Ladder with Ultra-Low Material Embedding
:Pixelated Ladder with Ultra-Low Material Embedding
This study is motivated by the development of a vertex detector for a future linear collider - International Linear Collider (ILC). The ILC is a planned linear electron-positron collider to complement physics discoveries at the Large Hadron Collider (LHC) by making precision measurements up to centre of mass energies of 1TeV.
The large energy of beam bunches of electrons and positrons causes a large background of electron-positron pairs produced by beamstrahlung radiation. The combination of this beamstrahlung background and the fact that beam bunches will be 337ns apart forces the requirement of a light weight, high precision inner detector system with inter bunch-train time slicing in order to accurately measure properties such as quark charge sign.
PLUME ladder design;
The ladder is composed of two kapton-metal flex cables supported by a layer of SiC foam.
Each flex is mounted with 6 thinned(~50 µm) Mimosa-26 sensors.
The active area (sensor area) is approximately 1x12cm² - the material is most abundant here.
The ladder has been designed to have extremely low material budget. Vertex detectors are designed to measure vertices of primary, secondary and possibly even tertiary vertices. Several detector properties (such as resolution, geometry and material) can be described together by a more general parameter - the impact resolution - which is a function of the multiple scattering cross section. It is therefore a trade off between lowering the material budget of the ladder whilst maintaining mechanical stability, resolution and fast read-out. The double-sided ladder design has several possible benefits. The distance between upper and lower sensor is approximately 2mm and makes it possible to add a mini-vector between associated pixel hits on each sensor which enhances resolution. There is also the possibility of using slightly different sensor set-ups on the upper and lower layers - one layer focussing on spatial resolution and the other on time resolution.
Oxford is currently concentrating on the design of the kapton-metal flex and the testing of its electronic properties as well as investigating the alignment of the ladders.
Testing ladder prototypes in conditions similar to that of the real experiment is crucial in understanding how well the resolution of the detectors will hold up.
In Oxford we are currently assembling the ladder box (Alignment Investigation Device - AID) to determine how well pairs of over-lapping ladders function when subject to showers of charged particles.
A physics study which would require the type of vertex detection - quark charge determination - that PLUME is designed for can be found here. This study looks at the forward-backward asymmetry produced in top/anti-top quark pair production at the ILC.
An outline of the PLUME project including progress and future plans can be found here.
2010 Jan 30: PCB version of the flex
*IK Frankfurt(CBM @ Fair vertex det.)
*LBNI. Berkeley(STAR @ RHIC vertex det.)
Updated 13 February 2012by Andrei Nomerotski and Rhorry Gauld