Ametek ORTEC digiBASE, User Manual

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1. INTRODUCTION
The ORTEC
®
digiBASE
®
is a 14-pin photomultiplier tube base for gamma-ray spectroscopy
applications with NaI(Tl) scintillation detectors, and accommodates virtually all 14-pin tube
bases used with NaI detectors. The digiBASE combines a miniaturized preamplifier and detector
high voltage (0 V to +1200 V bias) with a powerful digital multichannel analyzer and special
features for fine time-resolution measurements, all incorporated into a lightweight (10.1 oz),
compact (63 mm diameter × 87 mm length) tube base with a USB connection. Everything
needed to connect to your NaI(Tl) detector is included in the tube base — no interface card to
install, no external NIM-based components.
NaI(Tl) detectors have a gain that is sensitive to changes in ambient temperature and magnetic
fields. The digiBASE incorporates a gain stabilizer to significantly diminish this sensitivity. It
works by monitoring the centroid of a designated peak in the energy spectrum; the fine gain is
automatically and continuously adjusted to maintain the centroid of the peak at its desired
position.
The digiBASE is supplied with our MAESTRO
®
MCA Emulation Software. For those who wish
to integrate the digiBASE into their own software systems, we offer the C
ONNECTIONS
Program-
mer’s Toolkit (A11-BW). The Toolkit offers Microsoft
®
ActiveX
®
con-trols to simplify pro-
gramming with National Instruments LabVIEW
®
, and Microsoft Visual C++ and Visual Basic.
Installing the digiBASE is a snap with its USB connection. Just install the accompanying
C
ONNECTIONS
Driver Update Kit and MAESTRO software, connect the digiBASE to the USB
port of the computer, start MAESTRO, and begin making measurements — it’s that easy.
MAESTRO contains all the controls needed to adjust the acquisition parameters, acquire the
data, and save the spectra. As a member of our C
ONNECTIONS
family of ORTEC products, it also
provides full networking with other ORTEC MCBs and supporting computers.
If you need the ultimate in fine time resolution — especially important for Homeland Security
applications — the digiBASE features
List Mode operation, in which each valid input signal is
converted to a digital value, which is transmitted to the computer along with the time the event
occurred. Time is measured to the nearest microsecond. Each event causes a 32-bit word to be
transmitted to the computer. (See Appendix A for a detailed discussion of this feature and how
to capture the data stream generated in this mode.)
If you wish to use more than one digiBASE, ORTEC offers four- and seven-port, powered USB
hubs (ORTEC Models C-USB-HUB-4B and C-USB-HUB-7B, respectively) rated for both high-
and low-speed USB operations. Daisy-chain multiple hubs to control as many as 255 units from
a single computer (their use is, however, subject to some limitations, as discussed in Sec-
tion A.2). In addition, we offer a 5-m USB Active Extension Cable (Part No. USBEXT). A max-
imum of five cables can be daisychained per instrument, allowing you to connect your digiBASE
to a computer 25 m away.
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