Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163Ho ions

Abstract

For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of 163 Ho using MMCs having the radioactive 163 Ho ions implanted in the absorber. The implantation of 163 Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. In addition an optimized detector design for future 163 Ho experiments is presented.

Determination of the neutrino mass by electron capture inHo163and the role of the three-hole states inDy163

“…The three-hole contributions can practically not be seen even in this logarithmic 10 plot. Figure 3 compares in a logarithmic 10 plot the deexcitation spectrum of the one-hole states, the one-plus two-hole and the one-plus two-plus three-hole excitations with the ECHo data [19,20]. The experimental spectrum in binned into 2 eV.…”

“…The three experimental peaks between 1.2 and 1.6 keV originate from a 144 P m contamination. Figure 4 shows in detail a comparison of the one-, the two-and three-hole spectrum with the ECHo data [19,20] around the area of the N2 4p1/2, 0.333 keV and the N1 4s1/2, 411 keV hole states. Table 2: The 39 (from number 7 to 45) two-hole excitation energies E C and the widths Γ in 163 Dy with quantum numbers n, ℓ, j are listed.…”

“…Table 2: The 39 (from number 7 to 45) two-hole excitation energies E C and the widths Γ in 163 Dy with quantum numbers n, ℓ, j are listed. We adopt here the first hole values for E c and the width Γ of the ECHo collaboration [13,16,19,20] and add the excitation energies of the second hole taken by Robertson [6] taken from Weast tabulated in the Handbook of Chemistry [26]. The data measured by the ECHo collaboration [19], [20] are listed in table 1.…”

“…The three-hole states can hardly be seen. log-exp log-3-holes log-2-holes log-1-holes Figure 4: (Color online) Comparison of the logarithmic 10 bolometer spectrum around the N1 = (4s1/2) −1 0.411 keV (relative probability to the 3s1/2 state 24.4 %) and N2 = (4p1/2) −1 0.333 keV (relative probability 1.22 % ) resonances with the ECHo data [13,16,19,20]. At 0.569 keV one sees the degenerate two-hole states N1 = (4s1/2) −1 , N4 = (4d3/2) −1 with the relative probability of 0.088 % and N1 = (4s1/2) −1 , N5 = (4d5/2) −1 with the relative probability of 0.125 % (total 0.213 %).…”

“…At 0.569 keV one sees the degenerate two-hole states N1 = (4s1/2) −1 , N4 = (4d3/2) −1 with the relative probability of 0.088 % and N1 = (4s1/2) −1 , N5 = (4d5/2) −1 with the relative probability of 0.125 % (total 0.213 %). The resonance energies and the widths are taken from the ECHo collaboration [19,20]. The theory does not include the finite resolution of the measurement, which is about 10 eV FWHM.…”