Read-out methods

If the signal could be measured without noise, it would be possible with any method to define the position of an avalanche. But, gas amplification is a statistical process, and the signals underly fluctuations in amplitude, which have to be taken into account in the read-out methods. 

In the following section we will discuss several read-out methods of position sensitive detectors. They rely either on the accurate measurements of charges or of time differences between signals. 

The spatial solution is the same as with the resistive charge division method and is given by expression The resolution is solely a function of the capacitance of the read-out elements, and so there is no fundamental improvement to be expeced as compared to the resistive charge division. However, the elegant read-out method has the advantage that the read-out plane can be produced with high mechanical accmacy, and that a minimum nimiber of components are necessary. 

At SRS at Daresbury also the delay-line read-out method has been chosen The detector system with an area of 200 mm x 200 mm has a resolution of about (2x2) mm. The count rate capability is given as 1,5 10 sec... 

A more advanced read-out method, which also depends on segmentation, is the so called centroid finding method Spatial resolutions of the order of 0,1 % have been reported. The method is however quite involved concerning the processing electronics and has been applied only to a neutron detector at present The centroid finding technique is certainly very promising for the application in synchrotron radiation experiments. 

Organometallic Components Ibr Organometallic Bioprobes Opening up the Advantages of IR-based Read-out Methods... 

Nordstrom M, Keller S, lillemose M, Johansson A, Dohn S, Haefliger D, Blagoi G, Havsteen-Jakobsen M, Boisen A (2008) SU-8 cantilevers for bio/chemical sensing fabrication, characterisation and development of novel read-out methods. Sensors 8 1595-1612... 

Biosensors Using Lasers, Figure 7 Scheme of the opticai read-out method for a microcantiiever bending evaiuation. The dispiacement of the free end of the cantiiever is measured by monitoring the opticai deflection of an incident iaser beam on a position-sensitive detector... 

Droplet based Lab-on-Chip devices represent a class of microfluidic systems that have been developed to miniaturize chemical, biochemical or cellular analysis. These devices utilize various droplet dispensing and manipulation mechanisms to isolate and control liquid-phase droplets of sanities and/or reagents surrounded by a gas or an immiscible liquid. The droplets may be completely surrounded by the medium or may be placed onto a solid surface whose material properties are chosen to provide droplet confinement, chemical functionalization, or control of droplet motion. The devices also have some type of assay read-out method with associated hardware, software and data display. 

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