Medipix USB

Medipix2 is a single-photon counting pixel readout chip, developed by the CERN Medipix collaboration:

http://medipix.web.cern.ch/MEDIPIX/Medipix2/indexMPIX2.html

Currently, we are using the Medipix USB interface developed by IEAP at Czech Technical University, Prague, to read out these detectors.

Using the interface

Information on using the interface can be found on IEAP's website.

USB interface main page: http://aladdin.utef.cvut.cz/ofat/others/USB_Interface/index.html . As well as information on the interface, this has the USB driver needed to operate the device.

Pixelman control software: http://aladdin.utef.cvut.cz/ofat/others/Pixelman/Pixelman.html . Includes a guide to using the software, and a download of the software. To use recent versios of the software, new Windows libraries must be installed (available from the download page).

Additional notes

Power supply: In principle, the USB interface should be able to run from the 500mA that the USB port supplies. However, when running like this errors sometimes occur, because the interface attempts to draw too much current and the voltage drops. (According to the FAQ, this can depend on the USB controller within the PC.) The most convenient solution is to put a powered USB hub between the PC and the interface. This also is a useful way of extending the length of cable between the PC and lab setup.

If you have any other comments, please add them!

My thesis is available from the PPE page http://www.gla.ac.uk/departments/particlephysicsexperiment/currenttheses/

Other documentation

EnergyCalibrationOfMedipix.pdf - A report by Celine Lebel (Universite de Montreal) which includes a step-by-step guide to using the interface.

medipix2_interface_vykydal_NIM.pdf - Zdenek Vykydal et al. (CTU, Prague), NIMA vol 563 (1), 112-155, 2006. Paper on the USB interface.

Medipix2_a_64-k_Pixel_Readout_Chip_With_55.pdf - Xavier Llopart et al. (CERN), IEEE TNS vol 49 (5), 2279-2283, 2002. Paper on the Medipix2 chip.

Other useful papers

Imaging_properties_of_the_Medipix2_system_exploiting_single_and_dual_energy_thresholds.pdf - L. Tlustos et al., IEEE TNS, 2006. This paper reviews aspects of Medipix imaging like threshold equalisation and flat-field correction, then goes on to deal with the modulation transfer function and the modulation transfer function. Useful general reference.

cunningham_1999.pdf - "Signal-to-noise optimization of medical imaging systems", published J.Opt.Soc.Am.A, vol 16 (3) 621-623. Covers theory on image quality, including distinctions between MTF, signal-to-noise ratio, and detective quantum efficiency (an overall measure of SNR at different frequencies).

Moy_2000.pdf - "Signal-to-noise ratio and spatial resolution in x-ray electronic imagers: is the MTF a relevant parameter?", published Med Phys., vol 27 (1) 86-93. Another useful discussion of image quality, including the effects on image quality of different blurring mechanisms.

Medipix MATLAB Scripts

A collection of MATLAB scripts that can be used for data analysis - e.g. finding spectra from THL scans, and calculating the MTF from edge images.

-- DavidPennicard - 30 Jul 2008