1. Andreas Jankowiak Institut für Kernphysik Johannes Gutenberg – Universität Mainz A Electron-Nucleon-Collider at the HESR of the FAIR Facility: ENC@FAIR K. Aulenbacher, R. Heine, A.J., W. Hillert, O. Boldt, A. Lehrach, T. Weis, C. Montag, D. Barber, P. Schnizer Common EIC / ENC Workshop GSI – Darmstadt 18 May 2009

2. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz A “simple” idea: electron – nucleon collisions using the HESR Luminosity considerations for a electron – “low energy” nucleon collider Some comments on the necessary ingredients First parameter sets for e-p collisions at s 1/2 =14GeV (3.3GeV e - on 15GeV p) Deuterons Conclusion The menu

3. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz A “simple” idea: ENC@FAIR (i) HESR SIS18 70MeV p-Linac HESR: anti proton storage ring 1.5 – 15 GeV/c (max. 50Tm) L=576m, e-Cooling, stoch. cooling PANDA fixed target experiment p SIS100 SIS300

4. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz A “simple” idea: ENC@FAIR (ii) P e-e- pol. e - -inj. idea emerged 08/2008 L > 10 32 1/cm 2 s s 1/2 > 10GeV (3.3GeV e -  15GeV p) polarised e - ( > 80%) ↔ polarised p / d ( > 80%) (transversal + longitudinal) using the PANDA detector as much as possible Common effort of German Universities (Bonn, Mainz, Dortmund) plus collaboration with Research Centres FZJ, DESY, GSI,... HESR pRing eRing PANDA 8MV eCool

5. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Luminosity Considerations (i) f coll : collision-freq., f 0 : revolution-freq., h p : number of bunches, n e,p : particles / bunch, r e,P : beam radii at IP,  IP : beta function @ IP,  p : proton beam emittance F HGR : hour glass reduction factor, F HGR ~ 80% for l p =  IP luminosity of an e-p collider, round beams, same radius B: bunching-factor = rf / l p (rf wave-length / bunch-length), L p : circumference  0 : electric constant = L p / l p · n p space charge (Laslett) tune shift: It turns out:  Q sc is the prominent limiting parameter !  Q sc < 0.1 !

6. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Luminosity Considerations (ii) rewrite luminosity formula using expression for  Q sc : (for the HESR case) ~ 1 ~ 0.1 ~ 0.8 the only free parameters: bunch number h p and electron bunch population n e Take care of other constrains, most parameters depend on each other.

7. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz beam-beam parameter electrons (< 0.05) / protons (< 0.01) Luminosity Considerations (iii) beam instabilities in pRing and eRing (depending on bunch current, bunch number, emittances momentum spread,...) synchrotron radiation issues beam cooling in pRing IP geometry: radius / opening angle (n-sigma values)

8. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Linac eSynchrotron eRing HESR (15GeV/c,  = 16) The HESR as pRing (i) n p =5.4 · 10 10, l p =0.3m,  p =1.2 · 10 -7 m rad (  Q sc =0.05) BetaCool calculations done by Andreas Lehrach / FZJ shows that these values could be reached (talk Friday morning) cooler-parameter: 8.2MV, 0 – 3 A, B=0.2T (magnetised cooling), T T =1eV, T L =0.5meV, B r /B < 10 -5, 24m effective cooler length h p =100, N p =5.4 · 10 12 f 0 =519.46kHz SIS18 70MeV p linac P 1.4GeV/c (only three spin resonances) tune jump Quads, partial snake eCool, 8.2MV full snake

9. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz To get the desired bunched beam of polarised protons with h p =100, l b =0.3m, n p =5.4 · 10 10,  p =1.3 · 10 -7 mrad, P p > 80% @ 15GeV/c into the HESR needs: a polarised p source at the new 70MeV proton linac spin manipulation in the SIS18 (tune jump quads, partial snake) proton transfer line + injection counter clockwise to the HESR spin manipulation in the HESR (full snake in back straight) accumulation of > 50 SIS18 shots at injection in the HESR (complicated process with bunching – bunch to bucket transfer – bunch merging) complicated rf-gymnastic at 15GeV/c in the HESR adiabatic bunching in h=100 under strong electron cooling  without eCool necessary cavity voltage would exceeds MV ! a powerful 8.2MV, 1 – 3 A magnetised electron cooler The HESR as pRing (ii) already included in the PAX proposal (A. Lehrach, talk Friday morning)

10. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz HESR electron cooler 4.5MV: FAIR Phase B (PANDA high resolution mode) Upgrade path to 8.3MV: beyond (PANDA high luminosity mode) 24m cooling straight, B r /B l ~ 10 -5 only 0 – 1A electron current HV generation: Pelletron (6bar SF 6, 94m 3 ) 150 pages Still lots to do ! The electron cooler (i) The Svedberg Laboratory Mai 2009 24m Due to lack of funding, Uppsala will not longer substantially contribute to the cooler! Group will be closed soon.

11. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz The electron cooler (ii) 2MV COSY cooler under development as prototype for HESR eCool (FZ-Jülich and Budker Institute / Novosibirsk) First demonstration and measurements of high energy magnetised cooling ! Scalable? 2MV  4.5MV (75 modules)  8.2MV (137 modules) HRJRG funded (450k€/3a, J. Dietrich/FZJ, Budker, Dubna, TU Dortmund) 2.5Mio€ + 1Mio€ funding for realisation High voltage module 60kV, integrated solenoids, powered by gas-turbine 0.03 – 2MV, 0 - 3A (34 modules) HV-column: B = 0.05 T toroids + cooling: B = 0.2 T New approach for high voltage generation

12. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz The eRing (i) bunch intensity: n e =2.3 · 10 11  19mA (in eRing with L e ~ L p =576m) h e = h p = 100  I tot =1.9A P SR =795kW@R=25m (HESR: R=30m) Power density: 5kW/m Synchrotron-Radiation: polarized e - -gun pulsed linac (~100MeV), full energy injector synchrotron “flexible” adjustment of emittance ? impedance budget and multi-bunch feedback system high synchrotron radiation load as in B-factories Linac eSynchrotron eRing (3.3GeV) e-e- W. Hillert, O. Boldt (ELSA / Bonn) Th. Weis (DELTA / Dortmund)

13. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz The eRing (ii) 24to dipole, 4.3to quadrupole both nc eRing dipole: ca. 0.4m×0.25m and 1.6to for 4m length Apparently it is a good idea to built the eRing inside the HESR tunnel ! But don't forget: - cavities - spin-manipulation - injection/extraction - feedback -...

14. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz The eRing (iii) electron spin must be vertical in arcs, otherwise  depol < 20min (D. Barbers / DESY, talk today) sc solenoids to turn spin from vertical to in-plane, directing inside or outside last bending in horizontal plane turns spin to longitudinal direction forward/backward sc-solenoid dipole  conditions to be fulfilled due to spin dynamics requirements:  a = n+½ (a=0.0011596) and  spin =  a  spin =90°) in our case: 1)  =6467  E=3.305GeV,  · a=7.5 and  =12.00° 2)  =5605  E=2.864GeV,  · a=6.5 and  =13.85° (-44% SR-power) Each arc consists of 15(13) 12.00°(13.85°) bending systems (DBA or some FODO derivative) The last/first used for spin manipulation ! Polarisation Preservation in eRing:

15. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz IR design (i) 30m PANDA

16. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz IR design (ii) e-e- p split-coil-quads or large aperture sc-quads head on collision aperture requirements: 20  electrons, 12  protons  IP =0.3m, r IP =0.19mm beam separation at 2.88m (no parasitic collisions) with small dipole field over IP ? no direct or indirect SR photons in detector combined quadrupole-dipole for beam separation (9kW SR power, E C =8keV) First guess: (C. Montag, BNL) special designed SR-absorber

17. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz HESR / 15GeV peRing / 3.3GeV L [circumference, m]576577.126 R [bending radius, m]3025  norm /  geo [mm mrad ]2 / 0.13  IP [m]0.3 r IP [mm] /  IP [mrad]0.197 / 0.63 l [bunch length, m]0.3< 0.1 n [particle / bunch 10 10 ]5.423 I b [bunch current, mA]4.519.1 h [bunches / ring]100 I [total current, A]0.451.91 P SR [sr-Power, kW] / [kW/m]795 / 5 f coll [collision freq., MHz]51.946 coll [bunch distance, m]5.765.7713  Q sc 0.05  [beam beam parameter]0.0140.015 Luminosität [1/(cm 2 s)] (inc. 80% hour glass red.) 1.1 · 10 32 P [polarisation, %]80% needs 8.2MV eCool 12 and 20 sigma acceptance requirements, physics requirements to be demonstrated (under FAIR/GSI constrains) First parameter sets (i)

18. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz HESR / 15GeV peRing / 3.3GeV L [circumference, m]576577.126 R [bending radius, m]3025  norm /  geo [mm mrad ]2 / 0.13  IP [m] 0.1 r IP [mm] /  IP [mrad]0.111 / 1.12 l [bunch length, m]0.1< 0.1 n [particle / bunch 10 10 ]3.623 I b [bunch current, mA]3.019.1 h [bunches / ring] 200 I [total current, A]0.603.82 P SR [sr-Power, kW] / [kW/m]1590 / 10 f coll [collision freq., MHz]103.892 coll [bunch distance, m]2.882.8857  Q sc 0.1  [beam beam parameter]0.0140.01 Luminosität [1/(cm 2 s)] (inc. 80% hour glass red.) 4.4 · 10 32 P [polarisation, %]80% First parameter sets (ii) needs 8.2MV eCool IR + detector design bunching process B-factory design x 2 possible under collision? polarisation preservation? polarisation?

19. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz e-e- Deuterons (i) Linac eSynchrotron eRing SIS18 70MeV sc linac P 3.8GeV/c (NO spin resonances) eCool, 4.1MV only partial snake possible + rf-dipole necessary tune jump Quads, partial snake (15GeV/c,  = 8) UNILAC d HESR polarized deuteron source (D. Eversheim, talk today) with interface at UNILAC ~ 1 ~ 0.1 ~ 0.8 A = 2, Z = 1,  d = ½  p  L = 0.5 · L p (per nucleon) BetaCool simulations (A. Lehrach):  d = 1/3  p possible no longitudinal d spin

20. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Deuterons (ii): a more technical problem For p=15GeV/c: protons: deuterons:  p = 0.99805  d = 0.99227 With fixed eRing length L e =577.13m and h p =h d =200:  length difference for ion ring: 3.35m ! For fixed repetition rate of eRing: By choice of unequal harmonic numbers for proton and deuteron operation one can stay with constant ring lengths of ion and electron ring (and with the rf-systems of both rings) and have collision with the maximum momentum of 15 GeV/c.

21. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz HESR / 15GeV deRing / 3.3GeV L [circumference, m]576577.126 R [bending radius, m]3025  norm /  geo [mm mrad ] < 2 / 0.13  IP [m] 0.1 r IP [mm] /  IP [mrad]0.111 / 1.12 l [bunch length, m]0.1< 0.1 n [particle / bunch 10 10 ]0.9223 I b [bunch current, mA]0.7619.1 h [bunches / ring] 173172 I [total current, A]0.1323.29 P SR [sr-Power, kW] / [kW/m]1375 / 8.8 f coll [collision freq., MHz]89.346 coll [bunch distance, m]3.3293.355  Q sc 0.1  [beam beam parameter]0.0140.0025 Luminosität [1/(cm 2 s)] (inc. 80% hour glass red.) 1.9 · 10 32 P [polarisation, %]80% Deuterons (iii) parameter set needs only 4.1MV eCool collision of unequal bunch numbers

22. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz HESR / 15GeV peRing / 3.3GeV L [circumference, m]576577.126 R [bending radius, m]3025  norm /  geo [mm mrad ] < 2 / 0.13  IP [m] 0.1 r IP [mm] /  IP [mrad]0.111 / 1.12 l [bunch length, m]0.1< 0.1 n [particle / bunch 10 10 ]3.623 I b [bunch current, mA]319.1 h [bunches / ring] 172 I [total current, A]0.5153.29 P SR [sr-Power, kW] / [kW/m]1375 / 8.8 f coll [collision freq., MHz]89.346 coll [bunch distance, m]3.3493.355  Q sc 0.1  [beam beam parameter]0.0140.010 Luminosität [1/(cm 2 s)] (inc. 80% hour glass red.) 3.8 · 10 32 P [polarisation, %]80% Deuterons (iv) parameter set for protons

23. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Helmholtz Institut Mainz (HIM) Cooperation between Mainz University ↔ GSI (Helmholtz Centre) Application in March 2009 Review in April 2009 (“strongly recommends the foundation”) Final decision on 05.06.09 Start: Summer 2009 Section: Accelerator Physics and Integrated Detectors (ACID) Resources 2 x PostDoc, 3 x PhD ( 1 x PostDoc, 1 x PhD) Tasks ENC@FAIR: IR design and detector integration, bunch formation in HESR, beam – beam  In collaboration with participating institutes: 1 st order design report (2011), Technical Design Report (2012/2013) eCool HESR/ENC: solenoid channel, beam diagnostics, upgrade 4.5MV  8.2MV sc cw demonstrator linac section for super heavy element production

24. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz Conclusion ENC is very interesting extension to FAIR Accelerator working group is established (Mainz, Bonn, Dortmund, FZJ, DESY, GSI,...) Needs fulltime manpower ! Needs more collaboration ! Main topics to deal with - spin and beam dynamics in eRing - beam dynamics in HESR bunch formation process under eCool - IR design with PANDA and spin rotators (in close collaboration with detector physicists) - beam-beam effects in ENC@FAIR case (“low energy” protons, short e - bunches) - eCool at 8.2MV and ampere currents - system integration Deuteron mode as start version (4.1MV eCool sufficient)

25. Andreas Jankowiak, Institut für Kernphysik, Johannes Gutenberg – University Mainz