Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

The MAJORANA DEMONSTRATOR for 0νββ: Current Status and Future Plans

The MAJORANA DEMONSTRATOR will search for neutrinoless-double-beta decay (0νββ) in 76Ge, while establishing the feasibility of a future tonne-scale germanium-based 0νββ experiment, and performing searches for new physics beyond the Standard Model. The experiment, currently under construction at the Sanford Underground Research Facility in Lead, SD, will consist of a pair of modular high-purity germanium detector arrays housed inside of a compact copper, lead, and polyethylene shield. Through a combination of strict materials qualifications and assay, low-background design, and powerful background rejection techniques, the Demonstrator aims to achieve a background rate in the 0νββ region of interest (ROI) of no more than 3 counts in the 0νββ-decay ROI per tonne of target isotope per year (cnts/(ROI-t-y)). The current status of the Demonstrator is discussed, as are plans for its completion

A Dark Matter Search with MALBEK

The Majorana Demonstrator is an array of natural and enriched high purity germanium detectors that will search for the neutrinoless double-beta decay of 76Ge and perform a search for weakly interacting massive particles (WIMPs) with masses below 10 GeV. As part of the Majorana research and development efforts, we have deployed a modified, low-background broad energy germanium detector at the Kimballton Underground Research Facility. With its sub-keV energy threshold, this detector is sensitive to potential non-Standard Model physics, including interactions with WIMPs. We discuss the backgrounds present in the WIMP region of interest and explore the impact of slow surface event contamination when searching for a WIMP signal

The Majorana Demonstrator: Progress towards showing the feasibility of a tonne-scale 76Ge neutrinoless double-beta decay experiment

The Majorana Demonstrator will search for the neutrinoless double-beta decay (0vββ) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a low-background environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 t-1 y-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0vββ [1]; and performing a direct search for light WIMPs (3-10 GeV/c2)

The MAJORANA experiment: An ultra-low background search for neutrinoless double-beta decay

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the MAJORANA experiment, known as the DEMONSTRATOR, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak

Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein

Search for Neutrinoless Double- β Decay in Ge 76 with the Majorana Demonstrator

The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in Ge76. The Majorana Demonstrator comprises 44.1 kg of Ge detectors (29.7 kg enriched in Ge76) split between two modules contained in a low background shield at the Sanford Underground Research Facility in Lead, South Dakota. Here we present results from data taken during construction, commissioning, and the start of full operations. We achieve unprecedented energy resolution of 2.5 keV FWHM at Qββ and a very low background with no observed candidate events in 9.95 kg yr of enriched Ge exposure, resulting in a lower limit on the half-life of 1.9×1025 yr (90% C.L.). This result constrains the effective Majorana neutrino mass to below 240-520 meV, depending on the matrix elements used. In our experimental configuration with the lowest background, the background is 4.0-2.5+3.1 counts/(FWHM t yr)

Experimental investigation of a flow monitoring instrument in an upper plenum of an air-water reflood test facility. [PWR]

Instrumentation was developed for measuring fluid phenomena in the upper plenum of pressurized water reactor reflood facilities. In particular, the instrumentation measured two-phase flow velocity and void fraction. The principle of operation of the instrumentation scheme was based on the measurement of electrical impedance. The technique of analysis of random signals from two spatially separated impedance sensors was employed to measure two-phase flow velocity. A relative admittance technique was used to determine void fraction. The performance of the instrumentaton was studied in an air-water test facility

Early and late toxicity profiles of patients receiving immediate postoperative radiotherapy versus salvage radiotherapy for prostate cancer after prostatectomy.

PurposeThe present study aims to evaluate both early and late toxicity profiles of patients receiving immediate postoperative radiotherapy (RT; adjuvant RT or additive RT) compared to salvage RT.MethodsWe evaluated 253patients with prostate cancer treated with either immediate postoperative (adjuvant RT, n=42; additive RT, n=39) or salvage RT (n=137). Thirty-five patients received salvage treatment but did not achieve apostoperative prostate specific antigen (PSA) level <0.1ng/ml and thus were excluded from analysis.ResultsAsignificantly higher rate of early grade1/2 proctitis in the immediate postoperative RT group without additional pelvic RT was observed (p=0.02). Patients in the immediate postoperative RT group without additional pelvic RT showed significantly more early urinary tract obstructions (p=0.003). Toxicity rates of early (<3months) and late (3-6months) postoperative RT were similar (p>0.05). Baseline recovery rate of erectile dysfunction was better in patients with immediate postoperative RT without additional pelvic RT (p=0.02; hazard ratio (HR)=2.22, 95%-confidence interval, 95%-CI: 1.12-4.37). Recovery rate of urinary incontinence showed no significant difference in all groups (p>0.05).ConclusionPatients receiving immediate postoperative RT (adjuvant or additive RT) without additional pelvic RT experience early gastrointestinal (GI) side effect proctitis and, as well as early genitourinary (GU) toxicity urinary tract obstruction more frequently than patients treated with salvage RT. Therefore, complete recovery after surgery is essential. However, we suggest basing the treatment decision on the patient's postoperative clinical condition and evaluation of any adverse risk factors, since many studies demonstrate aclear benefit for immediate postoperative RT (adjuvant or additive RT) in terms of oncological outcome. ZusammenfassungHintergrundIn der vorliegenden Auswertung werden die fruhen und spaten Nebenwirkungen der sofortigen postoperativen Radiotherapie (RT; adjuvante oder additive RT) mit der Salvage-RT verglichen.MethodenDie Autoren werteten die Daten von 253Patienten mit Prostatakarzinom aus, welche mit sofortiger postoperativer RT behandelt wurden: n=42 fur adjuvante RT, n=39 fur additive RT, n=137 fur Salvage-RT. Die 35mit einer Salvage-Therapie behandelten Patienten, die keinen postoperativen Nadir fur das prostataspezifische Antigen (PSA) <0,1ng/ml erreichten, wurden aus der Analyse ausgeschlossen.ErgebnissePatienten mit sofortiger postoperativer RT ohne zusatzliche RT des Beckens zeigten eine signifikant hohere Rate an fruhen Grad-1/2-Proktitiden (p=0,02). Au ss erdem wies diese Gruppe signifikant mehr fruhe obstruktive Uropathien auf (p=0,003). Es gab keinen signifikanten Unterschied (p>0,05) bezuglich der Nebenwirkungsprofile zwischen Patienten mit fruher postoperativer RT (innerhalb <3Monate) vs. spate postoperative RT (innerhalb von 3-6Monaten). Die Post-RT-Ruckbildungsrate der erektilen Dysfunktion war signifikant besser bei Patienten mit sofortiger postoperativer RT ohne zusatzliche RT des Beckens (p=0,02; Hazard Ratio, HR=2,22; 95%-Konfidenzintervall, 95%-KI: 1.12-4,37). Dagegen wies die Ruckbildungsrate einer Harninkontinenz keine signifikanten Unterschiede in allen Gruppen auf (p>0,05).SchlussfolgerungBei Patienten mit sofortiger postoperativer RT (adjuvante oder additive RT) ohne zusatzliche RT des Beckens treten haufiger fruhe gastrointestinale Nebenwirkungen wie Proktitis auf. Ebenso leiden sie haufiger an obstruktiven Uropathien.Eine komplette postoperative Erholung von Nebenwirkungen ist deswegen wichtig. Die Autoren empfehlen daher, die Therapieentscheidung mit Blick auf den postoperativen Zustand des Patienten und vorhandene Risikofaktoren fur ein Rezidiv zu treffen, denn manche Tumorfaktoren machen eine aggressive Vorgehensweise notwendig