A compact high resolution pair spectrometer for photons at intermediate energies

The physics reach and feasibility of the Future Circular Collider are currently being investigated in the form of a Conceptual Design Report. The ultimate goal is to collide protons with a centre-of-mass energies of 100 TeV, thus extending the reach of the current HEP facilities. This high-energy regime opens new opportunities for the discovery of physics beyond the standard model, but also new constraints on the detector design. As at 100 TeV a large fraction of the W, Z, H bosons and top quarks are produced with a significant boost, it implies an efficient reconstruction of high energetic objects. The reconstruction of those boosted objects sets the calorimeter performance requirements in terms of energy resolution, containment of highly energetic hadron showers, and high transverse granularity. The detectors designed for the FCC experiments need to tackle harsh conditions of the unprecedented collision energy and instantaneous luminosity. They also must be able to deal with a very high number of collisions per bunch crossings (pile-up). Excellent energy and angular resolution, also for low energetic particles, is therefore needed in order to meet the demands based on the physics benchmarks like Higgs self-couplings. We present the current baseline technologies for the calorimeter system of the FCC-hh reference detector and present first results of the performance studies with the combined calorimeters, meeting the energy resolution goal.

The motion of electrons and positrons was modeled in a spectrometer based on a constant magnetic dipole and their subsequent detection in position-sensitive silicon detectors. The electron and positron emission energy and angle resolutions were obtained. The spectrometer is a part of setup for studying rare intranuclear processes in light nuclei with the production of internal conversion pairs.

Optimal design of waveform digitisers for both energy resolution and pulse shape discrimination

The focusing and overfocusing of atoms sputtered from Ni (001) face are studied with the use of molecular dynamics computer simulations. When a crystal transitions from the paramagnetic to the ferromagnetic state, there is a reduction in the number of focused and overfocused sputtered atoms. The evolution of distributions of sputtered atoms with the simultaneous energy and polar angle resolution due to changes in the azimuthal angle and binding energy of atoms at a surface is studied.

Front-end electronics of the ALICE photon spectrometer

Performance evaluation of newly developed SrI2(Eu) scintillator

Compact high-resolution X-ray spectrometers with a one-dimensional temperature gradient at the analyzer crystal are considered. This gradient, combined with the use of a position-sensitive detector, makes it possible to relax the usual Rowland-circle condition, allowing increased space at the sample position for a given energy resolution or arm radius. Thus, for example, it is estimated that approximately meV resolution is possible with a 3 m analyzer arm and 200 mm clearance between the sample and detector. Simple analytic formulae are provided, supported by excellent agreement with ray-tracing simulations. One variation of this method also allows the detector position sensitivity to be used to determine momentum transfer, effectively improving momentum resolution without reducing (slitting down) the analyzer size. Application to medium-resolution ( approximately 10-100 meV) inelastic X-ray scattering spectrometers with large angular acceptance is discussed, where this method also allows increased space at the sample. In some cases the application of a temperature gradient can improve the energy resolution even with a single-element detector.

The next-generation of neutrinoless double beta decay (0νββ) searches are targeting half-life sensitivities towards 1027–1028 years. Gaseous xenon time projection chamber (GXeTPC) detectors may be able to meet this challenge due to their excellent energy resolution and background rejection power through event visualization. This paper explores how the design choices of a next-generation GXeTPC time projection chamber can impact the overall performance of the experiment. We study the performance of systems using xenon enriched in the isotope 136Xe or natural xenon, focusing on scenarios that incorporate one tonne of 136Xe isotope. The detector size, copper shielding mass, energy resolution, density (using pressure at 293 K for convenience), and corresponding levels of diffusion are surveyed to evaluate the overall performance dependencies on these parameters. A detector optimized for using enriched xenon is preferred over natural, due primarily to a factor of 10 lower background rate driven by the large intrinsic backgrounds introduced by the copper shielding used in the detector. The performance of three types of gas TPC technologies was also explored based on different gas additives used to reduce diffusion to different levels. For all TPC technologies, we find background rates of a fraction of a count per tonne year in the region of interest are achievable. These performance levels are contingent on suitable energy resolution and event position placement in the drift direction being achieved for the specific detector technology. Performance for enriched xenon TPCs varies mildly with pressure in the range 5 to 25 bars, reaching background levels below 0.2 events/tonne-year. Performance at one bar is worse by approximately a factor of four. When considerations for the construction of the detector in addition to the selection performance are included, there may be no clearly optimum pressure.

Fabrication and characterization of cubic SrI2(Eu) scintillators for use in array detectors

Scintillators are important materials for radiation detection applications such as homeland security, geological exploration, and medical imaging. Scintillators for nuclear nonproliferation applications in particular must have excellent energy resolution in order to distinguish the gamma-ray signatures of potentially dangerous radioactive sources, such as highly enriched uranium or plutonium, from non-threat radioactive sources such as radioactive tracers used in medical imaging. There is an established need for scintillators with energy resolution in the 1-2% range at 662 keV. However, there are challenges surrounding the development of this new generation of high light yield/high resolution scintillators; for example, the high cost of production due to low crystal yield and slow growth process, and crystal inhomogeneity. We will discuss efforts focused on developing recently discovered high performance scintillators K(Sr,Ba)2I5:Eu, Cs4(Ca,Sr)I6:Eu and Cs2Hf(Cl,Br)6 that have potential for meeting nuclear security needs. Growth parameters for these materials have been optimized, allowing the growth of excellent quality single crystals measuring up to one-inch in diameter via the vertical Bridgman technique at translation rates between 1 and 5 mm/h. These scintillators materials have excellent properties with light yields between 30,000 and 120,000 ph/MeV, and energy resolutions between 2.3 and 4.6% at 662 keV.

A silicon multi-cathode detector (SMCD) has been developed for microanalysis and x-ray mapping applications. The SMCD has a large active area (∼0.5 cm2), excellent energy resolution, and high count rate capability. The detector utilizes novel structures that have produced very low dark current, high electric field, uniform charge collection, low noise and high sensitivity to low energy x-rays. The detector's spectral response was evaluated using a 55Fe radioisotope source, as well as by fluorescing materials with an x-ray generator. Figure 1 shows a 55Fe spectrum with an energy resolution of 125 eV FWHM at 5.9 keV collected at 12 μs peaking time. This energy resolution has been repeatably measured on many different detectors. To evaluate the high count rate x-ray performance, which is very important for fast x-ray mapping, a Cu sample was fluoresced using a Rh-anode x-ray tube.

Integrated photonic crystal spectrometers for sensing applications

A magnetic proton recoil (MPR) spectrometer is a novel instrument with superior performance, including high energy resolution, high count rate and good signal-to-noise ratio (SNR) for measurements of neutron spectra from inertial confinement fusion (ICF) experiments and high power Tokomaks. In this work, the design of a compact MPR spectrometer (cMPR) was evaluated for deuteron-tritium (DT) neutron spectroscopy. The characteristics of the spectrometer were analyzed using 2-D beam transport simulations, 3-D particle transport calculations and Monte-Carlo simulations. Based on the theoretical results, an instrument design that satisfies special experimental requirements is proposed. The energy resolution and efficiency of the spectrometer are also evaluated. The results indicate that the proposed cMPR spectrometer would achieve a detection efficiency and energy resolution of approximately 10−8 and 4%, respectively, for DT neutrons.

The use of Thin-foil Proton Recoil (TPR) spectrometers to measure neutrons from Deuterium-Tritium (DT) fusion plasma has been studied previously and is a well established technique for neutron spectrometry. The study presented here focuses on the optimisation of the TPR spectrometer configurations consisting of Δ E and E silicon detectors. In addition an investigation of the spectrometer's ability to determine fuel ion temperature and fuel ion density ratio in ITER like DT plasmas has been performed.A Python code was developed for the purpose of calculating detection efficiency and energy resolution as a function of several spectrometer geometrical parameters. An optimisation of detection efficiency for selected values of resolution was performed regarding the geometrical spectrometer parameters using a multi-objective optimisation, a.k.a. Pareto plot analysis. Moreover, the influence of detector segmentation on spectrometer energy resolution and efficiency was investigated. The code also produced response functions for the two selected spectrometer configurations. The SPEC code was used to simulate the spectrometer's performance in determining the fuel ion temperature and fuel ion density ratio nt/nd.The results presented include the selected spectrometer configuration with calculated energy resolution and efficiency. For a selected spectrometer resolution of 5% a maximum efficiency of around 0.003% was achieved. Moreover, the detector segmentation allows for a 20% increase in spectrometer efficiency for an energy resolution of 4.3%. The ITER requirements for a 20% accuracy on the nt/nd ratio determination and 10% on the temperature determination within a 100 ms sampling window can be achieved using a combination of several TPR's of same type, in order to boost efficiency.

In the Large Hadron Collider collisions between protons and between lead nuclei will occur in which the impact parameter will be greater than the sum of the radii of the colliding partners, ultra-peripheral collisions (UPC's). A novel detector (the ATLAS Zero Degree Calorimeter, ZDC) has been constructed to selectively trigger on such collisions. It detects extremely forward neutrons that are emitted from the projectile/target by photons via a dipole excitation. Cerenkov light, generated by showers in tungsten plates, is funneled to photomultiplier tubes via quartz fibers. The detector has excellent timing and energy resolution.