EXL NESR and In-Ring Spectrometer Status Helmut Weick

1. EXL NESR and In-Ring Spectrometer Status Helmut Weick WG: KVI, TU München, GSI, U. Teheran, U. Uppsala EXL / R3B collaboration meeting Darmstadt, 17. Oct 2007 • Overall Storage Ring Layout • Modifications of NESR Arcs • What to Detect ? • Tests in ESR • Resources

2. Ring Layout Super-FRS: Production, Separation CR: Bunch rotation Stochastic cooling at 740 MeV/u also for separation Direct transfer line from SIS-18 or Super-FRS to NESR RESR: Deceleration if needed down to 100 MeV/u NESR: Cooling, accumulation, measuring

3. Magnets of Storage Rings • All storage rings will have normal conducting magnets. • Based on study by Spanish consortium. + Easy design and faster construction • Power consumption higher but RESR / NESR do not run all of the time and need sometimes fast ramping • Decision not so obvious for CR, no common development with Super-FRS anymore.

4. NESR, Building 8

5. NESR Floor Plan status 15.08.2007

6. NESR Floor Plan status 15.08.2007

7. NESR redesign (only arcs) In NESR-33(57) magnets don’t fit in, nor do detectors. NESR-60, redesign gives more space with one quadrupole less. NESR-64 for better chromaticity correction, but reduced transmission directly to detectors.

8. Dynamic Aperture Dp/p=-1.5% Dp/p=+1.5% EXL: Dp/p only ±0.3%, but narrow aperture for vacuum separation Ions starting at what region of the aperture are still stored? Dynamic aperture is defined only by the shape of the magnetic fields disregarding the geometric aperture. Nonlinearities reduce dynamic aperture, require correction. Dynamic aperture should be larger than geometric aperture,even with a safety margin as we have only simulations so far. NESR61(64)Diego Obrador Campos In case ofNESR60 no dynamic acceptane for shifted momentum.

9. Comparison of Ring Spectrometer Optics NESR-60 NESR 60  64 • + larger momentum acceptance • with chromaticity correction. • More HI can be stored after reaction, (good for AIC). • - Transmission to detectors behind dipoles only half. • - Image plane for momentum measurement inside dipole. (red dashed line) NESR-64

10. Detectors between dipoles Mounting of detector pockets can be difficult. Suggestion: one vacuum chamber over two or three dipoles.

11. Resolution with Scraping For separation of contaminants (or even isomeres ?)

12. What do we want from the Ring Spectrometer ? • Coincidence of heavy ion with light recoil is needed to clean up the light recoil distribution and make it useful. • To provide start time for ToF measurement vs. light recoil • For identification (DE, Br(x), …) Reactions with changed mass or charge • But do we need the precise momentum measurements in the image plane ? • Does tracking help for improved resolution? or is it only feasible in a small acceptance bite? Almost same slide as in 2006!  Big question, request to simulation

13. What to Consider in Simulation • Simulation must combine light recoil and heavy ion. Physics information is mainly from light recoil! • Geometrical correlation: Heavy ion acceptance is limited by dipole gap. Light recoil detection is also hindered by gas target in vertical direction. • What segmentation is useful for ring-spectrometer detectors? • Simulation must be done with good overview over many reactions (see table B5 of TP).

14. D1 D2 D3 D4 Detector Positions Detector for large angles in front of dipoles with a hole for the stored beam.

15. New Detector in ESR

16. New Detector in ESRDrives are being prepared at KVI

17. Tagging Detector in ESR Beam with divergence of 10 mrad transformed from target to detector plane 7.4 m behind target. Position distribution for

18. SimulationMasoud Mahjour-Shafiei U Teheran

19. Which Detectors ?NESR and Test in ESR Segmented Si detectors as described in TP / wire chambers. High efficiency for coincidence needed. -> At least one detector very close to circulating beam (a few mm), diamond? At some positions behind dipoles high count rates from atomic charge exchange (up to 106-107/s) -> Setup has to be flexible for different reactions. But detector positions have to be fixed, pockets and vacuum sluices have to be installed. Who?KVI, TUM, GSI also for ILIMA, ELISe, AIC, SPARC

20. Should we have a detector in UHV ? + No pocket  much smaller inactive part of detector- Only UHV compatible materials (pure Si, glas, diamond)- Requires separate UHV chamber with gate valve for maintenance.- Maintenance is difficult.- Problem of cabling -> only possible for a few channels- Tails of the beam may be dumped on detector or detector will be hit due to wrong operation.  Lifetime of the detector may be very limited. Conclusion: We should try it ! An example is the ToF detector for mass measurements.But it is used at very low intensities only (~10 ions in the ring). Possible hybrid? Thin foil separating UHV and HV of pocket with very thin windows.

21. Status of Funding and Manpower Contract GSI-KVI: Work packages on this topic: N-4: Test measurements at ESR N-2: In-ring detectors of NESR (N-1: Slow control of Data Acquisition NUSTAR) N4 +N2 -> 2.5+0.8 FTEs in 2007. Investments have to be asked for separately. BMBF R&D phase:May be extended into 2008. But with present GSI financing problem it may mean, that bills from this year are paid only in 2008 (EXL target chamber). ~2.3 FTEs at GSI for (EXL, ELISe, ILIMA, and AIC). Later FAIR project money is counted. EU:EXL JRA runs out! Simulation JRA proposal for ENSA in FP7.

22. Costs: In money matrix so far only covered by GSI and TU Munich.

23. Time schedule for FAIRas of beginning this year Order should stay (last info from STI):Start version of FAIR defined by promised internationalcontributions, times four by Germany. Sum by 7th of November is less than FBTR cost book. Construction start may be delayed.