1. HIE-ISOLDE Design Study Safety and Beam Quality Challenges for the HIE-ISOLDE Frontend Jacobo Montaño (EN/STI/RBS) HIE-ISOLDE Workshop, November 2013 * The research project has been supported by a Marie Curie Early Initial Training Network Fellowship of the European Community’s Seventh Programme under contract number (PITN-GA-2010- 264330-CATHI)

2. HIE-ISOLDE Design Study Outline Brief description of the ISOLDE-frontend Expected requirements for HIE-ISOLDE Extraction optics From single stage to double stage extraction Prototype Thermal, electrostatic and particle tracking simulations Off-line lab 2

3. HIE-ISOLDE Design Study ISOLDE-frontend For ISOLDE, the frontend is the machine that hosts the target chamber and produces the radioactive ion beams (RIB) There are two of these machines installed On-line at ISOLDE Frontends (1,2),3,4 Frontends (5),6,7,8,9 Much accumulated experience at ISOLDE… Ready for another frontend upgrade!

4. HIE-ISOLDE Design Study ISOLDE-frontend Target chamber coupling Vacuum …to be improved: Vacuum Target coupling Electrical connections Target cooling Target valve Ion extraction system Target valve

5. HIE-ISOLDE Design Study Requirements for HIE-ISOLDE HIE-ISOLDE will bring an important increment in the radiation levels at the target area Dose @0.5m from target: 6.3 Mgy → 31.5 MGy Only few polymers present a radiation hardness high enough to resist the HIE-ISOLDE expected doses These materials are often essentials for vacuum seals as well as for thermal and electrical insulations H. Schönbacher, A. Stolarz - Iycka. CERN Report: COMPILATION OF RADIATION DAMAGE TEST DATA. PART I: Cable insulating materials.

6. HIE-ISOLDE Design Study Extraction optics The positioning of the extraction electrode represents, at the moment, a degree of freedom for the extraction optics The electrode tip is removable. This operation requires human intervention, but it’s necessary when this tip gets dirty Neutral material can condensate on the insulator surface, worsening its performance The extraction system mechanism allows the axial positioning of the electrode The presence of a mechanism represents by itself a factor of mechanical failure risk The system takes between one and two minutes while performing its entire path; no fast valve closing is possible in case of emergency

7. HIE-ISOLDE Design Study Extraction optics For a single electrode: Close to the electrode the gradient is bigger than 1kV/mm 1kV/mm

8. HIE-ISOLDE Design Study Extraction optics Extracting with two stages can reduce the mentioned risks 60 kV57 kVGround 1kV/mm

9. HIE-ISOLDE Design Study Electrode prototype A prototype has been designed, constructed and assembled. The main idea: Electrode – valve integration

10. HIE-ISOLDE Design Study Extraction optics Thermal simulations Electrostatic and particle tracking simulations The thermal contact conductivity value becomes crucial for this analysis thermal measurements ongoing The minimum beam losses against the electrode is the optimization criterion Beam losses measurements ongoing

11. HIE-ISOLDE Design Study Extraction optics Optimization with particle tracking Beam losses For larger acceleration distances the beams are smaller and easier to transport to the ground electrode. The aperture doesn’t seem to produce any effect on the focusing, but for larger acceleration distances the largest apertures present beam losses

12. HIE-ISOLDE Design Study Extraction optics Setup for measurements on electrode: Insulated and modified “valve”: -Electrode body integrated -Instrument ports

13. HIE-ISOLDE Design Study ISOLDE Off-line lab 2

14. HIE-ISOLDE Design Study Summary Currently there are installed and operating 4 frontends and one spare frontend HIE-ISOLDE will require an upgrade of the frontend in terms of safety but keeping the beam quality The extraction system is targeted to be upgraded A two stage extraction prototype has been constructed and is being tested at the new ISOLDE off-line lab 2

15. HIE-ISOLDE Design Study Thank you for your attention! Questions?