Photon determination

Consider you want to trace the deposition of particulate matter using the stable activable tracer In. The dilution factor between the point of release and the point of sampling is 106. Assume the samples that are collected are activated in a thermal neutron flux of 3 x 1012 n/cm2-s for 10 min. Further assume a 1% efficiency for detecting the emitted photons. Determine the minimum amount of In that must be released to ensure the uncertainty in the measured sample concentrations is 5%. 

Choice B is true for hydrogen. Atoms with more than one electron are more complex. The frequency of individual photons, not the number of photons determines whether the photoelectric effect occurs, so choice C is true. 

The frequency of a certain beam of light is 7.00 X lO Vs. Calculate the wavelength and the energy of its photons. Determine in what portion of the electromagnetic spectrum the beam lies. 

Electromagnetic radiation consists of a stream of photons. Each photon is made up of an electric field component and a magnetic field component, and these two components are mutually perpendicular. The frequency of a photon determines how fast the electric field component and magnetic field component will pulse, or beat. Radio-frequency electromagnetic radiation at 500 MHz will thus have a magnetic field component that beats 500 million times a second, by definition. 

Hence, the number of photons determining the pulse height is normally distributed ... 

Polarization For plane-polarized (also called linearly polarized) photons, the plane within which the electric field vector oscillates can sit at any angle to a reference plane containing the wave vector, as shown in Figures 2A and 2B. Other polarization states are also possible in the right- and left-handed circular polarizations depicted in Figures 2C and 2D, the electric field vector sweeps out a helix about the direction of propagation. Elliptical polarization states are of an intermediate nature, between linear and circular. Together, the wave vector and polarization of a photon determine its mode. 

Matscheko and Ribberfors, A Compton scattering spectrometer for determining X-ray photon energy spectra. Phys. Med. Biol., 1987. 32(5) p. 577-594. 

It was found that that in the case of soft beta and X-ray radiation the IPs behave as an ideal gas counter with the 100% absorption efficiency if they are exposed in the middle of exposure range ( 10 to 10 photons/ pixel area) and that the relative uncertainty in measured intensity is determined primarily by the quantum fluctuations of the incident radiation (1). The thermal neutron absorption efficiency of the present available Gd doped IP-Neutron Detectors (IP-NDs) was found to be 53% and 69%, depending on the thicknes of the doped phosphor layer ( 85pm and 135 pm respectively). No substantial deviation in the IP response with the spatial variation over the surface of the IP was found, when irradiated by the homogeneous field of X-rays or neutrons and deviations were dominated by the incident radiation statistics (1). 

Kummel A C, Sitz G C and Zare R N 1986 Determination of population and alignment of the ground state using two-photon nonresonant excitation J. Chem. Phys. 85 6874-97... 

Phase interference in optical or material systems can be utilized to achieve a type of quantum measmement, known as nondemolition measurements ([41], Chapter 19). The general objective is to make a measurement that does not change some property of the system at the expense of some other property(s) that is (are) changed. In optics, it is the phase that may act as a probe for determining the intensity (or photon number). The phase can change in the comse of the measurement, while the photon number does not [126]. 

When the states P1 and P2 are described as linear combinations of CSFs as introduced earlier ( Fi = Zk CiKK), these matrix elements can be expressed in terms of CSF-based matrix elements < K I eri IOl >. The fact that the electric dipole operator is a one-electron operator, in combination with the SC rules, guarantees that only states for which the dominant determinants differ by at most a single spin-orbital (i.e., those which are "singly excited") can be connected via electric dipole transitions through first order (i.e., in a one-photon transition to which the < Fi Ii eri F2 > matrix elements pertain). It is for this reason that light with energy adequate to ionize or excite deep core electrons in atoms or molecules usually causes such ionization or excitation rather than double ionization or excitation of valence-level electrons the latter are two-electron events. 

Analytical Applications. Chemiluminescence and bioluminescence are useful in analysis for several reasons. (/) Modem low noise phototubes when properly instmmented can detect light fluxes as weak as 100 photons/s (1.7 x 10 eins/s). Thus luminescent reactions in which intensity depends on the concentration of a reactant of analytical interest can be used to determine attomole—2eptomole amounts (10 to 10 mol). This is especially useful for biochemical, trace metal, and pollution control analyses (93,260—266) (see Trace and residue analysis). (2) Light measurement is easily automated for routine measurements as, for example, in clinical analysis. 

Ideal Performance and Cooling Requirements. Eree carriers can be excited by the thermal motion of the crystal lattice (phonons) as well as by photon absorption. These thermally excited carriers determine the magnitude of the dark current,/ and constitute a source of noise that defines the limit of the minimum radiation flux that can be detected. The dark carrier concentration is temperature dependent and decreases exponentially with reciprocal temperature at a rate that is determined by the magnitude of or E for intrinsic or extrinsic material, respectively. Therefore, usually it is necessary to operate infrared photon detectors at reduced temperatures to achieve high sensitivity. The smaller the value of E or E, the lower the temperature must be. 

The responsivity and g-r noise may be analyzed to obtain background photon flux and temperature dependence of responsivity, noise, and detectivity. Typically, n > p, and both ate determined by shallow impurity levels. The minority carrier density is the sum of thermal and optical contributions. 

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