A dedicated X-ray tomograph has been developed at CERN to control the required wire placement accuracy of better than 20
μm of the 1200 Monitored Drift Tube Chambers which make up most of the ...precision chamber part of the ATLAS Muon Spectrometer. The tomograph allows the chamber wire positions to be measured with a 2
μm statistical and 2
μm systematic uncertainty over the full chamber cross-section of 2.2×0.6
m
2. Consistent chamber production quality over the 4-year construction phase is ensured with a ∼15% sampling rate. Measurements of about 70 of the 650 MDT chambers so far produced have been essential in assessing the validity and consistency of the various construction procedures.
The muon spectrometer of the ATLAS detector for the Large Hadron Collider is designed to provide a muon transverse momentum resolution of 2%–10% for momenta between 6
GeV and 1
TeV over a ...pseudo-rapidity range of |
η|⩽2.7. This required the development of precision drift chambers with a track position resolution of
40
μ
m, the Monitored Drift Tube (MDT) chambers. We report about the construction of the three main types of MDT chambers for ATLAS, test results and the first production experience.
The LHC under commissioning at CERN will be the world's largest superconducting accelerator and therefore makes extensive use of cryogenic instruments. These instruments are installed in the tunnel ...and therefore have to withstand the LHC environment that imposes radiation-tolerant design and construction. Most of the instruments require individual calibration; some of them exhibit several variants as concerns measuring span; all relevant data are therefore stored in an Oracle(R) database. Those data are used for the various quality assurance procedures defined for installation and commissioning, as well as for generating tables used by the control system to configure automatically the input/output channels. This paper describes the commissioning of the sensors and the corresponding electronics, the first measurement results during the cool-down of one machine sector; it discusses the different encountered problems and their corresponding solutions.
A low-cost and reliable system is presented which was developed for the gas leak rate measurement of the BIS-Monitored Drift Tubes (MDT) to be used for the Muon Spectrometer of the ATLAS experiment ...at LHC. In order to meet the ATLAS schedule, 100
MDTs are tested simultaneously each time by the developed setup. The method used is based on the measurement of the gas pressure drop in each MDT with respect to the pressure of a gas tight reference tube within a time interval of 48
h and is accomplished with a differential manometer. A high degree of temperature stability and homogeneity is achieved inside two thermally insulated boxes and leads to a satisfactory accuracy for the measurement of the gas leak rates. The developed system is appropriate within the ATLAS specifications for mass production. More than 18500
MDTs have been tested up to now and the obtained results are presented.
Background:
MPAL is a heterogeneous category in the World Health Organization (WHO) that comprises acute leukemias with discrete admixed populations of myeloid and lymphoid blasts (“bilineal”) or ...with extensive coexpression of lymphoid and myeloid markers in a single blast population (“biphenotypic”). Mixed phenotype acute leukemia (MPAL) accounts for 2–5% of newly diagnosed acute leukemia. WHO criteria highlight key lineage‐defining markers with particular emphasis on CD19 for B lineage, CD3 for T lineage, and myeloperoxidase (MPO) for myeloid lineage.
Aims:
Review of classification, biology, clinical features, and treatment approach to MPAL.
Methods:
We studied retrospectively 1163 consecutive patients diagnosed with acute leukemia at the G. Papanicolaou Hospital, Thessaloniki, Greece, from 1999 until January 2019 subclassified as follows: AML = 854, B‐ALL = 172, T‐ALL = 80, acute undifferentiated leukemia = 9, MPAL/BAL = 44, diagnosed using either the WHO (13/44) or the EGIL (31/44) criteria.
Results:
Of the 31 patients diagnosed with biphenotypic acute leukemia (BAL) using the EGIL classification 12 did not fulfill the WHO criteria for MPAL. Only 2 B‐Myeloid cases according to the WHO classification did not fulfill EGIL criteria. We reclassified all cases following the WHO criteria and resulted in 32 MPAL cases (2.8% of the cohort; 24/32 B‐Myeloid, 7/32 T‐Myeloid, 1/32 B‐T‐MPAL).
Aberrant T‐cell marker expression was seen in 6 patients with B‐Myeloid MPAL, CD7 expression being the most frequent. In T‐Myeloid MPAL, the cytoplasmic CD79a B‐cell marker was aberrantly expressed in 4/7 cases (57%). HLA‐DR was expressed in all MPAL cases. TdT was positive in all Ph+ MPAL, compared to 26% in non‐Ph+ MPAL cases. Seventy‐three percent of the cases were classified as ALL by morphology. Clinical data was available in 25/32 patients; 18 males, 7 females, median age: 32 years (2–79). Median WBC count at presentation was 10.6 × 109/L, hemoglobin 9.3 g/dL, platelets 63 × 109/L, LDH 839 IU/L and marrow blast count 55%. Cytogenetic data available for 29/32 patients were as follows; normal karyotype = 5 (17.2%), t(9;22) translocation = 7 (24.1%), complex karyotype (CK) = 14(48.2%), monosomy 7 = 5 cases (17.2%).
Response to treatment and outcome were available for 24 and 29 patients, respectively; 18 received ALL‐type therapy, 3 received AML‐type therapy, 2 a combination of ALL+AML therapy. All Ph+ patients received Tyrosine Kinase Inhibitor (TKI). One died before receiving treatment. ALL‐type treatment induced a response in 13/18 patients (72%), whereas AML‐type in 33.3%; both patients who received combination therapy responded. All refractory patients (7/24) had a complex karyotype. Fourteen patients underwent allogeneic hematopoietic cell transplantation (allo‐HCT). Median overall survival (OS) was 18.7 months; 12 and 27 months for patients with CK and t(9;22) respectively, while the 5‐year survival rate was 12.5%. In contrast, BAL patients classified according to EGIL had median OS 23.3 months.
Summary/Conclusion:
In our study, reclassification of BAL (EGIL) patients as per WHO, resulted in a more accurate characterization of acute leukemias with mixed phenotypic features. Our study confirms that MPAL/BAL displays a uniformly poor outcome especially in patients with CK. The addition of TKI in the treatment of Ph+ patients probably ameliorates MPAL poor prognosis. Upon validation in larger prospective cohorts, MPAL could be considered as an independent poor risk feature for leukemia patients.
We have measured the response of an array of ATLAS muon spectrometer drift tubes to fast neutrons, produced by a t(d,n)/sup 4/He reaction at the 5.5-MV TANDEM Van de Graaff accelerator of the ...National Centre of Scientific Research "Demokritos." The setup consisted of 24 drift tubes in a 6/spl times/4 arrangement. The neutron energy was 18.3 MeV. The anode wire voltage varied from 2200 to 2800 V. For a neutron flux of about 2.75 kHz/cm/sup 2/, the drift tube sensitivity to 18.3-MeV neutrons ranged from 0.031% to 0.606% for anode voltages between 2200 and 2800 V, respectively.
The ATLAS detector at the Large Hadron Collider at CERN is designed to study the products of proton collisions at energies up to 14 TeV. One of its subdetectors is a high-resolution Muon ...Spectrometer, designed to exploit the physics potential of the collisions. It consists of 1206 monitored drift tube chambers, which have to pass very strict quality criteria. For this purpose dedicated setups have been developed and automated at the National Technical University of Athens. In the present report the results of testing about 10,000 drift tubes are presented. These criteria comprise the anode wire mechanical tension, the high voltage dark current, the anode wire displacement, and the gas leak rate of the endplugs and the cylindrical drift tube.
The accuracy of the ATLAS muon X-ray tomograph Avramidou, R; Berbiers, J; Boudineau, C ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2003, 2003-1-00, Letnik:
496, Številka:
1
Journal Article
Recenzirano
A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, ...designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2
μm systematic and 2
μm statistical uncertainties in the horizontal and vertical directions in the working area 220
cm (horizontal)×60
cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented.
ATLAS (a toroidal LHC apparatus) is a general purpose experiment that will start its operation at the large hadron collider (LHC) at CERN in 2007. The ATLAS detector is designed to explore numerous ...physics processes by recording, measuring, and investigating the products emerging from proton-proton collisions at energies up to 14 TeV. High-precision muon momentum measurement (dp/p/spl sim/10% at p/sub T/=1 TeV/c) over large areas using monitored drift tube (MDT) chambers is crucial for the ATLAS experiment. More than 1200 MDT chambers, consisting of approximately 370 000 drift tubes, will provide a total coverage of 5500 m/sup 2/. Three Greek universities have taken the responsibility to construct 130 barrel inner small (BIS)-MDT chambers using 30 000 drift tubes of /spl sim/1.7 m length that have been quality tested before assembly. The design of the muon drift tubes aims at high detection efficiency (>95%) and a spatial single tube resolution of <80 /spl mu/m. This paper describes the cosmic ray test setup, which has been instrumented in order to verify that the BIS-MDT chamber Module-0 fulfills its design requirements. The analysis of its data shows that the chamber meets these requirements; it has low noise levels, uniform drift properties, good spatial resolution, and high particle detection efficiency.
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