CAST-CAPP/IBS Detector Integration with the CAST Magnet

1. CAST-CAPP/IBS Detector Integration with the CAST Magnet Lino MiceliCAPP 2 Dec 2015

2. Agenda • Introduction: Lino Miceli • Cavity cooling: • A scheme proposed by Prof. Hyoungsoon Choi • Discussion • Vacuum vessel requirements and design • Martyn Davenport: MRB 2K return pipe as a possible cooling source • Discussion • Outlook and planning

3. Meeting introduction • Main topics from last meeting: • Requiring 1.8 K system temperature • New vessel (“present concept”) • Cavity cooling (including cables) • Cooling power requirements • Magnetic field shielding • Establish the need for circulators • A study to understand the consequences of a magnet quench and impact on cavity design.

4. Cooling power requirements • Main heat sources: amplifiers (inside the new vacuum vessel) and piezo actuators (inside the cold bore) • Amplifiers: Low Noise Factory LNF-LNC4_8D • Assuming factory DC power specification: 0.50 V @ 80 mA = 4 mW • 14 cavities (filling one bore with 50 cm cavities) = 56 mW • We should be safe if we plan for 500 mW • Tuning piezo actuators: Janssen Precision Engineering CLA1801-HF • Dissipation spec: 0.25 mJ / step @ 4 K. Assumed 1 mJ and 5 nm / step at a speed of 20 steps / s the cooling power requirement would be 20 mW. • Moving 10 cavity simultaneously (no need to) the cooling power requirement inside the magnet is 200 mW

5. Cooling power requirements (continued) • Antenna (coupler) piezo actuators: Janssen Precision Engineering CLA1801-HF • Assume similar figure as the tuning piezos Overall cooling power requirements for a magnet bore filled with 14, 50 cm long cavities • 0.5 W inside the amplifier vacuum vessel • 0.5 W inside the magnet bore Magnetic field shielding inside the vessel • Maximum field requirement: 100 gauss