Thermal simulations of temperature excursions on the Athena X-IFU detector wafer from impacts by cosmic rays

We present the design and implementation of a thermal model, developed in COMSOL, aiming to probe the wafer-scale thermal response arising from realistic rates and energies of cosmic rays at L2 impacting the detector wafer of Athena X-IFU. The wafer thermal model is a four-layer 2D model, where 2 layers represent the constituent materials (Si bulk and Si$_{3}$N$_{4}$ membrane), and 2 layers represent the Au metallization layer's phonon and electron temperatures. We base the simulation geometry on the current specifications for the X-IFU detector wafer, and simulate cosmic ray impacts using a simple power injection into the Si bulk. We measure the temperature at the point of the instrument's most central TES detector. By probing the response of the system and pulse characteristics as a function of the thermal input energy and location, we reconstruct cosmic ray pulses in Python. By utilizing this code, along with the results of the GEANT4 simulations produced for X-IFU, we produce realistic time-ordered data (TOD) of the temperature seen by the central TES, which we use to simulate the degradation of the energy resolution of the instrument in space-like conditions on this wafer. We find a degradation to the energy resolution of 7 keV X-rays of $\approx$0.04 eV. By modifying wafer parameters and comparing the simulated TOD, this study is a valuable tool for probing design changes on the thermal background seen by the detectors.Comment: accepted for publication in the Journal of Low Temperature Physic

Characteristics, management and outcome of prehospital pediatric emergencies by a Dutch HEMS

Background: In prehospital care, the Helicopter Emergency Medical Service (HEMS) can be dispatched for critically injured or ill children. However, little detail is known about dispatches for children, in terms of the incidence of prehospital interventions and overall mortality. The primary objective of this study is to provide an overview of pediatric patient characteristics and incidence of interventions. Methods: A retrospective chart review of all patients ≤ 17 years who received medical care by Rotterdam HEMS from 2012 until 2017 was carried out. Results: During the study period, 1905 pediatric patients were included. 59.1% of patients were male and mean age was 6.1 years with 53.2% of patients aged ≤ 3 years. 53.6% were traumatic patients and 49.7% were non-traumatic patients. 18.8% of patients were intubated. Surgical procedures were performed in 0.9%. Medication was administered in 58.1% of patients. Cardiopulmonary resuscitation (CPR) was necessary in 12.9% of patients, 19.9% were admitted to the intensive care unit and 14.0% needed mechanical ventilation. Overall mortality was 9.5%. Mortality in trauma patients was 5.5% and in non-trauma group 15.3%. 3.9% of patients died at the scene. Conclusions: Patients attended by HEMS are at high risk of prehospital interventions like CPR or intubation. EMS has little exposure to critically ill or injured children. Hence, HEMS expertise is required to perform critical procedures. Trauma patients had higher survival rates than non-traumatic patients. This may be explained by underlying illnesses in non-traumatic patients and CPR as reason for dispatch. Further research is needed to identify options for improving prehospital care in the non trauma pediatric patients

The high energy Universe at ultra-high resolution: the power and promise of X-ray interferometry

We propose the development of X-ray interferometry (XRI), to reveal the Universe at high energies with ultra-high spatial resolution. With baselines which can be accommodated on a single spacecraft, XRI can reach 100 μ as resolution at 10 Å (1.2 keV) and 20 μ as at 2 Å (6 keV), enabling imaging and imaging-spectroscopy of (for example) X-ray coronae of nearby accreting supermassive black holes (SMBH) and the SMBH ‘shadow’; SMBH accretion flows and outflows; X-ray binary winds and orbits; stellar coronae within ∼100 pc and many exoplanets which transit across them. For sufficiently luminous sources XRI will resolve sub-pc scales across the entire observable Universe, revealing accreting binary SMBHs and enabling trigonometric measurements of the Hubble constant with X-ray light echoes from quasars or explosive transients. A multi-spacecraft ‘constellation’ interferometer would resolve well below 1 μ as, enabling SMBH event horizons to be resolved in many active galaxies and the detailed study of the effects of strong field gravity on the dynamics and emission from accreting gas close to the black hole