HotSpotter? Neutron/Gamma Detector Page: 6 of 10
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
DIGITAL ELECTRONICS
The integrated components in the digital circuit are low power surface mount parts operating at
5.0V logic levels. A block diagram of the main components of the digital subsection is shown in
Figure 1, below.
LCD Switches
ADC -Microprocessor - Data Memory
Transceiver
Figure 1, Digital Electronics Block Diagram
The device is controlled by a 12 MHz Philips Semiconductor P89C51RD+ microprocessor having
64K bytes of code memory and 1K byte of random-access memory (RAM). An additional 32K
bytes of static RAM is provided by a Cypress CY62256 static RAM interfaced to the
microprocessor through a 74VHC373 octal D latch. A Xicor X25642 non-volatile 8K byte RAM is
interfaced to the microprocessor by a serial peripheral interface (SPI). A Maxim MAX814K
microprocessor supervisory circuit controls the microprocessor's power-on reset and low-power
reset.
The analog-to-digital converter is a Maxim MAX1242 10-bit ADC interfaced to the microprocessor
through a serial peripheral interface (SPI). A Xicor X9410 quad digitally controlled potentiometer
is interfaced to the microprocessor through the SPI. Two of the 10 kQ potentiometers control the
gain and offset stages mentioned previously; the other two are unused. A Maxim MAX3223 RS-
232 transceiver was included for uploading spectra, testing and diagnostics purposes.
An Optrex DMC16207 LCD, configured as 16 characters by 2 lines, is interfaced to the
microprocessor for displaying operator text information. The microprocessor is also interfaced to
two push buttons that are used for operator input. A power on/off switch is provided external to the
device enclosure.
The analog and digital circuits share the printed circuit board. Positive voltage for both the analog
and digital sides is provided by two Maxim MAX883 +5V regulators; negative voltage for the
analog side is provided by two Maxim MAX664 -5V regulators. High-voltage for the
photomultiplier is generated by a Hamamatsu model C4900-01 high voltage converter supplied by
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Bell, Z. W. HotSpotter? Neutron/Gamma Detector, report, April 1, 2003; Oak Ridge, Tennessee. (https://digital.library.unt.edu/ark:/67531/metadc734451/m1/6/: accessed March 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.