Development of Calorimetric Low-Temperature Detectors for Application in Heavy Ion Physics

• Applicant: Dr. Saskia Kraft-Bermuth
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 117659296

Microcalorimeters detect the temperature change of an absorber after an incoming particle has deposited its kinetic energy as heat. This operation principle provides considerable advantage over conventional detectors with respect to energy resolution, detection efficiency, energy threshold and radiation hardness. The detection of X-rays with microcalorimeters achieves a relative energy resolution of 1–3 ‰ in the energy regime of 1–100 keV. For the direct, energy-sensitive detection of heavy ions, a relative resolution of 1–7 ‰ has been obtained, which means an improvement of one order of magnitude as compared to conventional heavy-ion detectors.The proposed Emmy-Noether research group will develop and adapt microcalorimeters especially for the needs of heavy-ion physics experiments. One focus lies on microcalorimeters for the direct energy-sensitive detection of heavy ions: The main aim is to investigate and improve the performance of such detectors in the energy range below 0.1 MeV/u, which has not been addressed up to now. The application of such detectors for the precise determination of energy losses of heavy ions in solids will provide important information on the energy deposition mechanisms like ionization, charge exchange or the direct elastic scattering of nuclei.Microcalorimeters for the detection of X-rays will be applied at the newly constructed ion-trap facility HITRAP (Gesellschaft für Schwerionenforschung, Darmstadt) to probe Quantum Electrodynamics by precise measurements of the electron transition energies in highly-charged heavy ions (Lamb shift). Especially for unstable nuclei, this method will also open access to an alternative way to determine nuclear charge radii.

• DFG Programme: Emmy Noether Independent Junior Research Groups
• Major Instrumentation: Cryostat (second year)
• Instrumentation Group: 8550 Spezielle Kryostaten (für tiefste Temperaturen)