Ultra-stable implanted 83Rb/83mKr electron sources for the energy scale monitoring in the KATRIN experiment

The KATRIN experiment aims at the direct model-independent determination of the average electron neutrino mass via the measurement of the endpoint region of the tritium beta decay spectrum. The electron spectrometer of the MAC-E filter type is used, requiring very high stability of the electric filtering potential. This work proves the feasibility of implanted 83Rb/83mKr calibration electron sources which will be utilised in the additional monitor spectrometer sharing the high voltage with the main spectrometer of KATRIN. The source employs conversion electrons of 83mKr which is continuously generated by 83Rb. The K-32 conversion line (kinetic energy of 17.8 keV, natural line width of 2.7 eV) is shown to fulfill the KATRIN requirement of the relative energy stability of +/-1.6 ppm/month. The sources will serve as a standard tool for continuous monitoring of KATRIN's energy scale stability with sub-ppm precision. They may also be used in other applications where the precise conversion lines can be separated from the low energy spectrum caused by the electron inelastic scattering in the substrate.Comment: 30 pages, 10 figures, 1 table, minor revision of the preprint, accepted by JINST on 5.2.201

Active Detectors for Plasma Soft X-Ray Detection at PALS

This paper summarizes the work carried out for an experimental study of low-energy nuclear excitation by laser-produced plasma at the PALS Prague laser facility. We describe the adaptation and shielding of single-quantum active radiation detectors developed at IEAP CTU Prague to facilitate their operation inside the laser interaction chamber in the vicinity of the plasma target. The goal of this effort is direct real-time single-quantum detection of plasma soft X-ray radiation with energy above a few keV and subsequent identification of the decay of the excited nuclear states via low-energy gamma rays in a highly radiative environment with strong electromagnetic interference

The physics programme of the MoEDAL experiment at the LHC

The MoEDAL experiment at Point 8 of the LHC ring is the seventh and newest LHC experiment. It is dedicated to the search for highly-ionizing particle avatars of physics beyond the Standard Model, extending significantly the discovery horizon of the LHC. A MoEDAL discovery would have revolutionary implications for our fundamental understanding of the Microcosm. MoEDAL is an unconventional and largely passive LHC detector comprised of the largest array of Nuclear Track Detector stacks ever deployed at an accelerator, surrounding the intersection region at Point 8 on the LHC ring. Another novel feature is the use of paramagnetic trapping volumes to capture both electrically and magnetically charged highly-ionizing particles predicted in new physics scenarios. It includes an array of TimePix pixel devices for monitoring highly-ionizing particle backgrounds. The main passive elements of the MoEDAL detector do not require a trigger system, electronic readout, or online computerized data acquisition. The aim of this paper is to give an overview of the MoEDAL physics reach, which is largely complementary to the programs of the large multipurpose LHC detectors ATLAS and CMS

Semiconductor pixel detectors

Semiconductor pixel detectors were originally developed for particle physics experiments as a logical development from silicon microstrip detectors. offering the potential for high spatial precision, two dimensional location of ionising charged particle trajectories. The development became practical, as with microstrip detectors. only with the availability of suitable VLSI read-out electronics and reliable (and affordable) interconnect technology, ("flip-chip" bonding). Pixel detectors have also been studied more recently as imaging devices, particularly for X-rays in medical and non-destructive testing applications, and in synchrotron radiation beams. In the following, a description is given of the evolution and current state of development of pixel detectors for all of these applications. Reference is made to both monolith ic and hybrid semiconductor pixel detectors, considering not only silicon, (crystalline and amorphous), but also alternative semiconductor materials. The performance and limitations of current read-out electronics and bonding technology for hybrid detectors are discussed, together with the relative merits of charge integrating versus photon counting read-out for X-ray imaging applications. The paper concludes with an outline of potentially valuable future development possibilities

Active Detectors for Plasma Soft X-Ray Detection at PALS

This paper summarizes the work carried out for an experimental study of low-energy nuclear excitation by laser-produced plasma at the PALS Prague laser facility. We describe the adaptation and shielding of single-quantum active radiation detectors developed at IEAP CTU Prague to facilitate their operation inside the laser interaction chamber in the vicinity of the plasma target. The goal of this effort is direct real-time single-quantum detection of plasma soft X-ray radiation with energy above a few keV and subsequent identification of the decay of the excited nuclear states via low-energy gamma rays in a highly radiative environment with strong electromagnetic interference

Study of the charge sharing in a silicon pixel detector by means of α-particles interacting with a Medipix2 device

The energy deposited in a silicon detector by a heavy charged particle, such as an α-particle, creates a large number of electron–hole pairs. Under the influence of an electric field, the carriers drift towards the corresponding electrode. Due to diffusion, the charge carriers are spread. Lateral spreading depends on the collection time; hence it is expected to be smaller for larger fields. In the case of a pixellated detecting structure, this lateral spread can cause a sharing of the charge between the electrodes and many pixels will have a signal: that is, charge carriers generate a cluster of adjacent pixels. Also influencing the charge collection and its spread is the large concentration of electron–hole pairs generated locally by the α-particle, which creates distortions of the electric field along the ionizing path, giving rise to the so-called plasma and funnelling effects. The results of the charge-sharing effect measured in the Medipix2 pixel detectors are shown as a function of the α-particle energy and applied bias voltage. A model describing the effects of plasma and diffusion on the charge collection and charge sharing is presented