The MuCap experiment at the Paul Scherrer Institute has measured the rate ${\Lambda }_S$ of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. ${\Lambda }_S$ is determined from the difference between the ${\mu }^{-}$ disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of $1.2\times {10}^{10}$ ${\mu }^{-}$ decays, from which we extract the capture rate ${\Lambda }_S=(714.9\pm {5.4}_{\mathrm{stat}}\pm {5.1}_{\mathrm{syst}}){\mathrm{s}}^{-1}$ and derive the proton’s pseudoscalar coupling $g_P(q_0^2=-0.88m_{\mu }^2)=8.06\pm 0.55$.

We report on a search for double beta decay of $$^{130}\hbox {Te}$$130Te to the first $$0^{+}$$0+ excited state of $$^{130}\hbox {Xe}$$130Xe using a $$9.8\,\hbox {kg}\cdot \hbox {yr}$$9.8kg·yr exposure of $$^{130}\hbox {Te}$$130Te collected with the CUORE-0 experiment. In this work we exploit different topologies of coincident events to search for both the neutrinoless and two-neutrino double beta decay modes. We find no evidence for either mode and place lower bounds on the half-lives: $$T^{0\nu }_{0^+_1}>7.9\cdot 10^{23}\hbox {yr}$$T01+0ν>7.9·1023yr and $$T^{2\nu }_{0^+_1}>2.4\cdot 10^{23}\hbox {yr}$$T01+2ν>2.4·1023yr ( $$90\%\,\hbox {CL}$$90%CL ). Combining our results with those obtained by the CUORICINO experiment, we achieve the most stringent constraints available for these processes: $$T^{0\nu }_{0^+_1}>1.4\cdot 10^{24}\hbox {yr}$$T01+0ν>1.4·1024yr and $$T^{2\nu }_{0^+_1}>2.5\cdot 10^{23}\hbox {yr}$$T01+2ν>2.5·1023yr ( $$90\%\,\hbox {CL}$$90%CL ).

Background/Objectives: This study aims to present a structured clinical workflow for offline adaptive Biology-guided Radiotherapy (BgRT) using the RefleXion X1 PET-linac system, addressing challenges introduced by inter-treatment anatomical and biological changes. Methods: We propose a decision tree offline adaptation framework based on real-time assessments of Activity Concentration (AC), Normalized Target Signal (NTS), and bounded dose-volume histogram (bDVH%) metrics. Three offline strategies were developed: (1) preemptive adaptation for minor changes, (2) partial re-simulation for moderate changes, and (3) full re-simulation for major anatomical or metabolic alterations. Two clinical cases demonstrating strategies 1 and 2 are presented. Results: The preemptive adaptation strategy was applied in a case with early tumor shrinkage, maintaining delivery parameters within acceptable limits while updating contours and dose distribution. In the partial re-Simulation case, significant changes in PET signal necessitated a same-day PET functional modeling session and plan re-optimization, effectively restoring safe deliverability. Both cases showed reduced target volumes and improved OAR sparing without additional patient visits or tracer injections. Conclusions: Offline adaptive workflows for BgRT provide practical solutions to address inter-fractional changes in tumor structure and function. These strategies can help maintain the safety and accuracy of BgRT delivery and support clinical adoption of PET-guided radiotherapy, paving the way for future online adaptive capabilities.

CUORE is a cryogenic detector that will be operated at LNGS to search for neutrinoless double beta decay (0νββ) of ¹³⁰Te. The detector installation was completed in summer 2016. Before the installation, several cold runs were done to test the cryogenic system performance. In the last cold run the base temperature of 6.3 mK was reached in stable condition. CUORE-0, a CUORE prototype, has proven the feasibility of CUORE, demonstrating that the target background of 0.01 counts/keV/kg/y and the energy resolution of 5 keV are within reach.

Objectives. The purpose of this study is to present data from the clinical commissioning of an Xstrahl 150 x-ray unit used for superficial radiotherapy, Methods. Commissioning tasks included vendor acceptance tests, timer reproducibility, linearity and end-effect measurements, half-value layer (HVL) measurements, inverse square law verification, head-leakage measurements, and beam output calibration. In addition, percent depth dose (PDD) curves were determined for different combinations of filter/kV settings and applicators. Automated PDD water phantom scans were performed utilizing four contemporary detectors: a microDiamond detector, a microSilicon detector, an EDGE detector, and a PinPoint ionization chamber. The measured PDD data were compared to the published values in BJR Supplement 25, Results. The x-ray unit’s mechanical, safety, and radiation characteristics were within vendor-stated specifications. Across sixty commissioned x-ray beams, the PDDs determined in water using solid state detectors were in excellent agreement with the BJR 25 data. For the lower (<100 kVp) and medium-energy (≥100 kVp) superficial beams the average agreement was within [−3.6,+0.4]% and [−3.7,+1.4]% range, respectively. For the high-energy superficial (low-energy orthovoltage) x-rays at 150 kVp, the average difference for the largest 20 × 20 cm² collimator was (−0.7 ± 1.0)%, Conclusions. This study presents machine characterization data collected for clinical use of a superficial x-ray unit. Special focus was placed on utilizing contemporary detectors and techniques for the relative PDD measurements using a motorized water phantom. The results in this study confirm that the aggregate values published in the BJR 25 report still serve as a valid benchmark when comparing data from site-specific measurements, or the reference data for clinical utilization without such measurements, Advances in knowledge. This paper presents comprehensive data from the acceptance and commissioning of a modern kilovoltage superficial x-ray radiotherapy machine. Comparisons between the PDD data measured in this study using different detectors and BJR 25 data are highlighted.

SciPost Journals Publication Detail SciPost Phys. 12, 015 (2022) Comment on Coleman-DeLuccia instantons