| 1. |
- Szymanski, J. J., et al.
(författare)
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MEGA : A search for the decay mu –> e gamma
- 1994
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Ingår i: Intersections between particle and nuclear physics. Proceedings, 5th Conference, St. Petersburg, USA, May 31-June 6, 1994. ; , s. 789-792
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Konferensbidrag (refereegranskat)
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| 2. |
- Amann, F., et al.
(författare)
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A search for murarregamma at the level of 10-13
- 1991
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Ingår i: Proceedings of the 25th International Conference on High Energy Physics. - 9810024347 ; , s. 1070-1071
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Konferensbidrag (refereegranskat)abstract
- The MEGA experiment, which is a search for the decay murarregamma with a branching ratio sensitivity of about 10-13, employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5-T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the design have been validated in engineering runs; data taking will begin in 1990 with much of the electron arm and one pair spectrometer layer installed.
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| 3. |
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| 4. |
- Stanislaus, S., et al.
(författare)
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Results from beam tests of MEGA's low-mass, high-rate cylindrical MWPCs
- 1992
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 323:1-2, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- One of the leading experimental projects at LAMPF has been the MEGA experiment. This is an experiment to search for the rare decay μ → eγ with a sensitivity of 10-13. A prime component of this project has been the design and construction of high-rate, low-mass MWPCs for the tracking of positrons from muon decay. With rate capabilities of 2 × 104 e+/mm2/s and a thickness of 3 × 10-4 radiation lengths, these chambers are state-of-the-art cylindrical MWPCs. Cylindrical chambers of this size (0.9 m2) and thinness have never been previously constructed. The MEGA project at LAMPF has recently succeeded in building chambers with these necessary performance characteristics as demonstrated by data taken from muon decays, cosmic rays, and sources. © 1992.
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| 5. |
- Mischke, R. E., et al.
(författare)
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Low mass, high rate cylindrical MWPCs for the MEGA experiment
- 1990
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Konferensbidrag (refereegranskat)abstract
- The construction of MWPCs for the MEGA experiment at LAMPF are described. The chambers are cylindrical, low mass (3 {times} 10{sup {minus}4} radiation lengths), and are designed to operate at high rates (3 {times} 10{sup 4} /mm{sup 2}/s). Several novel construction techniques have been developed and custom electronics have been designed to help achieve the required performance, which corresponds to that needed at high luminosity colliders.
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| 6. |
- Stamey, T. A., et al.
(författare)
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Tumor markers. Consensus Conference on Diagnosis and Prognostic Parameters in Localized Prostate Cancer. Stockholm, Sweden, May 12-13, 1993
- 1994
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Ingår i: Scandinavian Journal of Urology and Nephrology, Supplement. - 0300-8886. ; :162, s. 73-87
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Tidskriftsartikel (refereegranskat)abstract
- This chapter mainly deals with biochemical aspects on prostate specific antigen (PSA) and its clinical value. To a limited extent, also other tumor markers, which might be of importance in the evaluation of patients with prostate cancer are discussed. In serum, PSA exists in a free form or bound to antichymotrypsin. Interestingly, only 10% of PSA secreted from cancer cells seems to exist in a free form, as compared to 30% of PSA secreted from cells in benign prostatic hyperplasia (BPH). PSA seems to be closely, but not absolutely, related to tumor grade and stage. The mean value of PSA in patients with tumors dominated by Gleason grades 3 or below, was 10 ng/ml, compared to 29 ng/ml in those with higher grades. Patients with PSA values of 50 ng/ml or above almost exclusively had tumor of Gleason grades 4 or 5, and this limit usually reflected a generalized disease. Patients with PSA-values below 10 ng/ml almost exclusively had tumors confined to the prostate gland. In countries where screening for prostate cancer is believed in, it is important to understand that normal cut-off values are related to patient's age. The upper normal limit of males below 50 years of age should be set at 2.5 ng/ml, as compared to 6.5 ng/ml for men over 70 years of age. To improve the value of PSA determination and for scientific purposes, the standardization of the assay is urgently needed and under way. Prostate acid phosphatase (PAP) has in most centres been replaced by PSA. An elevated PAP value, as measured by the enzymatic method, invariably indicates a generalized disease and could thus be used as a complementary informative assay to PSA. Other markers have been used mainly to achieve additional prognostic information. In a multivariate analysis, the non-specific tumor marker neopterin, which reflects the host response to tumor antigens, was closely related to short-term prognosis. Neopterin was followed by thymidine kinase, a protein reflecting the cell turn-over and tumor grade. Also PSA at diagnosis seemed to add some prognostic information, whereas other markers did not.
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| 7. |
- Armijo, V., et al.
(författare)
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A fast MWPC with cathode strips and utilizing CF4-isobutane
- 1991
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 303:2, s. 298-308
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Tidskriftsartikel (refereegranskat)abstract
- A planar wire chamber has been developed at LAMPF as a prototype for wire chambers of cylindrical configuration for electron detection in the MEGA experiment. Results form tests with the planar chamber have been used to set the geometrical parameters and predict the performance characteristics of the cylindrical chambers. The behavior of the planar chamber with CF4-isobutane gas demonstrates that 15 μm wire of 1 mm pitch is practical, that lifetimes greater than 0.045 C/cm are achievable and that gate widths of 25 ns are possible. © 1991.
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