1. Introduction
The 2016 Amplifier-TCA provides the basic signal processing function for x-ray de-
tectors used in high-rate applications such as EXAFS (Extended X-ray Absorption
Fine Structure). The Amplifier provides gain, filtering, baseline restoration and ICR
pulse discrimination. The TCA provides three computer controlled pulse height (en-
ergy) analyzers with selectable pileup rejector and different pulse output options suit-
able for counting. In addition the 2016 has a built-in multiplexing function which,
under computer control, selects the amplifier output and SCA output from each of up
to thirty-two 2016’s in a system for routing to an MCA (multichannel analyzer) for
window set up. All of this capability is in a single-wide NIM allowing large scale sys-
tems to be built compactly.
Amplifier Function
The 2016 amplifier is based on the Canberra Model 2025-2026 series of amplifiers
which have been used extensively in x-ray and gamma-ray spectroscopy. The shaping
time constants have been selected to enhance the throughput rate. The 2016A offers
higher throughput rate while the 2016B has longer time constants needed for high res-
olution at lower rates and for low energy (<1 keV) applications.
Version
Shaping (
µ
s)
2016A
1/8, 1/4, ½, 1, 2, 3
2016B
1/4, ½, 1, 2, 4, 6
Pulse Height Analyzer Function
The SCA function comprises three independently computer-controlled, single-channel
analyzers each of which provides a logic pulse output for each input pulse falling
within its preset energy window. Window settings are set using computer control over
an Ethernet link to an Acquisition Interface Module (AIM). The AIM to 2016 module
interface is accomplished through Canberra’s Instrument Control Bus (ICB) for com-
plete control of SCA settings and multiplexed output as described below. For conve-
nience, the window is set symmetrically around a centroid voltage (energy) level. The
module’s pileup rejector, when enabled by computer, inhibits SCA outputs resulting
from input signals that are distorted due to pile-up.
