ILCTA – Cryomodule Assembly Buildings

Fermilab’s Cryomodule Assembly Facility consists of two areas: MP9 and the Industrial Center Building (ICB). CAF-MP9 is a 12,000-square-foot facility which consists of a Class10-100-1000 clean room for the cavity string assembly and cold mass assembly infrastructure outside of the clean room. The Industrial Center Building is an 18,000–square-foot production floor building, which accommodates two parallel cold mass assembly areas and final assembly areas in order to achieve the ultimate throughput for the facility -- one cryomodule per month.

Inside the facility at CAF-MP9, Fermilab engineers and scientists receive chemically processed bare cavities for ILC R&D. These cavities are prepared for the vertical test in the clean room. If the test is successful, these cavities then get welded inside a helium vessel. The cavities then get dressed with a power coupler in the clean room. A tuner and magnetic shielding get added before heading off for high power radiofrequency testing in the Horizontal Test Stand. If the cavity achieves the desired acceleration gradient in the test stand it returns to the clean room to be assembled into a string of eight cavities for eventual inclusion in a cryomodule. (If the cavity fails the horizontal test, it needs to be further processed and/or high pressure rinsed.)

Technicians assembling the 3.9GHz cavity string in Fermilab’s clean room.

The string of eight cavities then gets mated with a cold mass and transported to the Industrial Center Building for final assembly. In this area, additional instrumentation is attached and the cavities are aligned. The cavity assembly is then inserted into a vacuum vessel, and the warm couplers get attached, resulting in a completed cryomodule ready for testing in the ILC Test Area that is being built at the New Muon Laboratory.

In CY2006, A large effort went into constructing the optimal clean room for ILC R&D. The 2500-square-foot clean room is divided into three sections to accommodate each stage of the labor intensive assembly process. Rated according to the number of particles per cubic foot, the clean room contains a Class 1000, Class 100 and Class 10 area. The first section, a Class 1000 Ante Clean Room, is a prep room where the cavities and other peripheral parts get submerged in ultrasonic baths and blown with ionized nitrogen to reduce the particle count to less than 10 - a critical step before entering the next stage of the assembly process.

The class 10 area, which is used to assemble the dressed cavities to form a string, has more filters and more floor perforations in it to constantly keep air flowing. Every six seconds 100% of the air in the clean room changes with approximately 90 feet per minute laminar air flow speed. While designing the clean room, Fermilab worked closely with DESY scientists and engineers, who described their ideal clean room scenario, and consultants, who specialize in building clean rooms for major corporations. Any person who enters the room must first "gown up" in special head to toe gear.

The 3.9GHz cavity string in CAF-MP9 clean room

CM2, which will be the second 1.3GHz module, is planned to be assembled at CAF starting from late CY2009. The part kit (except the 8 qualified cavities) was provided by INFN and the components arrived to FNAL in mid March 2009. FNAL engineers, scientists and technicians are currently working to prepare eight cavities that will be used for the CM2 cavity string. Cavities are currently being tested at vertical test stand in Industrial Building 1. The cavities will then be outfitted with its helium vessel at CAF-MP9. FNAL recently setup an assembly and welding facility at CAF-MP9 for cavity to helium vessel welding. After the cavities are outfitted with their helium vessel, the cavities will be processed with high pressure rinsing at ANL facility. The cold part of the power coupler will be installed and the cavity will be prepared for horizontal test at CAF-MP9 clean rooms. After 8 cavities are tested successfully, FNAL will start the assembly of CM2. CM2 as her elder sister CM1 will be used to populated FNAL ILCTA-NML facility.

FNAL engineers and scientist need to do some upgrades to CAF infrastructure in CY2010 and CY2011 for the Project-X throughout requirements. (1 module per month)

CAF -Update