ACP1201

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" height=90 BGCOLOR="#006699" TEXT="#080000" background="1fcfd5a3.jpg"> <div> <FONT SIZE="5" COLOR="#000000" FACE="Arial" ><B>BIT Company</B></FONT><B>    </B><B> |     </B><A HREF="id83.htm" TARGET="_top" TITLE="Nuclear/Photometric Instruments"><U><B>Index</B></U></A></div> <div> </div> </td> </tr><tr> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <B>ACP1201</B></div> <div> <B>Automatic PMT Calibration System</B></div> <bR> <div> <B><IMG SRC="29f90860.jpg" border=0 width="400" height="390" ALIGN="BOTTOM" HSPACE="0" VSPACE="0">             <IMG SRC="2ea4ce90.jpg" border=0 width="332" height="233" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B>Photomultipliers are extremely versitile photosensitive devices used to measure radiant energy from near IR to the ultraviolet regions of the electromagnetic spectrum. Their usage includes scintillation and Cerenkov detectors for nuclear and space instrumentation, laser ranging,and chemical and astronomical spectrum analysers.</B></div> <bR> <div> <B>A critical factor in using PMTs in analytical equipment is maintaining gain stability over time and temperature. The gain is very sensitive to changes in the operating voltage. For example, a common PMT, the 1P28, will change gain approximately 10% for a 1% shift at a normal operating potential of 1,000 volts.</B></div> <bR> <div> <B>DESCRIPTION</B></div> <bR> <div> <B>A very precise pulse of light controlled by closed loop sampling circuitry is applied via a fiber light guide to the PMT to be calibrated. The signal from either the anode or final dynode (dependent on user requirements) is processed to remove all signals but the calibration light pulse. This is compared against a precision reference and controls the PMT potential by floating the cathode. The final step is the subtraction of the calibration pulse before the desired PMT signal appears on the output port.</B></div> <bR> <div> <B>OPTIONS</B></div> <bR> <div> <B>01     Anode charge preamp</B></div> <div> <B>02     Dynode charge preamp</B></div> <div> <B>03     Integral anode supply</B></div> <div> <B>04     Selected light pulse wavelength</B></div> <div> <B>          a) 480 nm          e) 830 nm                                                                                             </B></div> <div> <B>          b) 560 nm          f) 880 nm                                                                                             </B><B> </B></div> <div> <B>          c) 590 nm          g) 900 nm                                                                                             </B></div> <div> <B>          d) 670 nm          h) 950 nm                                                                                             </B></div> <div> <B>06     PMT control on anode                                                                                              </B></div> <div> <B>        </B></div> <div> <A HREF="id17.htm" TARGET="_top" TITLE="Contact Us"><U><B>Contact us</B></U></A></div> <bR> <div> <B>Back to </B><FONT SIZE="3" COLOR="#0000FF" FACE="Arial" ><A HREF="id83.htm" TARGET="_top" TITLE="Nuclear/Photometric Instruments"><U><B>index</B></U></A></FONT></div> </td> </tr></table></body>