Studentship overview

Context of the project:

Radiation tolerant planar silicon sensors are being developed for the LHC luminosity upgrade within the framework of ATLAS, CMS and RD50. Planar silicon sensors with n-implant readout (n-in-n and n-in-p sensors) offer a radiation tolerance well beyond that predicted by simple models. The existing models were built on data were based largely  on p-in-n sensors (as implemented in the present ATLAS and CMS trackers) and the supporting measurements were mainly performed at lower radiation levels up to some 1014 neq/cm2; these models did not properly parameterize the behavior of n-implant sensors. The measured high radiation tolerance of n-in-p sensors now makes them the most likely technology choice for the ATLAS tracker upgrade. The RD50 collaboration demonstrated that the high radiation tolerance is based partly on charge multiplication processes. However, the underlying mechanisms are not yet fully understood. Further studies aiming to clarify the origin of this effect are required. Central to these studies will be the question of if the sensor structure or the sensor material can be modified in such a way as to further improve the radiation tolerance.

The Department of Physics of the University of Liverpool hosts JIF financed Liverpool Semiconductor Detector Centre (LSDC) that delivered both the ATLAS End Cap-C array and the LHCb Vertex Locator (VELO) for the CERN Large Hadron Collider (LHC) in Geneva (CH). The group performed substantial contribution to the recent discoveries at the LHC in ATLAS and LHCb. The High Energy Physics group has a long tradition in silicon based instrumentation. Liverpool is a major player in silicon detector R&D for high energy physics tracking applications.

The CERN/RD50 collaboration is an R&D project aiming to the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements of the almost tenfold upgrade of the luminosity of the LHC (HL-LHC). RD50 counts a total of 261 members with 48 participating institutes from different countries.

PhD project:

The proposed PhD project will focus on the characterization and development of silicon sensors with modified junction profiles that exploit the charge multiplication process after high levels of irradiation. The corresponding sensors are partly already available within the RD50 project and are partly in the design phase (Sensors with deep implants and trenched implants). The student will participate in the irradiation experiments of these sensors with different type of particles and then conduct an in-depth characterization campaign using techniques as: CV/IV, Edge-TCT, CCE measurements with Alibava Systems and long term annealing studies. It is also foreseen to perform test beams depending on the availability of test beams in the period of the thesis work.

Supervising staff

Implementation and supervision:

The supervision will be shared between the Liverpool University (Dr. Gianluigi Casse) and CERN (Dr. Michael Moll), the two co-spokespersons of RD50. The student will spend 1 year at CERN for experimental work in the framework of the CERN-RD50 collaboration.

Funding

£13,590 pa Stipend £13,590 pa Stipend

Applying

Closing date for receipt of applications: 15 September 2012

Apply online at: http://www.liv.ac.uk/study/postgraduate/applying/online.htm

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