Full Commissioning Research Articles

Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)

The National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand, and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabilities that will accompany full commissioning of the five facility instruments. With this Critical Science Plan (CSP) we attempt to anticipate some of what those capabilities will enable, providing a snapshot of some of the scientific pursuits that the DKIST hopes to engage as start-of-operations nears. The work builds on the combined contributions of the DKIST Science Working Group (SWG) and CSP Community members, who generously shared their experiences, plans, knowledge, and dreams. Discussion is primarily focused on those issues to which DKIST will uniquely contribute.

Achievements and lessons learned from the operation of KSTAR plasma control system upgrade

Results on the integration and the operation of the KSTAR plasma control system (PCS) upgrade are given. Real-time hardware, new realtime-capable operating system, and a brand-new data acquisition are assembled in order to extend the performance and compatibility with modern computer systems. The first full commissioning and eventual routine use performed in 2016 so that the system can now acquire more than 400 channels for more than 100 seconds of data with 5 kHz sampling. The performance test results are summarized, featuring In/Out streaming echo tests and the synchronization verifications. Examples of general performance improvements are demonstrated, and additional features added to the software are also described.

SPECTIX, a PETAL+ X-ray spectrometer: design, calibration and preliminary tests

The present article describes the design, the calibration and preliminary tests of the X-ray transmission crystal spectrometer SPECTIX (Spectromètre PEtal à Cristaux en Transmission X) built in the framework of the PETAL (PETawatt Aquitaine Laser) project and located in the Laser MégaJoule (LMJ) facility [1,2]. SPECTIX aims at characterizing the hard x-ray Kα emission generated by the interaction of the PETAL ps ultra high-energy laser with a target. The broad spectral range covered by this spectrometer (7 to 150 keV) is achieved by using two measurement channels composed by two distinct crystals. Due to the harsh environment experienced by the spectrometer during a LMJ-PETAL shot, passive detection with image plates is used. Shielding has been dimensioned in order to protect the detector against PETAL shot products. It includes a magnetic dipole to remove electrons entering the spectrometer, a 20 mm thick tungsten frontal collimation and a 6 mm thick lead housing. The SPECTIX performances, including the shielding efficiency, have been tested during an experimental campain performed at the PICO 2000 laser facility at LULI. Improvements inferred from these tests are currently being implemented. Full commissioning of SPECTIX is planned on PETAL shots at the end of 2017.

Advanced electron cyclotron heating and current drive experiments on the stellarator Wendelstein 7-X

During the first operational phase (OP 1.1) of Wendelstein 7-X (W7-X) electron cyclotron resonance heating (ECRH) was the exclusive heating method and provided plasma start-up, wall conditioning, heating and current drive. Six gyrotrons were commissioned for OP1.1 and used in parallel for plasma operation with a power of up to 4.3 MW. During standard X2-heating the spatially localized power deposition with high power density allowed controlling the radial profiles of the electron temperature and the rotational transform. Even though W7-X was not fully equipped with first wall tiles and operated with a graphite limiter instead of a divertor, electron densities of n e > 3·1019 m-3 could be achieved at electron temperatures of several keV and ion temperatures above 2 keV. These plasma parameters allowed the first demonstration of a multipath O2-heating scenario, which is envisaged for safe operation near the X-cutoff-density of 1.2·1020 m-3 after full commissioning of the ECRH system in the next operation phase OP1.2.

Denoising of gravitational wave signals via dictionary learning algorithms

Gravitational wave astronomy has become a reality after the historical detections accomplished during the first observing run of the two advanced LIGO detectors. In the following years, the number of detections is expected to increase significantly with the full commissioning of the advanced LIGO, advanced Virgo and KAGRA detectors. The development of sophisticated data analysis techniques to improve the opportunities of detection for low signal-to-noise-ratio events is hence a most crucial effort. We present in this paper one such technique, dictionary-learning algorithms, which have been extensively developed in the last few years and successfully applied mostly in the context of image processing. However, to the best of our knowledge, such algorithms have not yet been employed to denoise gravitational wave signals. By building dictionaries from numerical relativity templates of both, binary black holes mergers and bursts of rotational core collapse, we show how machine-learning algorithms based on dictionaries can be also successfully applied for gravitational wave denoising. We use a subset of signals from both catalogs, embedded in non-white Gaussian noise, to assess our techniques with a large sample of tests and to find the best model parameters. The application of our method to the actual signal GW150914 shows promising results. Dictionary-learning algorithms could be a complementary addition to the gravitational wave data analysis toolkit. They may be used to extract signals from noise and to infer physical parameters if the data are in good enough agreement with the morphology of the dictionary atoms.

TH‐AB‐201‐10: Portal Dosimetry with Elekta IViewDose:Performance of the Simplified Commissioning Approach Versus Full Commissioning

Purpose:Elekta recently developed a solution for in‐vivo EPID dosimetry (iViewDose, Elekta AB, Stockholm, Sweden) in conjunction with the Netherlands Cancer Institute (NKI). This uses a simplified commissioning approach via Template Commissioning Models (TCMs), consisting of a subset of linac‐independent pre‐defined parameters. This work compares the performance of iViewDose using a TCM commissioning approach with that corresponding to full commissioning. Additionally, the dose reconstruction based on the simplified commissioning approach is validated via independent dose measurements.Methods:Measurements were performed at the NKI on a VersaHD™ (Elekta AB, Stockholm, Sweden). Treatment plans were generated with Pinnacle 9.8 (Philips Medical Systems, Eindhoven, The Netherlands). A farmer chamber dose measurement and two EPID images were used to create a linac‐specific commissioning model based on a TCM. A complete set of commissioning measurements was collected and a full commissioning model was created.The performance of iViewDose based on the two commissioning approaches was compared via a series of set‐to‐work tests in a slab phantom. In these tests, iViewDose reconstructs and compares EPID to TPS dose for square fields, IMRT and VMAT plans via global gamma analysis and isocentre dose difference. A clinical VMAT plan was delivered to a homogeneous Octavius 4D phantom (PTW, Freiburg, Germany). Dose was measured with the Octavius 1500 array and VeriSoft software was used for 3D dose reconstruction. EPID images were acquired. TCM‐based iViewDose and 3D Octavius dose distributions were compared against the TPS.Results:For both the TCM‐based and the full commissioning approaches, the pass rate, mean γ and dose difference were >97%, <0.5 and <2.5%, respectively. Equivalent gamma analysis results were obtained for iViewDose (TCM approach) and Octavius for a VMAT plan.Conclusion:iViewDose produces similar results with the simplified and full commissioning approaches. Good agreement is obtained between iViewDose (simplified approach) and the independent measurement tool.This research is funded by Elekta Limited

Multi‐institutional dosimetric and geometric commissioning of image‐guided small animal irradiators

To compare the dosimetric and geometric properties of a commercial x-ray based image-guided small animal irradiation system, installed at three institutions and to establish a complete and broadly accessible commissioning procedure. The system consists of a 225 kVp x-ray tube with fixed field size collimators ranging from 1 to 44 mm equivalent diameter. The x-ray tube is mounted opposite a flat-panel imaging detector, on a C-arm gantry with 360° coplanar rotation. Each institution performed a full commissioning of their system, including half-value layer, absolute dosimetry, relative dosimetry (profiles, percent depth dose, and relative output factors), and characterization of the system geometry and mechanical flex of the x-ray tube and detector. Dosimetric measurements were made using Farmer-type ionization chambers, small volume air and liquid ionization chambers, and radiochromic film. The results between the three institutions were compared. At 225kVp, with 0.3 mm Cu added filtration, the first half value layer ranged from 0.9 to 1.0 mm Cu. The dose-rate in-air for a 40 × 40 mm(2) field size, at a source-to-axis distance of 30 cm, ranged from 3.5 to 3.9 Gy/min between the three institutions. For field sizes between 2.5 mm diameter and 40 × 40 mm(2), the differences between percent depth dose curves up to depths of 3.5 cm were between 1% and 4% on average, with the maximum difference being 7%. The profiles agreed very well for fields >5 mm diameter. The relative output factors differed by up to 6% for fields larger than 10 mm diameter, but differed by up to 49% for fields ≤5 mm diameter. The mechanical characteristics of the system (source-to-axis and source-to-detector distances) were consistent between all three institutions. There were substantial differences in the flex of each system. With the exception of the half-value layer, and mechanical properties, there were significant differences between the dosimetric and geometric properties of the three systems. This underscores the need for careful commissioning of each individual system for use in radiobiological experiments.

SU-E-P-01: Project Schedule for Commissioning of a Synchrotron Based Modulated Scanning Proton Therapy Machine

Purpose: The commissioning of a modulated scanning proton machine, CBCT imaging system, and robotic couch is a challenging project. A coordinated project plan can reduce the required time to commission the system and help facilitate the coordination of work both among physics and with other teams. We have proposed a schedule, listing underlying assumptions, which would accomplish this efficiently. Methods: We used Microsoft Project to create several alternative commissioning schedules for comparison. The commissioning team of five physicists was divided into multiple teams so that work could be accomplished either in parallel or staggered shifts as necessary. Alternative commissioning schedules included a full commissioning of all available energies and options as well as a project plan focused mainly for prostate treatments. Project subsections were grouped so that modifications for changes in project scope or other assumptions could be made easily. Results: The project schedule for full commissioning had a duration of approximately 85 working days while commissioning time for only prostate treatments was 57 days. Detailed beam time requirements and sub‐section completion dates provided necessary information for engineering and other related teams. Time savings in the project schedule was realized in several ways. Staggered shifts were utilized to increase the efficiency in beam measurement time while still allowing for extended working time, splitting shifts if increase in beam time is available. Conclusion: The creation of the project plan has allowed us to have a realistic estimate of the time required to complete the commissioning project along with a list of assumptions made in creating the schedule. This provides a means to track our progress towards completion, quickly assess the impact of any changes to the schedule or difficulties that happen during commissioning, and easily communicate these to interested parties.

SU‐E‐T‐424: Clinical Validation of a GammaBeam Tomotherapy System Using the Octavius Pre‐Treatment QA Device

Purpose: Verify and validate the clinical viability of a GammaBeam Tomotherapy system Methods: A full commissioning of the GammaBeam Tomotherapy unit is performed. This novel radiotherapy system integrates the Co‐60 Equinox machine (Best Theratronics, Canada), MIMiC MLC, AutoCrane and nomoSTATM software (Best Nomos, PA). PDDs, output factors and profiles was acquired and entered into the Corvus GammaBeam treatment planning system. Patient treatment plans for H&N, Pelvis, Brain and Brain SRS were generated. Corresponding pre‐treatment QA plans were calculated and delivered on the Octavius QA phantom (PTW, NY). As acceptance criteria, we applied a gamma analysis with a DTA ranging from 3 mm to 5 mm and a dose difference from 1% to 4% (of local dose). Plan quality is also analyzed in terms of target coverage, organ at risk sparing, skin dose, hot spots, etc., in comparison to serial tomotherapy plans generated on the same CT sets using linac based photon beams. Results: for the H&N plan, acceptance criteria were set to 4%, 5 mm DTA to meet the minimum requirement of more than 90% of points passing. For the Pelvis, 91.6% of points pass the 3%, 3 mm DTA. For Brain and Brain SRS, a gamma analysis based on 2%, 2 mm DTA resulted in 98% and 90.9% of points passing. In the most complex case of H&N, constraints were met with 10% hot spot (within the target) and a skin dose ∼50% of the prescribed dose. Conclusions: investigation has demonstrated that the GammaBeam Tomotherapy system is clinically viable. At maximum source activity (∼15000 Ci), a 2 Gy fraction of the H&N plan took 20 minutes to deliver. Although this time is expected to slowly increase, due to source decay, to reach ∼30 minutes three years later, it remains comparable to linac based tomotherapy treatment times.Financial support for this work was obtained from Best Medical International.

WE-C-BRA-06: The VERO System, a Novel IGRT Device for Stereotactic Body Radiation Therapy: Commissioning and First Experience

Purpose: Due to the recent introduction of the VERO system in the field, very little detailed information is available. An overview will be given of the experimental results acquired during commissioning. Methods and Materials: The VERO system, a novel radiation therapy platform developed for image guided stereotactic body radiotherapy (SBRT), has been installed and commissioned in our hospital. This device is a joint product of BrainLAB and MHI. A newly developed small 6 MV linac with attached MLC is mounted on an O-ring gantry. The MLC consists of 60 5-mm-leafs and produces a maximum field size of 150×150mm. The gantry rotates 360° about the horizontal axis, similar to a C-arm linac platform, but additionally allows rotation about the vertical axis, a so called “skew” of +/− 60°. Orthogonal gimbals hold the linac, which allows pan and tilt motions of the linac and the therapeutic beam. This mechanism offers the possibility to actively compensate for mechanical distortions during gantry rotation and to perform real-time tracking of moving tumors. Beside an EPID for MV portal imaging, the system is equipped with a dual orthogonal kV Imaging systems attached to the O-ring at 45° from the MV beam. This imaging system allows simultaneous acquisition of orthogonal X-rays images and fluoroscopy. Also kV cone-beam CT imaging is available. An automated infra-red marker based patient-positioning device is integrated. The treatment couch provides 5D positional correction (X,Y,Z,pitch,roll). The 6th degree of freedom, the yaw angle correction, is handled by the O-ring skew. Results: We have conducted full commissioning of this novel SBRT platform, including full mechanical and dosimetric characterization, and report on the performance of this device installed in a clinical environment. Conclusion: Based on the experimental results, the systems characteristics were considered adequate for SBRT treatments. Conflict of Interest: Research sponsored by BrainLAB.

Calibration of the barrel muon drift tubes system in CMS

In this report, results on the calibration process of the Drift Tubes (DT) system of the Compact Muon Solenoid experiment are presented. The full commissioning of the calibration procedure has been deployed in year 2008 with the CMS Computing, Software and Analysis challenge (CSA08), which has tested the full work-flow needed for CMS data-taking during the LHC start-up operations. In autumn 2008, the same Calibration work-flow was applied to a high statistics cosmic ray muon data taking period: the Cosmic Run At Four Tesla (CRAFT) period. The accurate measurement of the main calibration conditions corresponding to the Time Pedestals and the Drift Velocity provide the necessary space-time relationship used in the first stage of the muon local reconstruction.

SSRF in Full Commissioning

The focus of the Shanghai Synchrotron Radiation Facility (SSRF), funded jointly by the Central Government of China, Chinese Academy of Sciences and Municipality Government of Shanghai, is to build a third generation light source of high performance and cost effectiveness, and to provide powerful X-rays for users in China and other parts of the world in various fields of research. The SSRF complex consists of a 150 MeV linac, a 3.5 GeV booster of 180 m in circumference, a 3.5 GeV storage ring of 432 m in circumference (see Table 1), and seven beamlines at phase I stage (see Table 2). The SSRF storage ring is designed to run at a current up to 300 mA and an emittance of 3.9 nm·rad. With advanced insertion devices, it can provide high intensity X-rays of 1020 photons/ (s·mm2·mrad2·0.1%·BW) in maximum brilliance.

Computing tools and analysis architectures: the CMS strategy

The offline and computing activities in preparation to the CMS data taking are reviewed. The readiness of the computing fabric and the status of the Grid services employed by CMS are presented. The strategy towards the full commissioning of the computing and offline systems is discussed.

First cryogenic testing of the ATLAS superconducting prototype magnets

The superconducting magnet system of the ATLAS detector will consist of a central solenoid, two end-cap toroids and the barrel toroid made of eight coils (BT) symmetrically placed around the central axis of the detector. All these magnets will be individually tested in an experimental area prior to their final installation in the underground cavern of the LHC collider. A dedicated cryogenic test facility has been designed and built for this purpose. It mainly consists of a 1200 W at 4.5 K refrigerator, a 10 kW liquid nitrogen pre-cooling unit, a cryostat housing liquid helium centrifugal pumps, a distribution valve box and transfer lines. Prior to the start of the series tests of the BT magnets, two model coils are used at this facility. The first one, the so-called B00 of comparatively small size, contains the three different types of superconductors used for the ATLAS magnets which are wound on a cylindrical mandrel. The second magnet, the B0, is a reduced model of basically identical design concept as the final BT magnets. Full commissioning of all sub-systems including cryogenics, electrical powering, magnet protection and control is done ahead of the arrival of the BT series magnets. This cryogenic test facility reproduces the final thermo-hydraulic conditions in the cooling circuits of the magnets in order to validate the design concept.

An integrated analytical strategy for liquid effluent management

As part of ZENECA's commitment to continually improve the environmental performance of its manufacturing sites, the design and construction of a liquid effluent management facility at Huddersfield Works has provided the hardware and infrastructure to allow a more timely and efficient response to abnormal occurrences resulting from the Works' manufacturing operations. The project comprised the installation of on-line analytical instrumentation designed to both detect and initiate a response to abnormal discharges to effluent drain, together with the construction of several containment tanks, associated ductwork and control mechanisms. Full commissioning of the £4 million facility took place during December 1992. The on-line analysers chosen, based on the determination of total carbon content and UV—visible spectrophotometry, were deemed to be the most appropriate for a manufacturing site handling in excess of 4000 different chemicals. An extensive development phase explored the response of the analysers to ‘typical’ and ‘abnormal’ loadings of selected chemicals and enabled realistic alarm levels to be set. The on-line installations have been complemented by the development of state of the art laboratory-based technologies, designed to characterise or confirm the precise nature of, and therefore the disposal options for, an abnormal discharge following its interception. Such techniques also have use in source attribution and subsequent enhancement of the environmental performance of individual plants and processes.