1. HESR 2 Electron Cooling Björn Gålnander The Svedberg Laboratory Uppsala University Midterm Review, DIRACsecondary-Beams December 8, 2006 GSI, Darmstadt

2. Outline HESR Electron cooler Present project status Outlook

3. Antiproton momentum, 1.5 –15 GeV/c Cooling to counteract PANDA pellet target Electron cooling up to 8.9 GeV/c (4.5 MeV electron energy) Stochastic cooling above 3.8 GeV/c High Energy Storage Ring HESR is presently being designed in a consortium formed between FZ-Jülich, GSI and UU The electron cooler is the main responsibility of Uppsala University.

4. HESR Electron Cooler e-beam parameters:HESRFermilab Energy (MeV)0.45 - 4.54.3 Current (Amp)10.5 Solenoid field (T)0.20.01 Straightness (µrad rms)10200 The cooling force needs to be stronger than at Fermilab to counteract the internal target Higher magnetic field Better straightness Parameters for the HESR cooler:

5. Objective of Design Study Task 12, HESR 2: Electron cooling Description of work: construct prototypes of several critical parts of the system CELSIUS electron cooling system will be used as a test bench An important part of the work will be to construct prototypes of several critical parts of the system. The exact content of the prototyping work will be determined in the course of the study. The CELSIUS electron cooling system, which will then be taken out of use for its purpose at the CELSIUS ring, will be used as a test bench, and will be used to test electron beam diagnostic equipment as well as to make tests related to the high-voltage behaviour of the system. the problems to create the required quality of the magnetic field and stability of the high voltage will be investigated. Other aspects of the electron cooling system, including the method to charge the high-voltage terminal, the problems to create the required quality of the magnetic field and stability of the high voltage, the required ultra-high vacuum and the electron beam optics and stability of the electron beam transport will be investigated. final report In the final report all experience will be summarized, drawings will reflect the status of the component development, and a first design of a control system for this high power device will be suggested on the basis of the accumulated experience.

6. Present Project Plan Different sub-projects, responsible persons Design high-voltage column G. Norman, A Shemyakin Test prototype high-voltage solenoidG. Norman Design magnet system for electron beam transport K. Rathsman, D. Reistad Design and test magnet field measurement system T. Bergmark Design vacuum chamber, make prototype T. Bergmark, O. Byström Design and test prototype scraper B. Gålnander, T. Lofnes, Design electron gun and collector G. Norman Tests on high-voltage regulation at Uppsala Tandem Pelletron T. Bergmark

7. High Voltage Column Gun Collector Pellet chain HV solenoid High voltage solenoid prototype Cover delivered Coils mounted and delivered Feb. 2007

8. Sections of 3 metres (24 m total length) Pancake coils (normal conducting), individually adjustable to achieve 10 μrad rms straightness Magnet system Scraper and pick- up electrodes. Horizontal and vertical dipole windings. Deliverable 29, Report on solenoids and toroids, delayed Design revised, making coils smaller and less expensive, saving about 30 % of copper. Superconducting alternative is also considered

9. Measurement carriage and sensor head Prototypes are being manufactured Test will be performed during 2007 Magnetic Field Measurement System needed for pancake alignment Prototype test set-up Carriage prototype

10. Vacuum Chambers with rails for the Magnetic Field Measuring System Test tube of 1 m, two sections of 2.8 m will be delivered week 5, 2007

11. Scraper tests at the CELSIUS cooler Modification of CELSIUS cooler for scraper tests with electron beam Scraper prototype delivered next week Coils are being manufactured, delivered week 5, 2007

12. Outlook During spring 2007 several prototype tests will take place Autumn 2007, test evaluation and final report work No overall delay expected, HESR 2 will be finished by Feb. 2008. However, the Deliverable D29, “Report on solenoids and toroids”, is delayed until 1 March, 2007, since this sub-project has been given more weight compared to the original planning.

14. Dag Reistad, Task Leader Torsten Bergmark Björn Gålnander, Deputy Tomas Johnson Tor Lofnes Gunnar Norman Olle Byström Stefan Johnson Tord Peterson Karin Rathsman Present group members Collaboration with IKP (Ziemann, beam dynamics), MSL (Danared, magnetic field calculations), BINP Parkhomchuk et al., Fermilab, A. Shemyakin et al.

15. Thank you!

16. 4.5 MeV tank 8 MeV tank Layout

17. CELSIUS electron cooler Principle of electron cooling Low energy cooling is a well established technique. CELSIUS cooler was used to cool protons and ions up to 500 MeV/nucleon

18. Pick-up electrodes: To measure positions of antiproton and electron beams with resolution of 10 µm. Scrapers: To measure envelope oscillations of the electron beam. Pick-up Electrodes and Scrapers are combined in one unit