Focal-plane detector system for the KATRIN experiment Amsbaugh, J.F.; Barrett, J.; Beglarian, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2015, Letnik:
778, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid ...magnets, an ultra high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.
The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200
meV
/
c
2
(90% C. L.) by a precision measurement of the shape of the tritium
β
-spectrum in the endpoint ...region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software “Kassiopeia”, which was developed in the KATRIN collaboration over recent years.
Dead layer on silicon p–i–n diode charged-particle detectors Wall, B.L.; Amsbaugh, J.F.; Beglarian, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2014, Letnik:
744
Journal Article
Recenzirano
Odprti dostop
Semiconductor detectors in general have a dead layer at their surfaces that is either a result of natural or induced passivation, or is formed during the process of making a contact. Charged ...particles passing through this region produce ionization that is incompletely collected and recorded, which leads to departures from the ideal in both energy deposition and resolution. The silicon p-i-n diode used in the KATRIN neutrino-mass experiment has such a dead layer. We have constructed a detailed Monte Carlo model for the passage of electrons from vacuum into a silicon detector, and compared the measured energy spectra to the predicted ones for a range of energies from 12 to 20 keV. The comparison provides experimental evidence that a substantial fraction of the ionization produced in the "dead" layer evidently escapes by diffusion, with 46% being collected in the depletion zone and the balance being neutralized at the contact or by bulk recombination. The most elementary model of a thinner dead layer from which no charge is collected is strongly disfavored.
Pelvic soft tissue sarcomas are rare. Potentially curative resection remains challenging due to anatomical constraints of true pelvis and tumour spread through various anatomical hiatus. We sought to ...review the oncological outcomes of surgically managed cases at our centre and determine whether outcomes differ for patients with localised (limited to pelvis) versus extensive disease (with extra-pelvic extension).
Sixty-seven patients who underwent surgical resection with curative intent at the centre for primary, non-metastatic, WHO intermediate to high-grade soft tissue sarcoma of the true pelvis from January 2012 through January 2020 were analysed. Establishment of the extent of disease was made by review of pre-treatment imaging and surgical notes. Oncologic endpoints examined were resection margin, recurrence rate, disease-free and overall survival.
Rates of complete oncological resection and disease control were similar for tumours with localised or extensive disease. On logistic regression analysis, tumour grade, and a negative resection margin (R0) correlated with the risk of recurrence (p=<0.05). On further multinomial analysis, R0 resection was associated with improved local control, but not metastatic relapse (p = 0.003).
5-year local recurrence-free and distant metastasis-free survival were 61.3% and 67.1%, respectively. Five and 10-year overall survival were 64% and 36%, respectively. Age >50 years and high tumour grade were associated with a worse outcome (p < 0.05).
When potentially curative surgery is performed for pelvic sarcoma, disease-extent does not influence oncologic outcomes. While a complete oncologic resection determines the risk of local recurrence, tumour grade and metastatic relapse remain primary prognostic determinants for overall survival.
Bioadhesion and surface wettability are influenced by microscale topography. In the present study, engineered pillars, ridges and biomimetic topography inspired by the skin of fast moving sharks ...(Sharklet AF™) were replicated in polydimethylsiloxane elastomer. Sessile drop contact angle changes on the surfaces correlated well (R
2
= 0.89) with Wenzel and Cassie and Baxter's relationships for wettability. Two separate biological responses, i.e. settlement of Ulva linza zoospores and alignment of porcine cardiovascular endothelial cells, were inversely proportional to the width (between 5 and 20 μm) of the engineered channels. Zoospore settlement was reduced by ∼85% on the finer (ca 2 μm) and more complex Sharklet AF™ topographies. The response of both cell types suggests their responses are governed by the same underlying thermodynamic principles as wettability.
The Black Hills State University Underground Campus (BHUC) houses a low background counting facility on the 4850′ level of the Sanford Underground Research Facility. There are currently four ...ultra-low background, high-purity germanium detectors installed in the BHUC and it is anticipated four more detectors will be installed within a year. In total, the BHUC will be able to accommodate up to twelve detectors with space inside a class 1000 cleanroom, an automated liquid nitrogen fill system, on-site personnel assistance and other required utilities.
•The BHUC is a low background counting facility being developed at SURF.•Four detectors are installed in the BHUC and four more will arrive within the year.•In total, the BHUC will be able to accommodate up to twelve detectors.•BHUC users are forming a collaboration of low background counters to pool resources.•There is currently space available for new low background counters in the BHUC.
PDF
