined with a faster cycling of the PSB (0.9 seconds). To take the increased intensity per bunch for ISOLDE important modifications of the target and target area are required. The next step for the injector upgrade is the LP-SPL (Low Power Superconducting Proton Linac) which could have a beam line for ISOLDE capable of delivering a beam of 1.4 GeV, 42 kW in a long pulse ( 1.2 ms) every 0.6 s. The same system could at 2.5 Gev deliver 75 kW in a longs pulse (1.2 ms) every 0.6 s for a first EURISOL direct target station. The plan is to have LP-SPL operational in 2017. The final step for the SPL is the High-Power version which could deliver 3 or 6 MW of protons for EURISOL at 2.5 GeV at 50 Hz in long pulses. At a later stage an upgrade to 4 MW for both EURISOL and a neutrino factory is in envisaged. The HP-SPL could be ready earliest in 2020.

• Peter Butler pointed out that all this is great news for future RIB physics at CERN-ISOLDE and maybe EURISOL. He stressed that it would be very interesting to study the consequences of a faster repetition rate for LP-SPL to ease the thermal stress and shock wave effects on the ISOL targets. Roland answered that such a study could be done but that he believed that it would be a costly option as the faster cycling rate would require considerable cooling and RF power for the cavities even if the average beam power is kept well below the ultimate multi MW capacity.

• The ISOLDE community has had a representative in the previous SPL working group and Roland welcomed a continued presence of somebody from ISOLDE in SPL project working group.

4. Priorities for target and ion source development (AH, TS)

• Thierry Stora presented (see file below) the R&D on target and ion sources at ISOLDE since the last upgrade group meeting and the wish list for the coming period. The priority request to reduce the Cl background in the ³⁵Ar beam from a CaO target with a cold plasma source has been achieved through an improved cleaning procedure of the target and line. A target with a mini-mono ECR source with Y²O³ nano-grained target material was successfully tested and improved yields of ⁷²Kr and ¹⁰C were recorded. Further improvement of the ⁷²Kr are required before the proposed experiment for this isotope can be done. The mini-mono ECR source needs a better RF transmission system (RF guide rather than cable) for long term operation. The mini-mono ionized beam was successfully injected into REX trap.  A TiF³⁺ beam was successfully extracted off-line which means that the proposed Ti beam experiment can advance. The selective trapping of Fr for production of a Tl beam will soon be tried with a new version of the quartz line target. The main problems for 2008 is the lack of staff in the Target and Ion source development team and all contributions are welcome. Priorities for 2008 were discussed, on the wish list are:^148,150BaF (lanthanides suppression) at REX, ⁷⁵Cu (⁷⁵Ga suppression) at REX, ⁷²Kr at REX, ¹⁴⁰Nd, ¹⁴²Sm, combining ThO/low work function cavities/RILIS (LoI), ²²Mg (²²Na suppression) at REX (LoI), Negative ion beams and from this last INTC: ³⁵Ca and  BaCl beams. Main priority for 2008 is the rare earth developments, including ¹⁴⁰Nd and ¹⁴²Sm.

5. News from AB concerning HIE-ISOLDE and upgrade work (ML)

• Mats Lindroos Lindroos presented (see file below) the status of the HIE-ISOLDE proposal. The collaboration has raised 50% of the money required for the first phase of HIE-ISOLDE (5.5 MeV/u energy upgrade). The money raised are contribution from mainly Belgium (Linac R&D and construction), Sweden (RILIS) and UK (RFQ cooler) with many smaller contribution from other members. A grant application is in progress in the UK for the linac to enable the full linac upgrade to go ahead, a pre-proposal is in progress in the USA for the development of a high intensity EBIS system and a pre-study has been done in Finland for new robots for ISOLDE. A WP in the I3 EUCARD will support development of sputtered SC for linacs like those proposed for HIE-ISOLDE. The R&D work on the HIE-ISOLDE linac is presently organized as an externally financed activity in the AB, AT and TS departments. The next step is to get full project status at CERN. To prepare the proposal in the UK and govern the work presently in progress a steering committee will be formed and and review panel appointed. It was agreed to ask Alex Mueller to chair the review panel. The main grant holders and grant proposers will discuss the members and mandate of the steering committee and report back to the next meeting of the upgrade group.

6. AOB

• The scientific secretary pointed out that this was the last meeting of the present chairman, Karsten Riisager. The upgrade group expressed its gratitude for his excellent chairmanship and wished him success for his return to Denmark. The committee also welcomed Yorick Blumenfeld who will take over as chairman of the upgrade group from the next meeting.
• The next meeting of the upgrade group will take place 4 November 2008 at 14:00.

Minutes by Mats Lindroos