(a) A CDMS “iZIP” detector with photolithographically defined phonon sensors. The crystal is 3 in. in diameter and mounted in its copper housing. The top surface contains an outer, guard phonon sensor, and three inner phonon sensors from which an event's position estimate can be made. The opposite face (not shown) has a similar channel design, but rotated 60°. (b) Close-up view of the iZIP phonon channel and ionization channel (thin lines in between the phonon sensors). The phonon channel is held at ground and the ionization channel is held at ∼±2 V for the top (bottom) surfaces.
Description of ion-electron potential interaction process which shows that for ion velocity much less than the Fermi velocity (v ≪ v f ) the number of electron states that an ion can interact with scales like v.
Phase velocities in silicon. The distance from the origin represents the phase velocity speed (in m/s). The first three plots are views from the north pole. The fourth view containing all three surfaces is offset from the north pole. In the plots all modes are equally populated, which does not reflect the actual mode populations.
Group velocities in silicon. Energy is focused in the direction of heavy banding and leads to the term phonon focusing. The distance from the origin represents the speed that phonon energy is carried through the crystal (in m/s). In the plots all modes are equally populated, which does not reflect the actual mode populations.
Phonons isotope scatter off mass defects in the crystal. Equation (7) gives the individual phonon scatter rates. is the group velocity and is the polarization vector.
Longitudinal phonons decay due to nonlinear terms in the elastic coupling constants. is the group velocity and is the polarization vector.
Resultant energies in longitudinal phonon decay in germanium. The two branches L → L + T and L → T + T are shown; the plotted distribution is indicated in bold face in the legend.
Resultant angles in longitudinal phonon decay in germanium. The two branches L → L + T and L → T + T are shown; the plotted distribution is indicated in bold face in the legend.
Energy band structure of germanium, showing the L-valleys at ⟨111⟩, the Γ valley at ⟨000⟩, and the X-valley at ⟨100⟩. Symmetry results in 8 total L-valleys and 6 total X-valleys.
Charge carrier with initial wavevector and final wavevector scattering off of lattice at angle ϕ with respect to and emitting a phonon with wavevector at angle θ with respect to , where the vector momenta sum as shown on right.
Mesh node points r 1, r 2, and r 3 along with the probe point r. The areas a 1, a 2, and a 3 are identically equal to the barycentric coordinates λ1, λ2, and λ3.
TES simulation flowchart.
TES resistor interconnects as modeled using a finite element approximation.
Surface and contour plots of R = R(T, I), , and for a high-Tc, inner iZIP channel. The colors in the surface plot indicate the value of resistance, alpha, and beta with blue representing 0 and red the highest value in the figure. The contour plots show the same information but over a limited current and temperature region. The black dot indicates a nominal bias region, which will affect noise and pulse shape after a radiation interaction in the detector. The gradient in resistance and temperature is generally along the temperature direction, whereas for β it is in a mixed −T + I direction.
TES simulation biasing circuitry. Modeling reflects the biasing circuitry.
Numerical constants for phonon simulations.
Physical constants for Si and Ge crystals. The isotropic hole effective mass m h , and the anisotropic electron effective masses m ∥ and m ⊥ are ∥ and ⊥, respectively, to the conduction valley axes, and conductivity effective mass 3/m c = 1/m ∥ + 2/m ⊥. The incident energy per final electron-hole pair is ε eh , v L the speed of sound, and l 0 = πℏ4ρ/(2m 3Ξ2) is the characteristic range for carrier scattering where Ξ1 (from Ref. 43) or Ξ fit (fit to data50) is the deformation potential.
Physical constants for tungsten TES and aluminum fin simulation, from Ref. 57.
Article metrics loading...
Full text loading...