Particle Detectors or Shields

Yesterday I published a document in the ARROW@DIT archive with the title ‘A Suggested Building Block Geometry Without Continuous Radial Joints of Possible Relevance for Particle Detectors’. It is a hand-written document that I wrote while on holidays in Germany in 2009. It is available at this link http://arrow.dit.ie/engschmecart/16/.

Particle detectors are used by physicists, for example at the CERN large hadron collider. A particle detector often requires or involves a material that can slow down particles or block particles or make particles change into other particles such as photons of light that can be readily detected. Often the particles, which may be a mixture of many different types, are emitted radially from a source region of activity, e.g. a region where hadrons collide. Particle might also arrive radially, as is the case with cosmic rays. In some cases particle detectors require a huge and very massive body of material surrounding the source region, or surrounding a detecting instrument. The material could be described as shield material, or absorbing material or moderating material. It could be steel or lead or titanium, for instance, or it could be a liquid like water. Ideally the shield material might be required in the form of a thick spherical shell. In some cases, e.g. if the source region were linear, it might be required in the form of a thick cylinder.

A difficulty with thick spherical shells and thick cylinders is that they cannot be built up from identical building blocks like cubes. Of course, spheres or cylinders can be approximated by a large number of cubes. However, the symmetry of the cube does not match very well with the symmetry required for thick spherical shells or thick cylinders.

Experiments, like engineering projects generally, are based on compromise. When physicists build particle detectors they need to fit sensors and various bits-and-pieces, including wires or light guides, into the volume of space that contains the shield material. In some cases the shield building blocks might require cladding of some sort or an integrated support frame. If shield blocks with cladding or structural elements are fitted together there may be planes between the blocks where the shielding effect is compromised, which in turn might compromise the measurements.

The concept described in the document is a building block configuration that may offer benefits and advantages for certain types of particle detectors or particle shields. Potential applications might include the construction of particle detectors or shields in outer space.

A somewhat related document entitled ‘An Exploration of a Discrete Rhombohedral Lattice; of Possible Engineering or Physical Relevance’ is available at http://arrow.dit.ie/engschmeccon/2/. A few years ago I spend a lot of time working with the geometry of the rhombohedral lattice and modelling it mathematically.