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ERLP Construction, Commissioning and Further Development

The Energy Recovery Linac Prototype, ERLP, is a 35MeV energy recovery test facility that is currently approaching completion at Daresbury Laboratory.  It is shown schematically in the diagram below which shows the relative positioning of the laser driven photoinjector, the two super-conducting linear accelerator modules and the mid infra-red free electron laser (FEL).

Schematic of the ERL Prototype Schematic of the ERL Prototype in place in the tower experimental areas - click image to see larger size

Construction & Commissioning

Installation work on ERLP has progressed well as can be seen from the overview photographs taken last month.Views of the ERLPViews of the ERLP
Views of the ERLP taken during March 2007

Construction of the photoinjector is complete.  First electrons were obtained in August of 2006 and current work is now focussing on extending the lifetime of the photocathode, optimising the photoinjector output comparison of the measured properties with those predicted by simulation software.

Image of First beam
First electrons from the ERLP photoinjector August 16th 2006

Assembly of the ERLP beam transport system is well advanced with around eighty percent of the system already under vacuum. 

First cool-down of the linac and booster to 2 K, which took place during October of 2006, revealed a number of design issues that have to be rectified before the units can undergo RF ‘power-up’. The design amendments are in the process of being implemented and further commissioning is planned for May/June of this year.

ERLP Light Sources

Further information on the light sources of ERLP »

Further Development

In parallel with build and commissioning work on ERLP itself there are also vigorous programmes of work ultimately aimed at realising the potential of ERLP as a high quality electron injector for a compact Fixed Field Alternating Gradient test machine and for exploiting the light source capabilities of ERLP for medical and dynamics studies.  This work is complemented by dynamics studies involving a femtosecond pulse laser and the SRS.


Laser activity on 4GLS and ERLP related programmes is rapidly growing.  The activities encompass:

Much of this work is being undertaken in collaboration with major laser groups in the UK.

Sub ps X-ray pulse generation

This activity is being led by Dr Gerd Priebe.  The multi-TW laser has been installed and work is now underway on the design and build of the TW laser to ERLP transport line.3D Schematic3D Schematic of the TW laser to ERLP photon transport line


THz radiation will be extracted from the last bending magnet in the bunch compressor where the electron bunch is at its shortest. The radiation will then to be transported through a labyrinth into the diagnostic room for measurement and then on to the Tissue Culture Laboratory for experiments aimed at the understanding how THz radiation affects live cells.  This work is under the guidance of Prof Peter Weightman.

Laser-SR pump-probe experimentation
This work, which is being led by Prof Wendy Flavell, has started on the SRS – it will utilise ERLP in the future.

A high power table-top fs laser system has been developed in collaboration with the Photon Science Institute (PSI) of the University of Manchester, and we are presently working to synchronise this with pulses from the SRS.  Dr Darren Graham is in charge of this work.  A user group has been established, and several grant applications have followed.  The science programme includes a wide-range of pump-probe experiments.  For example, a collaboration between Imperial College and the University of Manchester aimed at designing new hybrid solar cells for rooftop microgeneration has recently been funded by EPSRC.  In these experiments, ERLP and the SRS will be used with the fs laser system to measure ultrafast carrier transport in ZnO nanorods.  

In all cases, the planned studies provide the groundwork for a part of the future science programme envisaged for 4GLS.

newly installed laser
The newly installed laser for laser-SR pump-probe experiments on the SRS.

The specification of the pump-probe fs laser system »

Electro-optical diagnostics

This work is being led by Dr Steve Jamison.  Further details will be posted shortly.