Status of the External Solenoidal Spectrometer for the TSR

1. Why an external spectrometer? • Solenoidal spectrometer • Baseline design parameters • Current status Status of the External Solenoidal Spectrometer for the TSR Robert Page

2. External Spectrometer for the TSR

3. Why an External Spectrometer? “The superior properties of the cooled extracted beam from the TSR compared to the direct beam from HIE-ISOLDE ... will be of benefit to many classes of external spectrometers that can exploit these qualities.”

4. Why an External Spectrometer?

5. What external spectrometer options? T-REX + Miniball GASPARD Active target Solenoidal spectrometer

6. Solenoidal spectrometer concept vlab v0 θlab θcm z Vcm CM Angle: CM Energy:

7. HELIOS at Argonne 24 Si PSDs 12 mm × 56 mm × 0.7 mm 9 mm × 50.5 mm active area square 23 mm × 710 mm 340 mm active length J.C. Lighthall et al.,NIM A622 (2010) 97

8. “ISOL-SRS” grant awarded!

9. “ISOL-SRS” grant STFC funding for • Detector array for internal spectrometer • External solenoidal spectrometer • Total project costs awarded, including manpower, is £4.8M • £3.2M “new money” mostly for materials Not funded: • Gas-jet target for internal spectrometer • Universities of Aarhus and Lund seeking funding • Solenoidal magnet

10. Baseline Design • Hexagonal hollow array of DSSDs • Overall Si length  0.5 m • (easily upgraded with extra modules) • Compact design to minimise distance from interaction point to axis • 1 mm thick silicon stops • 12 MeV protons • 17 MeV deuterons • 20 MeV tritons… • 1mm pitch in z • 1mm pitch in x – allows better axis crossing point z estimate • Overall active area >80% • Cooled to -20℃ • ASIC readout

11. Acceptance Simulations GEANT4 simulations by M. Labiche

12. Q-value resolution EXTERNAL SPECTROMETER: d(24Ne,p)25Ne @ 10 MeV/u HIE-ISOLDE beam: 38 keV Cooled TSR beam: 22 keV Calculations by P.A. Butler

13. Solenoidal Spectrometer for the TSR Install at CERN 1st quarter of 2019 LS2 2019-20 (if delayed 1 year) Exploit with HIE beams 2020-23 Exploit with TSR beams from 2023

14. Current Status • UK STFC grant started 2015 • Realistic layouts for ASICs, etc. • Defining final parameters for Si DSSDs • ASIC delivery now due for R3B

15. MRI magnet: Oxford OR66 • 4T, ActiveShield technology MRI magnet available (type OR66) • Large bore of up to 90 cm diameter, ~2m long • Magnet comes with power supply, cold-head and compressor, and other equipment and should be operational • Installation requires cool-down (6500 litres of LHe, ramping and shimming (passive and active shimming) • Specifications: Brisbane = HeliOz magnet?!

16. Magnet funding opportunity!

17. Conclusions • Funding awarded for external spectrometer • Preliminary design work is underway • Efforts to obtain ex-MRI magnet continuing Thanks to: Peter Butler, Sean Freeman, Marc Labiche, Ian Lazarus, Alan Grant, Mike Cordwell, Dave Seddon, Jim Thornhill, Dave Wells, John Simpson, Dave Jenkins, …

19. Why a solenoidal spectrometer? vlab v0 θlab θcm z Vcm CM Energy: CM Angle:

20. OR66 magnet fringe field Space allocation for magnet assumed to be 10 x 10m

21. Energy Resolution 22 – 55 keV FWHM (protons) J.C. Lighthall et al.,NIM A622 (2010) 97

22. Position Resolution 5 MeV p + 12C 0.5 mm FWHM 2 MeV p + 12C 1.2 mm FWHM slit width 0.5 mm J.C. Lighthall et al.,NIM A622 (2010) 97

23. General Considerations • Detectors close to axis – t.o.f.  cyclotron period • Central hole for beam • Best possible energy resolution • Highest possible efficiency • Good position resolution • Good timing resolution • Flexibility – different configurations • Operation within magnetic field • Cooling of detectors • …

24. Operation in magnetic fields? “Dangerous mechanical resonances exist which can lead to the breaking of bond wires if time varying currents are passed through them in a magnetic field.” T.J. Barber et al., NIM A538 (2005) 442

25. Si operation in magnetic fields? B = 1 T