Jose Gomez

Low Temperature Detector Development:

I’m working in the development of a cryogenic charge particle detector. These consist of three components: an absorber, a thermometer and a thermal coupling to a heat sink. Incident particles are stopped in the absorber. After thermalization of the kinetic energy the temperature rise of the absorber is read by the thermometer. Finally the deposited heat flows to the heat sink through the thermal coupling. The sensitivity of such detectors is inversely proportional to their heat capacity. Therefore these detectors are operated at low temperatures (down to 300 mK): according to the Debye law the heat capacity for insulators is decreasing with the third power of the temperature. These detectors have very good resolution for detection of energetic heavy ions. The objective is to develop our detector for alpha-source tests, followed by possible beam line tests at the Maier-Leibnitz tandem accelerator laboratory.

Beschleunigermassenspektrometrie (AMS):

I’m also involved in the AMS measurements of rare isotopes of interest in astrophysics in the AMS facility at the Maier-Leibnitz Laboratory (MLL) in Garching, the most sensitive facility to measure long-lived radionuclides in the mass range around A=60 (e.g. ⁵³Mn, ⁵⁹Ni, ⁶⁰Fe, ⁶³Ni). This system is equipped to detect extremely low ratios in the order of 10^-16, depending on the isotope.

Accelerator Mass Spectrometry (AMS) is a highly sensitive technique that combines mass spectrometry with particle accelerators. The use of high energies makes possible the detection of radioactive isotopes with long half-lives. Mass spectrometry (MS) uses the fact that a charged particle follows a trajectory that depends on its mass and its charge. The use of kinematics filters based on magnetic and electrostatic fields makes possible the selection of the desired particles. However, its sensitivity is limited due to the existence of interferences such as molecules or isobars.

I made my PhD in a low energy AMS facility located in Spain (CNA, Centro Nacional de Aceleradores) which utilizes a system based on a 1 MV Tandem Accelerator. This facility was installed in 2005 and since then we made the experimental set up of a wide range of radionuclides: ¹⁰Be, ¹⁴C, ²⁶Al, ¹²⁹I and Pu isotopes. My work was focused in the experimental set up of the system for ¹²⁹I measurements.