Superconducting Magnet, SCRF and Cryogenics Activities at VECC *, Kolkata Shekhar Mishra Rakesh Bhandari *Department of Atomic Energy, Government of India

An Experimental Setup : LAMBDA + g-Multiplicity Array + neutron TOF Array. All detectors in the above setup have been designed & fabricated at VECC. Neutron TOF detectors  Multiplicity Filter Large Area Modular BaF 2 Detector Array (LAMBDA) The 224 cm Variable Energy Cyclotron (VEC) is being operated as a national facility at VECC. The accelerator operates round- the-clock for research experiments. VEC

Superconducting Cyclotron at VECC  K bend =520  To accelerate heavy ion beams  Energy  80 MeV/nucleon for light ions  ~10 MeV/nucleon for heavy ions  Radiofrequency system  9-27 MHz  80 kV maximum dee voltage  Superconducting magnet  Average magnetic field ~ 5 Tesla  80 ton magnet iron  12.5 ton cryostat + coils

Superconducting coil winding in progress at VECC Completed coil

Cryostat assembly and thermal analysis

CRYOGENIC PLANTS AT VECC Helial 50 a) Refrigeration capacity: 4.5 K or better b) Liquefaction capacity: 100 litres/hr Helial 2000 a) Refrigeration capacity: 4.5 K or better b) Liquefaction capacity: 85 litres/hr  A valve box with seven valves can control the liquid and gas flow from one or the other refrigerator to the cryogenic systems of the superconducting cyclotron.  It is possible to balance some liquid from one dewar to the other : improves the magnet LHe flow behaviour

First beam was accelerated in the superconducting cyclotron on August 25, 2009: Utilization for experiments will start in Several experimental facilities are ready. 7 Some experimental facilities developed at VECC for experiments with the superconducting cyclotron and VEC

8 Rare Ion Beam (RIB) project at VECC Schematic Layout RIB project site Present Status  Ion-beams of Oxygen, Argon, Iron, Carbon, Nitrogen, Helium (stable isotopes) with beam energy up to 287 keV/u available from the facility  Commissioned 1 st RFQ in the country. Second, RFQ commissioned in June Fully indigenous development.  Linac-1 & Linac-2 installed, Linac-3 installation underway. Linac 4-6 designed & being ordered. Final energy will be 1.3 MeV/u.  Ion-beams from the facility are being used for material science experiments.  Superconducting Electron Linac development in collaboration with TRIUMF Canada – 1 st phase : 10 MeV Injector Cryo Module 1.3 MeV/u Thick-target ECR IS 100 keV/u 1.7 keV/u LINACs 4-6 VECC- TRIUMF 184 keV/u RIB 415 keV/u We are here Separator RFQ LINAC1 LINAC2, K130 Cyclotron e-Linac 50 MeV, 2mA

ECR 3.4m RFQ 1.7 keV/u Target- 1+ ion source 1.7m RFQ Linac-1 Linac-2 Linac-3 Rebun-1 Rebun-2 29 keV/u 99 keV/u 287 keV/u 414 keV/u 184 keV/u K130 Cyclotron vault Primary beam Rare Ion Beam (RIB) project at VECC : current status Towards new building Existing beam-line Dedicated material Science beam-line Linac-1 RFQ ECR Recent photo of RIB site We are here

Production of neutron-rich RIB using photo-fission production route e-linac Uranium e-  ISOL type RIB facility RIB UC 2 target 50 MeV, 100 kW Fe Ni Kr Sn Xe Dy N Z RIB production rates in 238 U target for a total photo-fission rate of /s Source SPIRAL II electron option PDS Kr – 92 Kr 140 Xe 132 Sn

Schematic Layout of SC Electron Linac Thermionic gun: 100 keV; 10 mA 650 MHz NC buncher 1 st multi-cell cavity; 10 MV/m, 1.3 GHz Four 9-cell cavities, 10 MV/m each; 1.3 GHz; Q= MeV 100kW 10MeV Gun Injector Cryo Module Driver ~15m Bun SC capture VECC-TRIUMF MOU ( ) Phase 1 Status of ICM development Beam dynamics design completed, Conceptual mechanical design of Cryostat completed. Detailed mechanical design underway. Prototype Nb cavities made at PAVAC (local industry associated with Triumf) ICM

Beam dynamics design for the electron linac : Preliminary Input beam parameters : Beam energy = 100 keV Energy spread = ± 1.0 keV Beam current = 10 mA Bunch length = 170 ps FWHM  MHz i.e ±20  Charge in each bunch = 16 pC Normalized emittance (ε) =30 pi. mm. mrad Desired output beam parameters : Beam energy = 50 MeV Energy spread = < 1% Beam current = 10 mA Bunch length = <30 ps FWHM  ± MHz Normalized emittance (ε) =100 pi. mm. mrad Output beam parameters from first TRACK simulation Beam energy = MeV Energy spread = ± 0.06% Bunch length = ±6.3  (± 13.5 ps) Normalized emittance (ε) =56  mm.mrad Maximum beam size x/y = ±1.3 mm preliminary

Detailed mechanical engineering design of the cryostat for the ICM has been started

Length of a half-cell of the cavity =L/2 =70 mm. Iris radius = R iris = 50.4 mm. Dome (equator) radius = D/2 = 188.2mm. Equator ellipse ratio = A/B = 45 mm/47 mm. Iris ellipse ratio = a/b = 12.5 mm/15 mm. E-field profile along the axis High  SCRF cavities for p- linac Frequency: MHz

Bead-pull measurement -- special technique adopted Using Phase-shift technique instead of frequency-shift In manufacturing or tuning multi-cell cavity, it is required to investigate the field profile inside the cavity The Field can be sampled by introducing a perturbing object and measuring its change in f 0 The object must be very small so that the field does not vary significantly over its largest linear dimension: it is a perturbation method Phase deviation is much easier to observe than frequency change especially for small perturbation. PHASE (Degrees)IMPEDANCE

 Preliminary design completed 2.6 m long 1.35 m dia. LHe vessel 1.4 m Long 0.72 m dia. Static losses (without RF): 15W heat load RF losses 9 ): 15W VERTICAL TEST CRYOSTAT

Thank you all!