Construction of a new primary beam line, called the B-line, started in 2013 at the J-PARC Hadron Experimental Facility. The B-line is branched at the middle of an existing primary proton beam line ...(A-line) in the beam switching yard (SY), which is the connecting tunnel between the Main Ring (MR) and the Hadron experimental hall (HD-hall). At the branching point, about 0.1% of the primary beam is kicked off at 5 degrees using a Lanbertson magnet and two septum magnets. The Lambertson magnet has a field free hole in its yoke. The proton beam that goes through a field region is separated from the A-line, and it is extracted to the B-line. The rest of the beam that goes through the field free hole is transported through the existing primary beam line. Since a significant beam loss as much as 420 W occurs at the edge of field free hole, the magnets near the Lambertson magnet are operated under a very high radioactive environment. We have developed a "mini-chimney system" regarding easy maintenance of those magnets. The mini-chimney means a vertical tower of approximately 1m in height. The tower is comprised of water pipes, power electrodes, and signal cables for safety interlock. Those can be easily connected and disconnected at the top of chimney on the ceiling iron shields. In this paper we summarize the maintenance scheme developed for the B-line, as well as the design of B-line.In May 2020, the first proton beam was successfully extracted to the B-line by means of the Lambertson and the septum magnets. Up to now, the 10 10 protons per 5.2 sec accelerator cycle shot have been available.
The introduction of Cone Beam Computed Tomography (CBCT) into the alveolar bone grafting protocol now allows surgeons to look at pre- and postoperative bony structures to determine surgical success. ...Until recently, pre- and postoperative assessment have been determined by 2-dimensional (2D) periapical and panoramic radiographs. CBCTs can now be used to volumetrically assess defects. Yet to date, no scale has been standardized to classify alveolar bone grafting levels postoperatively to determine the success of the procedure. This study aims to analyze pre- and postoperative cone bean CBCT scans to determine if variables such as cleft size, canine position, and bone grafting material can help predict surgical outcomes. A total of 79 patients (average 10.4 years) with non-syndromic complete unilateral cleft lip and palate had been treated with ABG and bone morphogenetic protein-2 with demineralized bone matrix (BMP2/DBM) versus iliac crest bone (ICB) were compared. Preoperative CBCT scans (n = 27) were available to determine the cleft width. The postoperative CBCT was analyzed by the Bergland scale score. A novel method for categorizing canine eruption separated post-graft patients into 5 groups. The cleft width might be correlated with bone graft outcomes, but limited to the sample size, with no statistical significance (n = 27, R2 = 0.378, P > .05). In total, 21 (26.6%) patients have supernumerary or impacted teeth in the cleft, but not related to bone graft outcomes. There is no statistical difference between the 4 surgeons’ cleft repair. The 2D modalities traditionally used to interpret SABG results possess inherent limitations of structure overlapping and distortion of the relationship of anatomy. Since the advent of the CBCT, 3D volumetric analysis has largely accounted for these errors. Yet to date, no scale standardized to the CBCT has been developed to assess SABG results.
The authors' results suggest that graft outcomes correlate with pre-graft canine positions. An unerupted, high permanent canine vertical position will yield poor results, likely due to previously documented growth-inhibiting scarring of soft tissue, and the ideal timing of SABG may be when two-thirds of the canine crown is located below the palatal plane with the adjacent premolars not fully erupted. This may be due to the optimal timing for the canine to complete its eruption into the grafting site to influence the maintenance of the graft and periodontal support of the adjacent teeth. In a patient with complete unilateral cleft lip and palate, iliac crest bone graft tended to have better graft outcomes than BMP2/DBM in this sample. This may be attributed to BMP2/DBM's osteoconductive properties vs. ICB's osteogenic, osteoinductive, and osteoconductive properties. There was no evidence that cleft width correlates with the grafting outcome. However, results were limited to sample size.
After the radioactive material leak accident at the J-PARC hadron experimental facility on May 23, 2013, we designed a new production target, which is capable of a primary proton beam with the energy ...of 30 GeV and power of 50 kW. It is made of gold and cooled by water through a copper block. For the countermeasures of the recurrence of the accident, the target is enclosed by an airtight chamber and helium gas is circulated to monitor the target soundness. In this paper, technical details of the new target design are presented.
Patients with craniofacial syndromes that affect mandibular conformation and growth may face significant airway difficulties. Mandibular distraction osteogenesis is a favored surgical approach for ...addressing micrognathia or retrognathia, in which bone is generated at distracted osteotomized segments in order to advance the mandible and improve airway patency1. Patients with severe craniofacial anomalies, including Goldenhar Syndrome, may have unfavorable mandibular anatomy for distraction, and it has been shown that patients with Goldenhar Syndrome have lower success rates with mandibular distraction and more often require tracheostomy2. Novel approaches must be explored to better treat the respiratory issues these patients endure as a result of their craniofacial abnormalities. One infant with a severe form of hemifacial microsomia and airway obstruction requiring oxygen via nasal cannula underwent a novel technique of bilateral extraoral vertical ramus osteotomies with bone graft placement to advance the mandible. Patient outcomes were assessed clinically and with pre- and post-operative computed tomography (CT) scans and polysomnograms (PSG). In November of 2020, one 2-month-old male with hemifacial microsomia and respiratory difficulties underwent bilateral extraoral vertical ramus osteotomies with bone graft placement, as his anatomy made him a poor candidate for mandibular distraction. Post-operative CT scan showed a more anatomical condylar position relative to the glenoid fossa bilaterally, improved chin point position to midline, a more favorable maxillomandibular position, and improved airway patency. Pre-operative PSG showed an apnea-hypopnea index (AHI) of 29.3, with the 1-month post-operative PSG showing an AHI of 17.3 and the 4-month post-operative PSG showing an AHI of 0.6. In neonatal or infant patients with severe forms of craniofacial anomalies, including Goldenhar syndrome, mandibular advancement via bilateral vertical ramus osteotomies with bone grafting is a functional alternative to mandibular distraction osteogenesis. For patients with more severe forms of hemifacial microsomia, including Goldenhar Syndrome, mandibular distraction osteogenesis may not be a predictable approach for relieving airway distress. This case report presents a novel technique for addressing the respiratory difficulties associated with this congenital condition. Bilateral vertical ramus osteotomies with bone graft placement can effectively advance the mandible, stabilizing the airway and avoiding the need for tracheostomy in this population.
This paper reports developments of indirectly cooled radiation-resistant magnet coils, which can be loaded with 2000-A dc. This current capacity is required for the most upstream magnets of a new ...high-momentum beam line to be constructed in the future extension of the J-PARC hadron experimental facility. Indirectly cooled coils using solid-conductor-type mineral insulation cables (MICs) and stainless-steel water pipes were adopted to achieve high radiation hardness. MICs were sandwiched by independent cooling water pipes and stacked in a casing, and the entire coil assembly was filled with solder. However, the maximum load applied to the indirectly cooled MIC coils was limited to 1000-A dc, mainly owing to a heat problem at the end parts of the coils. In pursuit of the required current capability, we have carried out load tests using a test sample of the end parts, which consists of MIC current leads and a copper bus bar connecting the MIC conductors, instead of a whole MIC coil. By improving the structure of the end parts, we have succeeded to operate the test piece stably with 2000-A dc in a vacuum.
Mandibular distraction osteogenesis (MDO) is a favored surgical technique for addressing the airway difficulties that result in patients with Pierre Robin sequence. Devices are placed to distract the ...micrognathic mandible forward and generate bone at bilateral mandibular osteotomies.1 Though it is generally accepted that these patients will continue to develop with disproportionate maxillomandibular growth after distraction2, the timeline for relapse back to a skeletal class II relationship, as well as differences between male and female development post-distraction, is not well-described.
The purpose of this study is to characterize a timeline of maxillomandibular growth for patients with isolated Pierre Robin sequence (iPRS) after MDO during infancy based on Steiner's analysis and clinical impressions, as well as to identify differences in post-distraction growth between males and females. The researchers hypothesized that these patients would demonstrate disproportionate growth after distraction and that females would relapse at a faster rate than males. By improved understanding of this timeline, clinicians may better educate parents with expectations for their child's craniofacial development after distraction.
Department records were retrospectively reviewed to identify patients with iPRS who underwent MDO during infancy from 2004 through 2016. Patients with post-distraction imaging from which cephalometric data could be traced (i.e., lateral cephalograms or cone beam computerized tomography CBCT scans) were included. These were traced by 2 independent reviewers for SNA, SNB, and ANB angles, according to Steiner's analysis to determine skeletal classification. Patients with pre- and post-distraction lateral profile photos were assessed by 1 reviewer for skeletal classification based on clinical appearance. Patient age at distraction, sex, time from initial distraction to imaging study, and prior maxillomandibular surgeries were abstracted. Descriptive statistics and significance testing were performed; 38 patients with iPRS who underwent MDO were identified. Of these, 15 (39.5%) had at least 1 postoperative lateral cephalogram. Average time from surgery to initial lateral cephalogram (TAS) was 67.81 months for all patients (range 25.53 to 129.93 months). The majority of patients (n = 12) had an ANB > 2° at the time of lateral cephalogram. One patient (TAS 25.53 months) had an ANB of 1.3°, whereas 2 patients (both with prior cleft palate repair) had an ANB < 0° (TAS 32.67 and 97.17 months). Nine (60%) of all patients with lateral cephalogram data fell within 1 standard deviation of average TAS (39.52 to 96.1 months), with corresponding average SNA, SNB, and ANB angles of 80.97, 73.99, and 7.03, respectively; 33% of these patients (n = 3) had prior palatal surgery. Of the 38 patients, 37 had pre- and post-distraction lateral photographs; 13 of 15 (86.7%) females, and 12 of 22 (54.5%) males relapsed to a skeletal class II relationship by the last follow-up appointment (P = .04). The mean postoperative follow-up months for females (69.3 months) and males (79.9 months) was similar (P = .50). Based on post-distraction cephalometric tracing, 80% of patients reverted back to a skeletal class II relationship by an average of 68 months. Based on post-distraction clinical appearance, 68% of patients reverted to a class II relationship by an average of 76 months. Furthermore, a more significant percentage of females relapsed to a skeletal class II relationship compared to males at similar follow-up points. These findings may help clinicians and parents better understand and prepare for the maxillomandibular developmental timeline of these patients post-distraction.
Mandibular distraction osteogenesis (MDO) is a favored surgical technique for addressing the airway difficulties that result in patients with Pierre Robin sequence. Devices are placed to distract the ...micrognathic mandible forward and generate bone at bilateral mandibular osteotomies.1 Though it is generally accepted that these patients will continue to develop with disproportionate maxillomandibular growth after distraction2, the timeline for relapse back to a skeletal class II relationship, as well as differences between male and female development post-distraction, is not well-described.
The purpose of this study is to characterize a timeline of maxillomandibular growth for patients with isolated Pierre Robin sequence (iPRS) after MDO during infancy based on Steiner's analysis and clinical impressions, as well as to identify differences in post-distraction growth between males and females. The researchers hypothesized that these patients would demonstrate disproportionate growth after distraction and that females would relapse at a faster rate than males. By improved understanding of this timeline, clinicians may better educate parents with expectations for their child's craniofacial development after distraction.
Department records were retrospectively reviewed to identify patients with iPRS who underwent MDO during infancy from 2004 through 2016. Patients with post-distraction imaging from which cephalometric data could be traced (i.e., lateral cephalograms or cone beam computerized tomography CBCT scans) were included. These were traced by 2 independent reviewers for SNA, SNB, and ANB angles, according to Steiner's analysis to determine skeletal classification. Patients with pre- and post-distraction lateral profile photos were assessed by 1 reviewer for skeletal classification based on clinical appearance. Patient age at distraction, sex, time from initial distraction to imaging study, and prior maxillomandibular surgeries were abstracted. Descriptive statistics and significance testing were performed; 38 patients with iPRS who underwent MDO were identified. Of these, 15 (39.5%) had at least 1 postoperative lateral cephalogram. Average time from surgery to initial lateral cephalogram (TAS) was 67.81 months for all patients (range 25.53 to 129.93 months). The majority of patients (n = 12) had an ANB > 2° at the time of lateral cephalogram. One patient (TAS 25.53 months) had an ANB of 1.3°, whereas 2 patients (both with prior cleft palate repair) had an ANB < 0° (TAS 32.67 and 97.17 months). Nine (60%) of all patients with lateral cephalogram data fell within 1 standard deviation of average TAS (39.52 to 96.1 months), with corresponding average SNA, SNB, and ANB angles of 80.97, 73.99, and 7.03, respectively; 33% of these patients (n = 3) had prior palatal surgery. Of the 38 patients, 37 had pre- and post-distraction lateral photographs; 13 of 15 (86.7%) females, and 12 of 22 (54.5%) males relapsed to a skeletal class II relationship by the last follow-up appointment (P = .04). The mean postoperative follow-up months for females (69.3 months) and males (79.9 months) was similar (P = .50). Based on post-distraction cephalometric tracing, 80% of patients reverted back to a skeletal class II relationship by an average of 68 months. Based on post-distraction clinical appearance, 68% of patients reverted to a class II relationship by an average of 76 months. Furthermore, a more significant percentage of females relapsed to a skeletal class II relationship compared to males at similar follow-up points. These findings may help clinicians and parents better understand and prepare for the maxillomandibular developmental timeline of these patients post-distraction.
The new facility J-PARC has been constructed in Tokai, Japan. It aims at providing intense proton beams of 750 kW for next-generation particle and nuclear physics experiments. The Hadron Experimental ...Hall (HD-hall) is one of the two facilities at the J-PARC Main Ring and utilizes various secondary particles produced by the slowly extracted primary proton beam. We have constructed two charged and one neutral secondary beam lines. The K1.8 beam line transports separated charged secondaries with the maximum momentum of 2 GeV/c. Secondary particles are purified by two electrostatic separators (ESSs). The K1.8BR beam line is branched from the K1.8 at the bending magnet downstream of the first ESS. The K1.8BR delivers separated charged beams with the momentum up to 1.2 GeV/c. On January 27th, 2009, the first beam was successfully extracted to the HD-hall and transported to the beam dump. The first secondary beam extraction to the K1.8BR beam line succeeded in February 2009. The beam commissioning of the K1.8 and KL beam lines started in October 2009.
The target station in the hadron experimental facility at J-PARC consists of a production target and a huge vacuum chamber in which several secondary-beam-line magnets can work. This vacuum chamber ...system aims to remove the vacuum beam pipe from the magnet gap, because the cooling of the beam pipe is the most serious problem in the high intensity beam facility. We have developed indirectly cooled radiation-resistant magnets for the hadron target station. Their coils are made of solid-conductor type mineral-insulation cables and stainless-steel water pipes. They have the great advantages that electric circuits can be completely independent of water pass. The mechanical strength and the insulation performance of the coil are significantly improved also because the insulation water pipes can be avoided from the water pass. A C-type sector dipole and a figure-8-type quadrupole magnet have been fabricated by using indirectly cooled radiation-resistant magnet technology, and installed in the vacuum chamber. We have succeeded to operate them in vacuum stably with the current of DC 1000 A by improving the end structure of the MIC coils and increasing their emissivity. These magnets have been used for the real beam operation without any serious problems.
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