Project Details
Projekt
Measurement of QEC by Penning-Trap Mass Spectrometry
Applicant
Professor Dr. Klaus Blaum
Subject Area
Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
Term
from 2015 to 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 254114301
Within the framework of the second phase of the ECHo project (ECHo-100k) the team of the PI has the goal to provide the ECHo experiment with an independently and directly measured Q-value of the electron capture (EC) in 163Ho with an uncertainty of a few eV. The tool to be used to reach this goal is the high-precision Penning-trap mass spectrometer PENTATRAP, which is located at the MPIK and is presently in the commissioning phase. An accomplishment of the ultimate goal depends on the successful realization of two main subprojects: The first subproject encompasses a development of a stable and reliable source of highly charged 163Ho ions. Since the sample contains just a few nanograms of 163Ho and a production rate of a few ten ions per second is needed, the source will be optimised with stable 165Ho. For this, a dedicated test setup is being under development. It is composed of an electron beam ion trap (EBIT), a 90° magnetic separator and a diagnostic station. In the EBIT various ion production techniques will be extensively investigated in order to find the one which would suit our demands best. A 90° magnetic separator with a mass-to-charge resolving power of about 400 will be placed after the EBIT to select a certain charge state of the ions which will then be sent to a diagnostic station consisting of a microchannel plate (MCP) with a phosphor screen. The results obtained with the test setup will allow us to build an ion source which will provide the Penning-trap mass spectrometer PENTATRAP with a sufficiently large number of highly charged ions of 163Ho. The second subproject consists of the commissioning of the Penning-trap mass spectrometer PENTATRAP. The mass spectrometer has been designed to measure mass ratios of highly charged ions with a relative uncertainty of 10E-11. It employs five Penning traps situated inside the cold bore of a 7T magnet and a dedicated detection system for image charge detection. The commissioning implies, first, a successful transport of various ions from an ion source to the mass spectrometer with successive trapping of the ions in a chosen charge state in any of the five traps for at least several hours. Second, the trapped ions must be prepared for measurements by cooling their trap motions by means of resistive ion cooling. Third, the traps must be optimized with reference ions, e.g., highly charged ions of argon. Fourth, the ability to determine the cyclotron frequency of the reference ions with a needed relative uncertainty of at most 10E-11 must be demonstrated with different phase resolving detection techniques. Finally, the mass ratio of two species with well-known masses, e.g. 187Re and 187Os, must be determined correctly with a relative uncertainty of about 10E-11. A successful realization of these subprojects will enable us to address our ultimate goal – the determination of the Q-value of the EC in 163Ho with an uncertainty of a few eV.
DFG Programme
Research Units
Co-Investigator
Dr. Sergey Eliseev
