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 CONNECTIONS 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
CONNECTIONS 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 CONNECTIONS 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.
1
To Next Page
Loading...
