Doctorate in Applied and Engineering Physics  

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Thesis Proposal for the

Doctorate Program in Applied and Engineering Physics (DAEPHYS)

Starting in the Academic Year 2016/2017


Proposal 015


Title:Development of Robust and Fail-Safe frame for Slow control infrastructure to direct dark matter search experiment Xenon1T
 
Objectives (recommended length: 2000-3000 char):
The main objective of this proposal is the development and integration of tools that ensure a robust control system in an experiment in the field of astroparticle physics detection (the dark matter direct search experiment XENON1T). The XENON1T experiment is being installed at Laboratori Nazionali del Gran Sasso (LNGS), in Italy, on its underground facility, by a consortium of more than 20 international institutions and around 130 researchers.
The control system of XENON1T was designed to be based on a framework of commercially available hardware and software tools and should interface an eclectic set of protocols and norms for signals from hundreds of sensors and instruments used to measure the most relevant physical processes of the experiment. Although this framework already provides several tools for code development (at the sensor/instrument interface), visualization and historical data recording, there are still many instrumental limitations that should be overcome in order to guarantee a reliable knowledge of the processes involved and allow a prompt intervention in case of emergency (like deviation from set-points, failure of equipment, power failure or natural hazard).
In order to achieve a robust control system some key objectives will be pursued:
• Integration of key instrumentation control like the light calibration of the detector and muon veto sensors (PMTs) and Radon detectors both in air and water shieldings.
• Design and implement a fail-safe network infrastructure. One important objective related to the security and safety of the slow control system infrastructure is related with need to guarantee the integrity of the computational infrastructure. The system that is being installed needs the inclusion of redundancy servers and the setup of a backup network connection to the outside world. The whole control system should commute between servers and networks seamlessly and with no intervention from the users or operators.
• Implement a real-time world-wide alarming notification mechanism of most of the recorded parameters according to function and sub-system.
• Create an interface mechanism to live and historical data in an open framework (compared to the closed system currently granted by the commercial solutions adopted). This enables other goals such as a web based monitoring tool for real-time monitoring regardless of computational platform or location, or, a live access from other systems (DAQ, Muon-Veto, in real time).
• Establishment of the operation state machine of the detector core. Characterization of the operation conditions of the TPC for the conditions of data taking (run, idle and maintenance) and assess deviation from normality as a veto/validation for signal analysis.
Complementary, there’s also the important goal to produce scientific/technical documentation (papers for peer reviewed journals and international conferences) that describe and analyze the developed solution.
 
Framework (recommended length: 500-2000 char):
Xenon1T is the next generation Dark Matter search experiment using 3.5 tons of liquid xenon for direct detection of Dark Matter. A dual-phase Liquid Xenon Time Projection Chamber (TPC) shielded below 1400m of rock at the Gran Sasso underground laboratory in Italy serves as both target and detector. The TPC is inside a 10m high by 9.5m diameter water Cerenkov detector serving as an active muon veto.
The experiment is currently in the commissioning phase. Its systems (such as Cryogenics, Xenon Recuperation, Purification, Distillation, Calibration, just to name a few) have been developed by dedicated workgroups, under instrumentation control guidelines to ease its integration in the main control infrastructure of the experiment (the Slow Control System). This Slow Control system is designed to use industrial process control hardware and software. The system aims to provide secure monitoring and control by collaborators, shifters and experts (different roles) at both local and remote locations. A sensitive and ultra-pure load of 3.5 tons of liquid xenon requires extreme care to guard the safety of the instrumentation and to prevent the loss of any mass of the high value xenon. To this end, the system should integrate safety mechanisms such as guarded operations, redundancy, real-time alarm notifications and be fail safe should all power be lost.
The system consists of a distributed architecture of networked local control units (programmable logics devices or PLC) with touch panels for local control and redundant central Supervisory Control and Data Acquisition (SCADA) computers. All operating parameters and their history can be stored and displayed. Also a real time alarm system in envisaged in order to deliver text messages by both email and cellular phone channels plus recorded voice over land telephone lines.
 
Tasks (recommended length: 1000-3000 char):
Considering the presented goals, it is possible to define a set of tasks:
• Virtualization of all the supervisory control servers infrastructure. The performance improvement of this procedure will ease the backup and replication of server machines (SCADA, Historian, Webservers, Alarms).
• Development of seamless commutation of the redundant network infrastructure for the control servers communication and between them and the external world. Setup of an independent monitoring and alert system for this system.
• Development of a new data path (non-proprietary) for the slow control data to allows real-time visualization of the experiment processes from remote locations for different computational platforms (fixed and mobile). This should be accomplished by creating a new interface (using OLEdb) to poll the data source of the Historian (the global repository control data).
• Development of the data exploration tools to provide the collaboration community of the experiment with the set of scripts to seamlessly collect the historical data (Historian) from the control system and integrate in their own analysis tools. Data analysis is mostly done using ROOT. A library of Historian to ROOT files must be developed for trend and stability analysis.
• Development of a real time alarm notification system able to signalize emergency situations, through several channels (wired and mobile) and to diverse targets according to the role in the experiment (shifter, developer or expert). This system should be able to deliver, in real time, configurable alarm messages upon the occurrence of alarm conditions from PLCs or SCADA. This feature is not granted, to the level that the experiment requires, by commercial solutions.
• Characterization of the detector performance, measured by direct parameter analysis or indirect (like electron life time / drift velocity after primary scintillation) for the different operation modes (run, idle, calibration) and depending on the key parameters for detector medium (temperature, pressure, levels, tilt), TPC (anode and cathode mesh grids HV) and gas/liquid xenon flow and purity. Under this characterization must also me studied the DAQ parameters (rates and pulse timings) and its dependence on the detector characterization parameters and how they affect detector performance. A fine knowledge of this will allow a better understanding of the detector response and behavior.
• Stability analysis of the main parameters of the detector, over time and according with the operation mode of the experiment (on run, filling or recuperating the xenon from the TPC, etc.). This is fundamental to validate the run data quality and in the scope of the experiment is considered vital. Due to the experimental and unprecedented nature and dimensions of the detector (3.5ton LXe TPC).
The overall results of these tasks will improve of the robustness (physical and logical) of the instrumentation control used in XENON1T experiment.
 
Research centre/lab or R&D unit hosting the thesis project:
LIBPhysUC
 
University to which the thesis project will be presented:
UC - Universidade de Coimbra
 
DAEPHYS Scientific Domain in which the project fits:
Instrumentation
 
Relation of the project to the Scientific Domains of DAEPHYS:
The current work proposal can be fully integrated in the Instrumentation field. Aspects of physical and logical of instrumentation development are encompassed in this program and the expected outcome will demonstrate that the approach of using industrial off-the-shelf instrumentation modules in a complex and experimental setup (applied to a physics experiment) can benefit from the inclusion of an additional layer of control and alert with real-time characteristics. The work plan can be divided in two stages devoted to two different aspects of the instrumentation development; the first tasks require the creation of new tools more related to the software robustness and increase of functionality; while the last two tasks of the work plan are devoted to the exploration of the developed tools to have a better knowledge of the TPC detector operation and behavior with the goal to establish its operation validity space.
 
Candidate profile:
The candidate must have a Master in Science degree in engineering (physics, computer science or electrical) and shall have a solid background in data acquisition and control systems along with a strong knowledge in high level structured programming languages and relational database concepts. Priority will be given to candidates with knowledge in network design, management and security. Candidates should speak and write fluent English.
 
Does this proposal involve more than one University?:
no
 
Synergies between the two Universities participating in the proposal:
DAEPHYS strongly encourages the presentation of thesis projects in co-supervision by researchers from two of the universities participating in the Program. In this field, explain the benefits resulting from the proposed co-supervision and the involvement of elements from the two universities, e.g. building critical mass teams, profiting from existing infrastructures or advanced equipments, profiting from expert technical know-how, etc. If the proposal involves only one University, write n/a.
(recommended length: 500-1000 char)
:
 
Does this proposal involve a company?:
no
 
Proposals involving a company:
DAEPHYS strongly encourages the presentation of thesis projects involving a company, preferably a high-tech company. These proposals have to: 1) be centered on a technological problem in which the partner company has been (or plan / would like to be) involved; 2) have a co-supervisor on the enterprise; 3) include part of the project to be carried out in the company.
(recommended length: 500-1000 char)
: NA

 

Supervisor

Name:João Manuel Rendeiro Cardoso
Institution:University of Coimbra
email:jmrcardoso@uc.pt
 
link to CV or indication of ORCID ID:
0000-0002-8832-8208

 

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