<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2007000900012</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Initial results of the mexican participation in the Alpha Magnetic Spectrometer Project]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Belmont-Moreno]]></surname>
<given-names><![CDATA[E]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Menchaca-Rocha]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sandoval]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Alfaro]]></surname>
<given-names><![CDATA[R]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Martínez-Dávalos]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Grabski]]></surname>
<given-names><![CDATA[V]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Fisica ]]></institution>
<addr-line><![CDATA[México D.F.]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>02</month>
<year>2007</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>02</month>
<year>2007</year>
</pub-date>
<volume>53</volume>
<fpage>49</fpage>
<lpage>51</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2007000900012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2007000900012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2007000900012&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[México is part of the AMS (Alpha Magnetic Spectrometer) project, consisting of several radiation detectors integrated in a single telescope to be sent to the outer space in search of antimatter. One of those detectors is a RICH (Ring Imaging Cherenkov), where the cosmic particle's speed is calculated from the Cherenkov light-rings observed. The IF-UNAM group works in characterizing the silica aerogel used as luminous element in this detector. Because the spectrometer will be in orbit for several years, some particular studies are necessary. Our group works on possible ageing mechanisms, showing that the main threat to this material is contamination rather than thermal, or vacuum, shocks.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[México es parte del proyecto AMS (Alpha Magnetic Spectrometer) que está constituido por varios detectores de radiación integrados en un telescopio que será enviado al espacio exterior en búsqueda de antimateria. Uno de los detectores es de tipo RICH (Ring Imaging Cherenkov), donde se calcula la velocidad de las partículas cósmicas a partir de los anillos de luz Cherenkov. El grupo del IF-UNAM trabaja en la caracterización del aerogel de sílica que se usa como elemento luminoso en este detector. Como el espectrómetro estará en orbita varios años, son necesarios algunos estudios específicos. Nuestro grupo estudia los posibles mecanismos de añejamiento, mostrando que la mayor amenaza a este material es la contaminación más que los choques térmicos, o de vacío.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[AMS]]></kwd>
<kwd lng="en"><![CDATA[RICH]]></kwd>
<kwd lng="en"><![CDATA[aerogel]]></kwd>
<kwd lng="es"><![CDATA[Espectrómetro magnético alfa]]></kwd>
<kwd lng="es"><![CDATA[detector RICH]]></kwd>
<kwd lng="es"><![CDATA[aerogel]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="center"><font face="verdana" size="4"><b>Initial results of the mexican participation in the Alpha Magnetic Spectrometer Project</b></font></p>     <p align="center"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="2"><b>E. Belmont-Moreno, A. Menchaca-Rocha, A. Sandoval, R. Alfaro, A. Mart&iacute;nez-D&aacute;valos, and V. Grabski</b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>Instituto de Fisica, Universidad Nacional Aut&oacute;noma de M&eacute;xico Apartado Postal 20-364, 01000 M&eacute;xico D.F., M&eacute;xico.</i></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">Recibido el 2 de marzo de 2006    <br> Aceptado el 18 de agosto de 2006</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">M&eacute;xico is part of the AMS <i>(Alpha Magnetic Spectrometer) </i>project, consisting of several radiation detectors integrated in a single telescope to be sent to the outer space in search of antimatter. One of those detectors is a RICH (Ring Imaging Cherenkov), where the cosmic particle's speed is calculated from the Cherenkov light-rings observed. The IF-UNAM group works in characterizing the silica aerogel used as luminous element in this detector. Because the spectrometer will be in orbit for several years, some particular studies are necessary. Our group works on possible ageing mechanisms, showing that the main threat to this material is contamination rather than thermal, or vacuum, shocks.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Keywords: </b>AMS; RICH: aerogel.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>     <p align="justify"><font face="verdana" size="2">M&eacute;xico es parte del proyecto AMS <i>(Alpha Magnetic Spectrometer) </i>que est&aacute; constituido por varios detectores de radiaci&oacute;n integrados en un telescopio que ser&aacute; enviado al espacio exterior en b&uacute;squeda de antimateria. Uno de los detectores es de tipo RICH (Ring Imaging Cherenkov), donde se calcula la velocidad de las part&iacute;culas c&oacute;smicas a partir de los anillos de luz Cherenkov. El grupo del IF-UNAM trabaja en la caracterizaci&oacute;n del aerogel de s&iacute;lica que se usa como elemento luminoso en este detector. Como el espectr&oacute;metro estar&aacute; en orbita varios a&ntilde;os, son necesarios algunos estudios espec&iacute;ficos. Nuestro grupo estudia los posibles mecanismos de a&ntilde;ejamiento, mostrando que la mayor amenaza a este material es la contaminaci&oacute;n m&aacute;s que los choques t&eacute;rmicos, o de vac&iacute;o.</font></p>     <p align="justify"><font face="verdana" size="2"><b>Descriptores: </b>Espectr&oacute;metro magn&eacute;tico alfa; detector RICH; aerogel. </font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">PACS:  78.20.Ci</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v53s3/v53s3a12.pdf">DESCARGAR ART&Iacute;CULO EN FORMATO PDF </a></font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>Acknowledgements</b></font></p>     <p align="justify"><font face="verdana" size="2">We wish to thank Hector Cr&uacute;z Manjarrez for his collaboration.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>References</b></font></p>     <!-- ref --><p align="justify"><font face="verdana" size="2">1. S.C.C. Ting, Phys. Rep. <b>279 </b>(1997) 203.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338697&pid=S0035-001X200700090001200001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">2. AMS Collaboration, Phys. Lett B <b>461 </b>(1999) 387.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338698&pid=S0035-001X200700090001200002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">3. AMS Collaboration, Phys. Rep. <b>366 </b>(2002) 331.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338699&pid=S0035-001X200700090001200003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">4. M. Buenerd and T. Thuillier, AMS Internal note. ISN Grenoble 99/122, 8 Nov. 1999.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338700&pid=S0035-001X200700090001200004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">5. M. Villoro et al., Nucl. Inst. Meth. A <b>480 </b>(2002) 456.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338701&pid=S0035-001X200700090001200005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">6. A. Mart&iacute;nez-D&aacute;valos et al. Nucl. Inst. Meth. A <b>553 </b>(2005) 177.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338702&pid=S0035-001X200700090001200006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">7. A.K. Cougas et al. Nucl. Instr. Meth. A <b>421 </b>(1999) 249.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338703&pid=S0035-001X200700090001200007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">8. Mariane Brinet, private communication.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338704&pid=S0035-001X200700090001200008&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p align="justify"><font face="verdana" size="2">9. CIEMAT group, Madrid, private communication.</font>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8338705&pid=S0035-001X200700090001200009&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> ]]></body><back>
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