CCC Project at GSI Update Febin Kurian GSI

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

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

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)

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

GSI Facility CCC installation location

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)

Supracon SQUID + Magnicon Electronics I-V Characteristics 200 mv/div • 1µA/div 200 mv/div V-ɸ Characteristics 50 mv/div

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

Noise Spectrum

Current Calibration Curve Voltage- Current conversion factor=74. 2 n. A/V

Current Measurement Scheme Measurement room DCCT Amp. Diff. Amplifier SIS 18 SQUID Control Current Source Oscilloscope/FFT T, P, L CCC SQUID SEM H. V Al foils Femto DHPCA 100 transimpedance amplifier. GM cooler unit Femto Amp control pc- Remote

Current Measurement-1 Example of a raw output signal shows the beam current of about 3 E 9 particles of Ni 26+ energy of 600 Me. V extracted from SIS 18 over 1 second (Mean current – 12. 5 n. A) Output signal contains, • Signal from the DCCT installed in SIS 18 • CCC differential output -- blue and red • SEM signal

Current Measurement-2 Beam current signal by 7 E 8 particles of Ni 26+ with energy of 600 Me. V extracted from SIS 18 over 500 millisecond (Mean current – 5. 5 n. A)

Current Measurement-3 Smallest signal measured by CCC of 2. 5 E 8 particles of Ni 26+ (Mean current – 1. 9 n at 600 Me. V extracted over 500 millisecond

Current measurement-CCC and SEM DCCT, CCC and SEM signals Comparison of the spill structures given by CCC and SEM when measuring the curr 5 E 9 particles extracted over 64 ms giving an average current of 210 n. A

Current Estimation from plots •

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)

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 10 KHz • 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 k. Hz at 108 to 200 MHz at 103.

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

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.

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).

LHe liquefaction plants LHe. P 18 PT 410 GM Based GWR-ATL Liquefaction unit

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

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

160 mm 435 mm 657 mm 1000 mm 550 mm

CCC Installed in HTP

Thanks for your attention