Archive - FP6

PJCK reported on the status of the µSR instrumentation at ISIS, with a particular regard to the new developments concerning the new high magnetic field spectrometer.

TS reported about the latest developments concerning the simulation and testing of position-sensitive detectors in muon spectroscopy.

An overview of the research carried out by JRA8 in the framework of the FP6 program during the last years.

PJCK gave a brief introduction to the future developments foreseen in FP7, concerning the muon spectroscopy technique.

PJCK reported on the current status of the µSR instrumentation in Europe and outlined the roadmap to future developments and improvements.

RS reported on the status of research toward high-speed, field-insensitive detectors, of which the avalanche photo-diodes represent the most promising application.

RS highlighted the importance of analogue detection technique in future high-rate experiments and its possible application in RF experiments.

TL summarized the results of simulations of µ+SR experiment in high magnetic fields and their relevance for predicting the muon ensemble's spin and direction in different conditions.

TS reported about the possibility of using silicon detectors and scintillating fibers as position-sensitive detectors in muon spectroscopy for achieving better spatial resolution or higher detector segmentation.

RS presented the status of the HMF project at PSI. A commercial predesign study for a cold split pair magnet from Cryogenic LTD allowed realistic simulations performed by TL within WP2. Several different detector types have been (or will be) tested with respect to their performance in high magnetic fields (Avalanche Microchannel Photodiodes, Multichannel PMTs, Hybrid Avalanche Photodetectors).

SC reported on the design criteria and challenges in building a High Field spectrometer at the ISIS facility. This new instrument will be designed to offer an order of magnitude improvement in both magnetic field and count rate, configured specifically for longitudinal field experiments. Building such an instrument presents a number of challenges, particularly in the design of a highly segmented detector array that is capable of working over a wide field range.

TL summarized the problematic that µSR experiments encounter in large applied magnetic fields.

TP presented the main features of Geant4 toolkit and the simulation of the Low Energy µSR experiment. The chosen simulated geometry was from the trigger detector to the multiple channel detector. The muon physics (polarized decay, spin rotation in magnetic field, etc.) is now implemented in the new 7.0 release of Geant4 and tests indicate a good agreement with theoretical predictions. The Femlab finite elements solver was used to generate the inhomogeneous electric fields of the third lens and the conical anode. Using these field maps in Geant4, it has been possible to show particle trajectories, focal lengths and beam deviation were in good agreement with theoretical predictions and experimental values. Finally, the sensitive detection class in Geant4 has been shown to be suitable for low energy muon applications (e.g. the MCP counter and scintillators).

EM pointed out the advantages of position sensitive detectors for µSR spectrometers. The position information will allow to increase the usable muon intensity at PSI by one (time-integral method) or even two orders of magnitude (time-differential method) and also to reduce the backround in the spectra significantly. A new type of experiments studying transient effects would be possible if measurements could be performed on a minutes timescale. In addition, the use of very small samples (few 100 microns for bulk, some mm for LEM) will then be possible.

TS reported about the use of silicon detectors as position-sensitive detectors in muon spectroscopy. The peculiarities of the specific application, like the limited energy of positrons and the need for fast timing, seem to rule out many of the existing detectors. The constraints posed by muon spectroscopy indicate thin silicon pixel detectors in tandem with fast scintillating fibers as the most promising solution.

Comparing the efficiency of scintillating fibres: beta decay electrons vs. muon decay positrons. Location: Università di Parma, Parma (Italy) Contact: T. Shiroka 2 September 206

The effect of applied magnetic fields on positron trajectories in the µ+SR experiment: comparison of simulation and experiment. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: T. Lancaster 4 September 2006

Study of the timing properties of a Hamamatsu R9503U-04-M064M HPD - Applicability as a fast detector for µSR. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: R. Scheuermann 8 February 2006

Study of Avalanche Microchannel / Micropixel Photodiodes (AMPDs) as Photodetectors for µSR Spectrometers. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: A. Stoykov 19 December 2005

Light Collection Efficiency from Thin Plastic Scintillators. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: A. Stoykov

Muon beams in applied magnetic fields: comparison of simulation and experiment. Location: Oxford University, Oxford (UK) Contact: T. Lancaster 5 December 2005

Performance of a R7110U-07 HAPD in up to 4.8 Tesla Magnetic Field. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: R. Scheuermann 21 December 2004

A numerical simulation of the µ+SR experiment. Location: Oxford University, Oxford (UK) Contact: T. Lancaster 13 December 2004

Silicon Avalanche Photodiodes (APD) as high field detectors for µSR spectroscopy. Location: Laboratory for Muon Spin Spectroscopy, PSI, Villigen (Switzerland) Contact: R. Scheuermann 11 August 2004