The Bremsstrahlung radiator consists of a target ladder with several thicknesses of natural Cu of size 1.5" times 0.75". Typical radiator thicknesses are 2%, 4%, and 6%, all in radiation lengths. The Bremsstrahlung radiator is the last element in the Hall C beamline before the scattering chamber, at a distance of about 1.2 meter from the physics targets.
The target ladder can be moved in and out of the beam by use of a stepping motor. Targets are cooled with water to prevent destruction of the targets by a high current beam. Because we may use these radiator targets in conjunction with a high energy, high current beam we may produce a large amount of background in the radiator, and radiation in the parts around the radiator. For this reason the Bremsstrahlung radiator will be enclosed by a lead shield.
The only safety issue concerning the Bremsstrahlung radiator is that of induced radioactivity in the Cu targets, or more seriously, in the water used for cooling the targets. The water cooling system is a closed loop. The heart of the system is a portable welding torch water cooler. This device is kept in a tray which is intended to provide secondary containment in case of a leak. The cooling system must not be breached or drained without concurrence from the RCG. Accidental breach or spill constitutes a radiation contamination hazard. A spill control kit, capable of containing a system leak or spill, is staged in the hall next to the cooling system tray. The cooling system is located .
The Cu targets will certainly be activated in the course of an experiment. Therefore, only remove the Cu target, the target ladder, the shielding around the radiator, and/or the whole radiator system in the presence of a Radcon technician.