CCC Project at GSI- Update

1. CCC Project at GSI- Update Febin Kurian GSI Helmholtzzentrum für Schwerionenforschung Germany

2. Contents • Highlights of the CCC at GSI – from the past • Beam current measurement with CCC – Spring 2014 • Measurements planned for September 2014 • Conceptual schematic of the new CCC system • Some hints for a new cryostat design

3. GSI-CCC Cryostat: First Concept • Possibility of test measurements offline and also within the beam line. • Possibility of complete and easy dismantling of the cryostat and the equipment therein • Low liquid helium consumption - Manual filling of LHe is difficult especially when installed in the beam line – one filling should be enough for complete experimental session. • Should have a more or less fixed cycle time including (cooling down- experiments- warming up)

4. Existing CCC system at GSI 658 mm 1200 mm 352 mm 100 mm 381 mm 710 mm

5. GSI Facility CCC installation location

6. Beam current measurements with CCC Plan of the measurement • Characteristics of the newly installed SQUID sensor system and electronics • Noise figure of the CCC system • Vibration analysis of the experimental set up • Measurement of the beam current • Comparison of the measured currents with a different system (in our case, Secondary Electron Monitor)

7. Supracon SQUID + Magnicon Electronics I-V Characteristics • Transfer co-efficient of the SQUID, • Current needed in the feedback coil to produce one ; () = = 10.66 µA • Gs, Gain of the SQUID • With a Gain bandwidth product = 0.38GHz, the system bandwidth, Gs. GBP For the best settings, Rf@FLL was set at 30 KΩ Amplification of the SQUID given - 2000 200mv/div 1µA/div V-ɸ Characteristics 200mv/div 50mv/div

8. Current Calibration CCC- pickup coil Low pass filter- Cut off frequency = 170 Hz 50 nA Test pulse signal measured by CCC (noise floor – 2 nA)

9. Noise Spectrum

10. Current Calibration Curve Voltage- Current conversion factor=74.2 nA/V

11. Current Measurement Scheme Measurement room Oscilloscope/FFT DCCT Amp. T,P,L SQUID Control Current Source Diff. Amplifier SEM H.V CCC SIS18 SQUID Al foils Femto DHPCA 100 transimpedance amplifier. GM cooler unit Femto Amp control pc- Remote access

12. Current Measurement-1 Example of a raw output signal shows the beam current of about 3E9 particles of Ni26+with energy of 600 MeV extracted from SIS18 over 1 second (Mean current – 12.5 nA) • Output signal contains, • Signal from the DCCT installed in SIS 18 • CCC differential output -- blue and red • SEM signal

13. Current Measurement-2 Beam current signal by 7E8 particles of Ni26+with energy of 600 MeV extracted from SIS18 over 500 millisecond (Mean current – 5.5 nA)

14. Current Measurement-3 Smallest signal measured by CCC of 2.5E8 particles of Ni26+(Mean current – 1.9 nA) at 600 MeV extracted over 500 millisecond

15. Current measurement-CCC and SEM DCCT, CCC and SEM signals Comparison of the spill structures given by CCC and SEM when measuring the current of 5E9 particles extracted over 64 ms giving an average current of 210 nA

16. Current Estimation from plots CCC • The differential output voltages signals C2 and C3 are combined by the equation • From this output voltage, the current is estimated by A- Area of the integral (Baseline corrected) SEM • The current produced by the secondary electron, The term is estimated to be 43.7 from the “SRIM” program Integral of the spill gives ,

17. Current measurements with CCC and SEM-1 In Smaller range SEM result is shown without a multiplication factor to obtain equivalent current (Presently used factor shows discrepancies with the current values measured by CCC)

18. Special Conditions • Presence of “Anti-Alias filter” • SQUID signal is filtered with a low pass filter at the magnicon amplifier with cut-off frequency of 10KHz • Optically isolated differential amplifier • Output amplification of 10: 2 differential • Differential output • Cut-off frequency 200 KHz • SEM- Bandwidth depends on amplification factor given at the femto amplifier - 220 kHz at 108 to 200 MHz at 103.

19. Measurement planned for Sept. 2014 • Measurement over wider bandwidth (without the filter at the Magnicon electronics) • More measurements on the intrinsic current resolution of the CCC. • Wider range of the beam current/ extraction time • More set of SQUID adjustment – Rf@FLL ,GBP combinations • More measurements on the zero drift • SEM calibration and comparison with CCC

20. Conceptual design of the new CCC-1 Some boundary conditions • Limited space available in the beam line for running and more importantly for any repair works once installed. • Horizontal design – More stable and compact compared to the vertical solution • All the components in the system should be as reachable as possible for any dismantling/repair works and following cleaning up. • The system should as independent from the beam line as possible – CCC should not influence beam/other experiments nearby. • All installation locations may not be accessible when beam line is in operation – complete remote operation should be foreseen. • Any thermal fluctuation/ pressure difference in the cryostat will affect the SQUID measurements – Hence the system should be as “quiet” as possible.

21. Conceptual design of the new CCC-2 • Isolation vacuum • Disturbing the accelerator vacuum – consequences : CCC is like a cryo-pump when cold -- During warming up, release of several types of gases condensed on the cold CCC • Venting and hence any modifications is restricted by the beam line vacuum conditions. • Constant thermal load by radiation onto the cryostat from the beam tube – long “warm-hole” is unavoidable without isolation vacuum. • With isolation vacuum, one can do a lot more studies during test measurements (more realistic simulation of beam currents).

22. LHe liquefaction plants LHeP18 PT410 GM Based GWR-ATL Liquefaction unit

23. Challenges with Re-cooling systems • Purity of the Helium boil-off • Mechanical isolation of the CCC cryostat from the cryo-cooler • Thermal instabilities causes drastic zero drifts in the SQUID signal • Installation and operation space availability in all beam line

24. New CCC Concept Mag. shield incl. pickup coil isolation vacuum chamber Radiation shield Cooling- cold helium boil-off LHe cryostat Bellow – isolation vacuum Bellow – LHe cryostat SQUID signal feedthrough Ceramic spacer Suspension (3) Mag. shield Suspension (3) LHe cryostat Support - Mag. shield Vacuum connection SQUID sensor

26. 160 mm 550 mm 435 mm 657 mm 1000 mm

27. CCC Installed in HTP

28. Thanks for your attention