Abstract:
A dosimeter is described that does not show differences in sensitivity over its sensitive area when ambient pressure changes. To that purpose the measuring chamber and a pressure compensation element together form a single gastight chamber having at least partially walls of soft material. Thereby the pressure inside the measuring chamber is essentially equal to ambient pressure whereby no mechanical distortion of the measuring chamber over its sensitive area takes place.
Abstract:
A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel (10) containing an ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode (14), a cathode (12), a grid (16) and a plurality of annular field shaping rings (18), the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30°C.
Abstract:
A probe assembly is disclosed comprising an inlet for receiving an eluent from a chromatography device; an outlet (120) for delivering the eluent to an ion source of a mass spectrometer; and an attachment device (122) for attaching the outlet to the mass spectrometer. The outlet comprises an electrically conductive capillary (124) and an electrically conductive member (129) surrounding at least part of the electrically conductive capillary (124). The electrically conductive member (129) is arranged to receive a voltage upon connection of the attachment device (122) to the mass spectrometer and the electrically conductive member (129) is arranged to provide an electrical connection from the electrically conductive member (129) to the electrically conductive capillary (124).
Abstract:
A direct ion storage (DIS) radiation detector or dosimeter has a design that is easy and low cost to manufacture using semiconductor processing techniques. The detectors include internal communications interfaces so they are easy to read. Different interfaces, including wired, e.g. USB ports, and wireless interfaces, may be used, so that the dosimeters may be read over the internet. The detectors can thus be deployed or used in a variety of detection systems and screening methods, including periodic or single time screening of people, objects, or containers at a location by means of affixed dosimeters; screening of objects, containers or people at a series of locations by means of affixed dosimeters, and surveillance of an area by monitoring moving dosimeters affixed to people or vehicles.
Abstract:
Components of scientific analytical equipment. More particularly, ion detectors of the type which incorporate electron multipliers and modifications thereto for extending the operational lifetime or otherwise improving performance. The ion detector may be embodied in the form of a particle detector having one or more electron emissive surfaces and/or an electron collector surface therein, the particle detector being configured such that in operation the environment about the electron emissive surface(s) and/or the electron collector surface is/are different to the environment immediately external to the detector.
Abstract:
A direct ion storage (DIS) radiation detector or dosimeter has a design that is easy and low cost to manufacture using semiconductor processing techniques. The detectors include internal communications interfaces so they are easy to read. Different interfaces, including wired, e.g. USB ports, and wireless interfaces, may be used, so that the dosimeters may be read over the internet. The detectors can thus be deployed or used in a variety of detection systems and screening methods, including periodic or single time screening of people, objects, or containers at a location by means of affixed dosimeters; screening of objects, containers or people at a series of locations by means of affixed dosimeters, and surveillance of an area by monitoring moving dosimeters affixed to people or vehicles.
Abstract:
A direct ion storage (DIS) radiation detector or dosimeter has a design that is easy and low cost to manufacture using semiconductor processing techniques. The detectors include internal communications interfaces so they are easy to read. Different interfaces, including wired, e.g. USB ports, and wireless interfaces, may be used, so that the dosimeters may be read over the internet. The detectors can thus be deployed or used in a variety of detection systems and screening methods, including periodic or single time screening of people, objects, or containers at a location by means of affixed dosimeters; screening of objects, containers or people at a series of locations by means of affixed dosimeters, and surveillance of an area by monitoring moving dosimeters affixed to people or vehicles.
Abstract:
An ionization chamber is provided for the detection of nuclear radiation. The chamber is a vessel which acts as a cathode wherein at least one anode is disposed within the chamber and off-set from a center axis of the chamber. The chamber can be made from variety of shapes but is cylindrical in the preferred embodiment. The device contains two anodes in the preferred embodiment which are both off-set from the center axis. One anode collects the free floating electrons which are produced in response to particle ionization and therefore has a collected charge applied thereto. The second anode has the charge induced by immobile ions. The induced charge is subtracted from the collected charge thereby providing an improved resolution for the ionization chamber which translates into a more accurate result. In the preferred embodiment, a pressurized noble gas, such as xenon, is used. In some special geometries of the chamber, one of the anodes becomes part of the cathode and the charge induced by immobile ions becomes negligibly low. Thus the subtraction of the induced charge is not required.
Abstract:
A detection medium for a kinestatic charge detector is a mixture of gases, typically including at least one noble gas such as zenon or krypton. The medium can be pressurized to improve resolution and temperature can also be applied to the medium for improving resolution. Various additive or dopant gases can also be introduced to improve resolution.
Abstract:
To enable an ionization chamber used for measuring the intensity of a beam of ionizing radiation, for example an electron beam produced by a linear accelerator and used for radiotherapy, both to give an output signal which is independent of ambient pressure and temperature and to present a low weight of scattering material per unit area to the beam, the chamber is of flexible construction so that the volume of gas in it adapts to ambient pressure and temperature, and such that the weight of gas in the active region between the electrodes per unit area remains substantially constant. Suitably, the electrodes are conductive layers on flexible plastics sheets, an outer annular portion of one sheet providing a flexible connection between two opposed chamber wall portions which remain substantially planar and parallel; the proportional change (.DELTA.V.sub.1 /V.sub.1) in a volume bounded by the opposed wall portions and including the active region equals the proportional change (.DELTA.V.sub.2 /V.sub.2) in the remainder (V.sub.2) of the internal volume.