Status and plans for 2014, CERN NA63

We summarize the status and plans for the future for the CERN NA63 collaboration.\n\nA systematic study of the structured target 'resonance' appearing from radiation emission by electrons passing two amorphous foils positioned with separations in the range $10-20000~\mu$m was performed in September 2012. The results - recently submitted for publication - confirm a previously obtained result \cite{Ande12a} that by this method, the formation length - of macroscopic dimensions up to 0.5 mm - for the generation of MeV-GeV radiation from multi-hundred GeV electrons can be \emph{directly} measured. In fact the results obtained allow a distinction between competing theories \cite{Blan97a,Baie99b}, showing that it is unlikely that the correction-term introduced by Blankenbecler holds true \cite{Blan97b}.\n\nFurthermore, with a substantially improved setup compared to the run in 2010 (where the deconvolution of synchrotron radiation prevented results in the most interesting regime below 0.5 GeV), we investigated again the impact of the Landau-Pomeranchuk-Migdal (LPM) effect with 178 GeV electrons, in particular for low-$Z$ targets where a discrepancy between experiment and theory might turn up. Measurements with 20 GeV electrons in a Cu target shows no indication of the 'kink-like' structure seen in Migdal's theory (the most widely used) for photon energies around 300 MeV. The absence of this structure is in agreement with simulations, and is due to the 'smearing' of the effect from multi-photon emission. These results have been accepted for publication.\n\nA short test measurement of the efficiency of production for positrons originating from electrons impinging on an axially aligned diamond crystal was also performed, where the aim in the run proposed for 2014 is to measure the production angles and energies by means of so-called MIMOSA detectors arranged in a magnetic spectrometer configuration with a permanent-magnet-based magnetic dipole. For the 2012 run, however, the track-reconstruction algorithm yields too few events, most likely due to a too low efficiency of each detector. This was not realised at the time of the test, that nevertheless was useful in establishing the functionality of the rest of the setup as well as the alignment of the diamond $\langle100\rangle$ crystal.\\\n\nFor the future, we propose to measure the production angles and energies of positrons produced by 10-50 GeV electrons penetrating a diamond crystal along the $\langle100\rangle$ axis. Furthermore, we ask for beam time with ultra relativistic heavy ions, as soon as CERN is able to deliver unbunched beams of these, to investigate nuclear size effects in a number of emission processes.