For the development of charged particle detectors based on straw tubes operating in vacuum, a special measurement technique is required for the evaluation of their mechanical properties. A summary of ...the known equations that govern straw behavior under internal pressure is provided, and a new experimental method of a strained pressurized straw tube study is presented in this paper. The Poisson’s ratio of the straw wall, which defines the stability conditions of a built-in tube, was measured for the NA62 spectrometer straw, and its minimum pre-tension was estimated.
The thin-wall tube drift chamber operating in vacuum (prototype) Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Volume:
718
Journal Article
Peer reviewed
The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology ...were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36μm, diameter 9.80mm, length 2160mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes.
Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.
: To investigate the otolith contribution to the responses of “vestibular only” neurons in the rostral fastigial nucleus (FN), single‐unit activity was recorded in the alert monkey with the head ...fixed during static and dynamic stimulation (± 15 deg, 0.06‐1.4 Hz) around an earth‐fixed horizontal axis. Head orientation could be altered allowing for roll, pitch, and intermediate planes of orientation. For the vast majority of neurons a response vector orientation (RVO) with an optimal response and a null‐response at a head orientation 90 deg apart could be determined. Presumably more than 30% of the vestibular only neurons had an otolith input, as indicated by responses to static tilt, head‐position‐related activity, large phase changes (> 100 deg) of neuronal activity between 0.06 and 1.4 Hz, changes of the RVO at different frequencies and complex responses (spatio‐temporal convergence). Thus, neurons in FN reflecting an otolith or a combined canal‐otolith input are much more common than up to now thought. Vestibular‐only neurons are most likely involved in vestibulospinal mechanisms. Their precise functional role has yet to be determined.
Development of low-mass drift chambers for the HADES spectrometer Bokemeyer, H; Boyard, J.l; Chepurnov, V ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
2002, Volume:
477, Issue:
1
Journal Article, Conference Proceeding
Peer reviewed
The High Acceptance Di-Electron Spectrometer (HADES) is a detector arrangement combined with a superconducting toroid for lepton pair spectroscopy presently built up at GSI (Darmstadt). HADES is ...designed to cope with the high-multiplicity environment of heavy ion collisions at 1
AGeV and intensities of up to 10
8 beam particles per second and central event rates of
10
5
s
−1
. The detector has a geometrical acceptance of almost 50% for e
+e
− pairs and a mass resolution of 0.8% for
ρ and
ω mesons. Four low-mass drift chamber systems, two before and two behind the magnet, serve for charged particle track reconstruction. Design aspects of the drift chambers and first results from beam tests are presented.
Optimisation of low-mass drift chambers for HADES Garabatos, C; Karig, W; Müntz, C ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/1998, Volume:
412, Issue:
1
Journal Article
Peer reviewed
A set of low-mass drift chambers designed for the tracking of di-electrons in the HADES spectrometer is presented. Short radiation length is ensured by using a Helium-based gas mixture and aluminium ...cathode wires, whereas the acceptance is maximised by limiting the width of the side frames of the detectors. The measured performance of these devices, which improves with increasing concentration of quencher gas, is shown and discussed. Position resolutions down to 70
μm have been obtained under stable operation. Long-term gain stability is also reported.
Endometrial carcinoma incidence in Georgia from 1965 to 1992 was 5.3 women per 100,000 and in the structure of gynecological malignant tumors this pathology occupied third place (19.1%). Morbidity ...incidence varied from 2 to 8 depending on ethnic regions overall a 2.5 times rise in morbidity was observed. Within the period of 1968-1994 1731 patients with uterine carcinoma were subjected to surgical intervention (stage I-81.2%; stage II-9.4%; stage III-9.0%; stage IV-0.3%). Surgical intervention is the optimal method to determine the stage of the disease and planning of adjuvant treatment. Metastases in regional lymph nodes were found in 13.0% (T1-7.7%; T2-20.07%; T3-35.3%). Adenocarcinoma was histologically confirmed in 97.4% (G1-21.3%; G2-57.8%; G3-18.8%). Management of the disease was predominantly started with surgical intervention. In pathogenetic version I (71.4%) total extirpation of the uterine was carried out, while in cases of the pathogenetic version II (28.6%) patients were subjected to the modified extended extirpation. Postoperative management was prescribed based on the peculiarities of the organism and tumor. Highly sensitive classification of endometrial carcinoma of stage I (including 5 subgroups) as well as a synoptic table of optimal management were worked out. As a result, 5 year survival increased by 15%, and 29% of the women operated were spared from additional treatment. On the whole, five-year-survival was observed in 71.0% of women (stage I-77.7%; Early Form-95.5%; stage II-51.5%; stage III-34.2%).
For the development of charged particle detectors based on straw tubes operating in vacuum, a special measurement technique is required for the evaluation of their mechanical properties. A summary of ...the known equations that govern straw behavior under internal pressure is provided, and a new experimental method of a strained pressurized straw tube study is presented in this paper. The Poisson's ratio of the straw wall, which defines the stability conditions of a built-in tube, is measured for the NA62 spectrometer straw, and its minimum pre-tension is estimated.
Physiological intracranial calcification occurs in about 0,3-1,5% of cases. It is asymptomatic and is detected incidentally by neuroimaging. Pathological basal ganglia calcification is due to various ...causes, such as: metabolic disorders, infectious and genetic diseases and other. Hypoparathyroidism and pseudohypoparathyroidism are the most common causes of pathological basal ganglia calcification. Besides tetany and seizures this condition is presented by parkinsonism and dementia. Such parkinsonism doesn't respond to drugs containing levodopha. Infections (toxoplasmosis, rubella, cytomegalovirus, cysticercosis, AIDS) give multiple and asymmetric intracranial calcification. Inherited and neurodegenerative diseases cause symmetrical, bilateral basal ganglia calcification which is not related to metabolic disorders (blood calcium level and other), those are: Cockayne syndrome, tuberous sclerosis, Fahr's syndrome, Down syndrome and other. We observed some cases of basal ganglia calcification and studied clinical manifestations and treatment tolerance of this pathological condition. Since adequate treatment of hypoparathyroidism may lead to marked clinical improvement, serum concentration of calcium, phosphorus, and parathyreoid hormone is suggested to be determined in all individuals with calcification of the basal ganglia to rule out hypoparathyroidism. Basal ganglia calcification in young patient with acute hepatitis may be result of Wilson disease.
The HADES tracking system Müntz, C.; Markert, J.; Agakichiev, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
535, Issue:
1
Journal Article
Peer reviewed
Open access
The HADES dielectron spectrometer has recently launched its physics program at the heavy ion synchrotron SIS at GSI Darmstadt. The spectroscopy of vector mesons in heavy ion collisions via their ...dielectron decay channel makes great demands on the HADES tracking system regarding acceptance and spatial resolution. The tracking system is formed out of 24 low-mass, trapezoidal multi-layer drift chambers providing about
30
m
2
of active area. Low multiple scattering in the in total four planes of drift chambers before and after the magnetic field is ensured by using helium-based gas mixtures and aluminum cathode and field wires. First in-beam performance results are contrasted with expectations from simulations. Emphasis is placed on the energy loss information, exploring its relevance regarding track recognition.
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