Helium Cryogenic System

TARLA’s helium-based cryogenic system enables the operation of superconducting RF (SRF) cavities at ~2 Kelvin, ensuring efficiency and stability.

🔧 Technical Components & Capacity

• Compressor Unit: Two screw-type helium compressors, ~140 kW each
• Cold Box 1 (CB1): Produces ~45 L/h of liquid helium (LHe I) at ~4.5 K without LN₂ pre-cooling
• Cold Box 2 (CB2): Distributes helium to cryomodules and lowers temperature to ~1.8 K using vacuum pumps and heat exchangers; ~180 W cooling with LN₂, or 40 W without
• Storage Tank: 1000 L liquid helium tank
• Transfer Lines: Vacuum-insulated lines deliver liquid helium to cryomodules
• Oil Removal Unit: Filters moisture, oil, and oxygen impurities using molecular sieves and activated carbon

⚙ Operation and Control

• Fully automated SCADA-based central control
• Real-time monitoring of pressure, temperature, and flow; alarm systems integrated
• Redundant design implemented in critical subsystems

♻ Sustainability

• Closed-loop recovery and purification ensures >90% helium reuse
• Reduces operational cost and supports long-term environmental sustainability

RF Systems

The accelerator infrastructure heavily relies on high-power and low-level RF systems. High-power RF (HPRF) modules deliver RF energy to superconducting and normal conducting cavities. The schematic structure of the RF system is illustrated in the figure.

At TARLA, a 1 mA electron beam is accelerated to 40 MeV using superconducting structures operating at 10 MV/m. High power RF system includes four TESLA-type superconducting cavities powered by solid-state RF amplifiers, each capable of 18 kW output. The injector features two normal conducting RF cavities.

The Low-Level RF (LLRF) system regulates the amplitude and frequency of RF signals delivered to the cavities and synchronizes beam-RF interaction. LLRF supports:

• A 260 MHz subharmonic buncher (SHB)
• A 1.3 GHz fundamental buncher (FB)
• Four 1.3 GHz TESLA superconducting cavities

The LLRF system is fully digital and includes six RF station controllers, each integrated with mechanical tuner control units. Additional modules such as the Local Oscillator Generation Module (LOGM) and Drift Compensation Module (DCM) are essential for signal generation and drift correction.