Summer Placement Programme 2016

Oxford Particle Physics is running a summer placement programme for undergraduate physics students. We anticipate taking about 8-10 students. Priority will be given to students in their second year and above. Unfortunately we cannot take students from outside the EU unless you already have a work permit.
Students will work with a supervisor in the department, usually a postdoctoral researcher or lecturer, on a self-contained project. Students are encouraged to take part in department life, joining researchers for coffee and discussions.
The projects run for typically 8 Weeks during the Oxford summer vacation. Students will be paid a subsistence of £230.00 per week. The project is full-time but hours can be discussed with your supervisor.

Applying

You should email a one-page-only application, in pdf format, to Sue Geddes (s.geddes@physics.ox.ac.uk) by Sunday of 1st week, 24 April 2016. Students should ask for a short academic reference letter to be emailed by the same date. Offers will be made in mid May 2016.
On your 1-page application you should tell us why you are interested in the programme and which project(s) most interest you. Also include your contact details, your year and course, and contact details (including email) of your academic referee. Please also mention any computer programming experience and any previous research experience that you have had.
You are welcome to informally contact the supervisor(s) to find out more details about the projects that interest you. For any administrative issues, contact Sue Geddes (sue.geddes@physics.ox.ac.uk).

Projects

Here are some of the proposed projects. They span a range of our interests. Most of the research activity involves analytic and computing work.

CMOS sensors for the ATLAS upgrade (two positions)

Position #1 Dr Todd Huffman (todd.huffman@physics.ox.ac.uk)
Duration: 8 weeks
Position #2 Professor Daniela Bortoletto (daniela.bortoletto@physics.ox.ac.uk) & Professor Ian Shipsey (ian.shipsey@physics.ox.ac.uk)
Duration: 8 weeks

The ATLAS group has quite a number of CMOS sensors that will need to be tested and understood. CMOS sensors have the basic amplifier and data processing electronics built into the sensor itself and all of it laid out on the same silicon wafer. We are evaluating them to see if they can be suitable to use in the next ATLAS upgrade planned for 2022. A student need have only minimal programming experience but of course, anything might be useful. Much of the work will take place in the new OPMD clean room in the Hooke Building.

Understanding Pixel Module performance for the ATLAS upgrade

Professor Daniela Bortoletto (daniela.bortoletto@physics.ox.ac.uk) & Professor Ian Shipsey (ian.shipsey@physics.ox.ac.uk)
Duration: 8 weeks

The ATLAS group will be assembling pixel sensors for use in the ATLAS upgrade and must understand process control and the system level issues and performance of the full pixel sensors that are made in the OPMD facility in the Hooke building. The project involves helping with the construction and testing of pixel sensors in order to develop the capability to produce them en-masse for the ATLAS upgrade project. These sensors would be used in the LHC for the 2022 upgrade to the ATLAS detector.

Probing naturalness with Higgs measurements

Dr Chris Hays (chris.hays@physics.ox.ac.uk)
Duration: 8 weeks

This project will focus on Higgs measurements sensitive to new particles that can solve the naturalness problem (i.e., why the Higgs mass is at the electroweak scale when loop corrections should give it a much larger mass). Using supersymmetry as a concrete example, Monte Carlo samples will be generated for a range of the allowed parameter space.
The Monte Carlo will then be used to identify the distributions most affected by the presence of the stop quark loop in Higgs boson production (i.e., the loop that solves the naturalness problem in supersymmetry).

High Speed Electrical Tapes for the ATLAS Upgrade

Professor Tony Weidberg (tony.weidberg@physics.ox.ac.uk)
Duration: 8 weeks

This project is on development of the electrical readout for the ATLAS strip tracker. For the high luminosity upgrade of the LHC we are designing an all silicon tracking detector that can work at an order of magnitude higher data rates. In Oxford we have been developing Cu/kapton electrical tapes to transfer all the data from the silicon modules to a board which multiplexes the data and converts it into optical signals. The tape also transmits high speed clock and control lines to the silicon modules. In addition the tape will provide all the low voltage and high voltage power to the modules. It is therefore essential to be able to fully test these tapes during production. We have developed a robotic tape tester which can test for open and short circuits for all connections. This project will develop the software that controls the tape testing robot. In particular it will determine the best way to upload data to the Database and how to download test data from the Database. Tools for performing statistical analysis of the data need to be developed. In addition the issue of the insulation quality at 500V needs to be studied. We have the hardware for testing this but the procedures and software need to be developed.

The code is written in C# and Python so familiarity with these languages would be advantageous but is not essential as students interested in programming can pick up what they need to know very quickly. If there is time available, the student could also perform some Finite Element Analysis of the tapes to predict the quality of the high speed data transmission. This would involve using the ANSYS system to solve Maxwell’s equations in 2D to determine the E and B fields and hence the impedance of the line and then use a 3D model to determine the attenuation of signals down the line.

Development of a precision magnetometer for the Muon g-2 experiment (8 Weeks)

Dr Sam Henry (sam.henry@physics.ox.ac.uk)
Duration: 8 weeks

The muon g-2 experiment will search for New Physics beyond the standard model of particle physics by making a precise (140ppb) measurement of the anomalous muon magnetic dipole moment. This project concerns the design and construction of a 3He magnetometer, to provide an absolute magnetic field calibration in terms of the Larmor frequency of 3He nuclei. This is measured from the free induction decay of gaseous polarized 3He following a resonant radio frequency pulse excitation. This requires the polarization of a 3He gas sample using the technique of metastability exchange optical pumping (MEOP).

The main focus of the project is designing a 3D model prototyping of the optical pumping probe head including the NMR coil structure and components with CAD software. This project will provide an opportunity for a student to contribute to g-2 experiment and gain experience of optics, NMR techniques, and electronics.

The Front End Test Stand Project: Beam Dynamics & Modelling

Supervisor: Dr Suzie Sheehy, Co-supervisor: Dr Ciprian Plostinar (STFC/RAL) (suzie.sheehy@physics.ox.ac.uk)
Duration: 8 weeks

The Front End Test Stand is a high intensity proton accelerator currently being built at Rutherford Appleton Laboratory. In preparation for beam commissioning, extensive multi-particle simulations are needed to quantify and understand the machine performance in terms of beam loss, activation, emittance growth, etc. This work will concentrate on simulating and planning various measurement scenarios such that the suitability of the current set of diagnostics is fully evaluated. Using existing particle tracking codes, you will be contributing to improving current machine models as well developing new ones and therefore some experience with data analysis and computer programming is an advantage.

Algorithms for Online Optimisation of Particle Accelerator Performance

Supervisor: Professor Riccardo Bartolini (riccardo.bartolini@physics.ox.ac.uk)
Duration: 8 weeks

The overall performance of the electron storage ring is critically dependant on a large number of machine parameters. This performance can be characterised in a number of different ways, such as by measuring electron beam lifetime, transverse stability, injection efficiency, injection transients, instability thresholds and so on. However, it is frequently the case that improving one parameter comes at the cost of harming another. Similarly, given the large number of variables involved in optimising the ring performance, the true, global optimum solution may be difficult to identify using simple parameter scans.

In order to address this problem, flexible optimisation tools are required. These tools should be capable of optimising several parameters at once, using an arbitrary number of variables to achieve this goal (typically the strength of various magnets). It should be possible to apply the tools to any online optimisation problem, and not tied to any particular set of optimisation variables. The tool should also be able to cope with measurement noise on the parameters to be optimised.

The programme involves extensive numerical simulations and the application of the techniques developed to the Diamond Light Source with possible machine shifts at the facility.

Combining real time differential and absolute distance interferometry

Supervisor: Dr Armin Reichold (armin.reichold@physics.ox.ac.uk)
Duration: 8 weeks
Date restrictions: preferably inside 4th July to 23rd September

We wish to combine two distance measurement techniques in the same optical setup. One of the methods will be FSI as described in Opt Express. 2014 Oct 6;22(20):24869-93. doi: 10.1364/OE.22.024869. which can measure distances for short times (shots) at high frequency but not continuously and not with low latency. We therefore wish to combine this method with more conventional methods of differential interferometry that can be used in fast (order of kHz) feedback loops for position control. For this purpose we seek to set up a new interferometer head on an optical table that can combine the two methods and use them simultaneously or sequentially with low dead time. The project will entail the design and setup of the head and the analysis of the data from verification experiments. We hope to achieve a real time measurement of a moving target with low latency and high repetition rate.

Required skills:
Very good command of spoken and written English, must be able to work with laser and as such has to have vision on both eyes (we can provide safety training), knowledge of optics and interferometry principles, practical skills in a laboratory, preferably with optics setups, ability to extend existing computer based analysis algorithms using Java.

Desired skills:
Familiarity with some data analysis package, basic ideas of electronics, interest in optics simulation

Theoretical and experimental studies of multi-cell asymmetric cavity for Energy Recovery Linac

Supervisors: Dr Ivan Konoplev, Prof Andrei Seryi, Dr Andrew Lancaster (ivan.konoplev@physics.ox.ac.uk, andrei.seryi@physics.ox.ac.uk, andrew.lancaster@physics.ox.ac.uk)
Duration: 8 weeks

High-brightness, intense sources of coherent X-ray radiation are extremely useful tools in science and used to probe matter of different kinds and in different states. These radiation sources are usually driven by particle accelerators such as synchrotrons and free electron lasers, vital tools which exist at only a few national laboratories around the globe. The size and energy consumption of such particle accelerators are key reasons for the restricted number of facilities and there are number of projects undergoing to develop more compact and affordable electron beam drivers.
This project is a part of a larger initiative to develop compact, superconducting, RF driven, high current energy recovery linear accelerator (LINAC). Such a LINAC can be used to generate high intensity X-Ray of properties comparable with radiation observed at large synchrotron or FEL facilities. The one of the main challenges of the project is to control and suppress high order modes inside accelerating/decelerating structures, which will be excited by the high current beam. These modes could interfere with the energy recovery and could potentially interrupt the beam transportation through the system. The main tasks will be development of a numerical model using CST microwave studio and experimental mapping of the field inside the cavity using equipment available in the RF laboratory.
The outcome of the project will contribute to the current UH-FLUX research program on development of compact source of coherent radiation. It is expected that the student who will take on this project is familiar with computer codding (MATLAB, C, Python) and EM theory. The researcher will be working in team with senior colleagues and good communication skills are expected. If the project is successful it may lead to a publication and good writing skills will be beneficial.

Novel laser polarisation state generation for particle acceleration

Supervisor: Dr Laura Corner (laura.corner@physics.ox.ac.uk)
Duration: 8 weeks

Recent experiments have shown that it is possible to directly accelerate electrons by tightly focusing radially polarised laser beams. These are usually created with expensive specialist optics that produce imperfectly polarised beams. We have opportunities for a summer student to work on generating these polarisation states directly from fibre lasers by a novel method of combining higher order spatial modes in fibre amplifiers. This project is predominantly experimental and would suit an independent student who is interested in lab work, but the project will also involve the theory and numerical modelling of these polarisation states and their properties.

Multi‐Pulse Laser Wakefield Accelerators modelling

Supervisor: Roman Walczak (roman.walczak@physics.ox.ac.uk)
Duration: 8 weeks

Multi‐Pulse Laser Wakefield Accelerators It has now been shown experimentally that electrons can be accelerated to 4‐GeV energies in a plasma wakefield driven by a single high‐intensity laser pulse. However, such laser systems have limited repetition rates and low wall‐plug efficiency. An alternative method is to resonantly excite plasma oscillations using a train of laser pulses of lower intensity spaced by the plasma period to drive multi‐pulse laser wakefield accelerators (MP‐LWFAs). Fibre and thin‐disc laser technologies offer the possibility to drive MP‐LWFAs efficiently and at high repetition rate (tens of kHz), opening a new domain for applications including compact X‐ray sources with high mean brightness.
The goal of this project is modelling of wakefields driven by experimentally realizable pulse trains taking into account effects such as modifications of laser pulses as they propagate through plasma.

As the energy is transferred from laser pulses to plasma, creating a wake, the energy and the shape of laser pulses change. The modelling will be done by means of computer simulations, using programs such as WAKE and EPOCH.

For background reading, this paper http://stacks.iop.org/0953‐4075/47/234003 is recommended.

Phase feed-forward R&D for future colliders

Supervisor: Professor Philip Burrows (phil.burrows@physics.ox.ac.uk)
Duration: 8 weeks

Beam phase feed-forward systems are needed for future colliders, such as the Compact Linear Collider (CLIC), to ensure synchronisation of the drive beam and main beam and hence efficient transfer of RF power between the two. The CLIC Test Facility (CTF3) at CERN provides a prototype of the CLIC drive-beam generation complex and we have implemented a prototype beam-phase feed-forward system there. Initial results were obtained in late 2015, and the plan is to try to gain improved results on beam stabilisation at the 50-femtosecond level in further runs starting in the summer of 2016. The project will comprise beam tracking studies and beam phase studies utilising data from CTF3 and the CTF3 beam transport model.