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2301 qVt CAMAC INTERFACE
- The Model 3001 is a research grade multichannel analyzer which
provides exceptional versatility at relatively low cost.
- 3-Mode Analysis - Charge (Q, area) and voltage (V, peak) analog-to-digital
conversion and time-to-digital conversion (T, start/stop) modes mean direct
compatibility with photomultiplier anodes and elimination of charge-sensitive
preamps and time-to-amplitude converters (TACs).
- High Sensitivity - Q = 0.25 pC sensitivity in charge mode, V
= 1 mV resolution in peak mode (0 to 1 to 10 volt inputs), and T = 100 psec
resolution in time mode means direct compatibility with low-level signals
from a variety of sources and the ability to precisely measure short time
- Segmentable Memory - 4 x 256 (quadrants) or 1 x 1024 (full scale)
gives the flexibility to accumulate, display, and compare up to four different
spectra or to display quadrants of a full 1024-channel spectrum.
- High Count Capacity - 216 -1 (65,535) counts capacity permits
enough data accumulation to satisfy applica tions including cosmic ray and
high energy experiments and many nuclear spectroscopy and Mossbauer applications.
- Nanosecond Logic Functions - Internal triggering mode permits
the 3001 to be used as a stand-alone device, while the external modes permit
either internal gate generation upon application of an external trigger,
or direct application of an external gate signal.
- Computer I/O - Interfaces through accessory modules, Model 2301,
to the CAMAC Dataway (IEEE-583) or the model 3031 for computer-based data
- Compact Packaging - Complete 1024-channel analyzer, compactly
packaged in a #2 NIM-standard module, gives greater portability, lower cost,
and enhanced reliability.
- Drives Any X-Y Scope - Logarithmic or Linear display. The use
of the 3001 with any external X-Y scope in your lab means smaller basic
analyzer size, greater mobility, and saves you the expense of a built-in
scope which may already be available.
The Model 3001 NIM MCA is a versatile, low cost, 1024-channel multichannel
analyzer offering three analysis modes: charge (area), voltage (peak), and
time (start/stop). Each of the 3001s 1024 channels has a count capac ity
of 16 bits (65,535). The contents may be displayed in log/linear fashion
on any X-Y oscilloscope. The display is active on a time-available basis,
thus affording display during data accumulation. A front-panel switch selects
intensification of every tenth or fiftieth channel. Data may be accumulated
and displayed in selected 256-channel quadrants or in the full 1024-channel
memory. In addition to both an internal and external trigger capability
with variable gate width, the 3001 provides external gate and inhibit inputs,
which are also used as start and stop inputs in the time mode.
Rear-panel digital outputs are supplied to allow for data transfer to interface
options including the CAMAC Dataway (IEEE-583). The output connector may
also be used to load or increment any one of the 16-bit word in memory.
This feature allows the 3001 to be used as an additional 1024 words of memory
and to act as a histo gram display module.
The 10-bit ADC used for the Q (charge) mode has a sensitivity of 0.25 pC/channel,
directly compatible with photomultiplier anodes pulses, thus eliminating
the need for a charge-sensitive preamplifier. In the Q mode, the input current
is integrated for a duration ranging from 20 nsec to 1 µsec. A front-panel
adjustable internal gate is generated by either an internal or an external
trigger, or an external gate pulse may be directly applied to the MCA. Operating
in the Internal mode, the Model 3001 is a stand-alone device, possessing
an internal discrimina tor of 1 mV minimum threshold. The Q input is terminated
in 50 ohm and all analog circuitry is DC-coupled, thus eliminating the need
for DC restoration instrumentation.
The 10-bit TDC used for the T (time) mode of the Model 3001 digitizes time
intervals by the start-stop technique and stores their spectra. Full-scale
time intervals are 102 nsec and 1024 nsec, offering respective resolutions
of 100 psec/channel and 1 nsec/channel. The start and stop inputs are leading
edge triggered, responding to fast NIM (negative) signals. Uses of the T
mode include time-of-flight, counter timing, delay measurement, b-V time
correlation spectra, and drift chamber calibration.
In the V (voltage) mode, the output of any voltage source, e.g., a charge-sensitive
preamplifier, may be analyzed. The maximum (peak) voltage (of signals >
50 nsec rise time) applied to the input during the gating interval is digitized,
thus making external stretching circuits unnecessary. The full-scale input
in the V mode is +1 V (+10 V is switch selectable), offering a resolution
of 1 mV (10 mV) consistent with that of a Si(Li) detector. The internal
gate may be extended to 5 µsec in this mode.
The CAMAC Model 2301 qVt Interface has been designed to allow spectrum
transfer to computer or to allow data transfer to the Model 3001 Multichannel
Analyzer for display or histogramming. The 2301 allows the qVt to
be used for calibration and setup as well as for display during the operation
of an experiment.
The 3001 can be connected directly to an IBM compatible computer by using
the model 3031 QVT interface and Model 1691B interface card. These units
are described on separate data sheets.
The 3001 may be used to set gain and timing of hodoscope or calorimeter
elements. When the first order high voltage and cable delay parameters are
set, the information may be transferred to the computer for straightfor
ward analysis before the systems software is fully operational. In this
way, an array of gains and timing parame ters may be evaluated for second
order corrections. Just as in many commonly used minicomputers, data in
the 3001 is organized into 16-bit words. The 2301 allows this memory to
be written into from the CAMAC Dataway. The data loaded into memory is then
automatically displayed without the need for expensive storage display or
the requisite CPU time required to refresh a standard CRT.
An increment feature allows any channel of the 3001 to be incremented by
1. This feature allows use of the analyzer as a histogram and display module
without significant core usage for data storage or software. Since the display
is continuously active, the experimenter may watch the spectrum accumulate
without significant CPU overhead.
The Model 2301 contains an Incrementing Address Register which may be loaded
from the CAMAC Dataway. The value contained in the register is used to address
memory for both read and write operations. After the read or write operation
is performed, the register is incremented by 1. Using this scheme, data
may be transferred to or from the qVt memory at the rate of 1 word
per CAMAC cycle.
For direct digitizing of photo-multiplier anode current pulses. No-charge
sensitive preamp is required, permitting high counting rates and pile-up
For use as a conventional Pulse Height Analyzer. Accepts positive
voltage signals or dc levels.
For Start-Stop timing measurements. Not multi-scaling. No TAC necessary.
Model 3001 qVt Multichannel Analyzer
Analysis Modes: Q: Current integrating (charge sensitive); integration
interval 20 nsec to 1 µsec; full scale, 256 pC ±10% sensitivity,
.25 pC/channel. V: Peak voltage; input signal rise time, 50 nsec; full scale,
+1 V or +10 V ±10%; resolution, 1 mV or 10 mV/channel; external gate
width, 100 nsec minimum to 1 µsec or switch selectable 5 µsec
maximum. T: Time interval (Start/Stop); full scale internally switch selectable,
102 or 1024 nsec ±10%; resolution, 100 psec and 1 nsec respectively.
Number of Channels: 1024 (10-bits); 256 (8-bits) in quadrants; overflow
counts are stored in the last address of the selected memory segment.
Memory Size: 16 bit - 1 per channel (65,535 counts).
Digitizing Time: 12 µsec +0.05 µsec/channel.
Temperature Stability: ±.03% of full scale/°C.
Long Term Stability: ±0.2% of full scale/week, maximum.
Integral Non-linearity: 0.25% of reading 2 channels.
Channel Intensification: Every 10th or 50th channel, front-panel
Packaging: #2 width, RF-shielded NIM-standard module, conforming to
specifications outlined in AEC Report TID-20893.
Voltages Used: ±24 V, ±12 V. (Note: a rear-panel switch
permits operation from ±6 V (if available) instead of ±12 V.)
Current Requirements: For ±6 V operation; 260 mA at +24 V, 500
mA at -24 V, 150 mA at +12 V, 150 mA at -12 V, 2200 mA at +6 V, 510 mA at
-6 V. (Note ±6 V requirements add to the ±12 V requirements listed
above if the ±6 V option is not used.)
Front-Panel Connectors: BNC.
Analog Input (Q and V Modes): Direct-coupled; 50 ohm impedance, 93 ohm
option in V mode; protected to ±100 V for 1 µsec; linear range,
0 to -1 V in Q mode, 0 to +10 V in V mode.
External Gate/External Trigger/Start/Internal Gate View: One common
front-panel connector; functionally controlled by trigger mode switch; requires
-600 mV signal into 50 ohm.
Q and V Modes: In External Gate (EXT. GATE) mode, the gate width
is equal to the duration of the gate pulse applied to this connector. In
External Trigger mode (EXT. TRIG), the internal gate is triggered by the
leading edge of a fast NIM signal applied to this connector (minimum trigger
width, 10 nsec). In Internal (INT) mode, the inter nally-generated gate
may be viewed at this connector. Amplitude ~ 100 mV.
Q Mode: Usable gate duration, 20 nsec to 1 µsec.
V Mode: Minimum duration, 100 nsec. Maximum duration, 5 µsec
(gate must enclose peak of input signal to be measured).
T Mode: The leading edge of Start input begins the start-stop time
measurement; minimum pulse width, 10 nsec.
Operating Mode: One of the three analysis modes (Q, V, or T) is selected
by a 3-position switch.
Trigger Mode: A 3-position switch selects internal trigger operation
(INT), External Trigger operation (EXT TRIG), or operation via an externally-applied
gate pulse (EXT GATE).
Continuous/Stop at Overflow: A 2-position switch either permits continuous
data collection and display or limits each channel to a full scale capacity.
Intensify: Either every 10th or 50th channel is intensified on the
display, determined by a front-panel 2-position switch.
Display LIN/LOG: Selects linear or logarithmic display.
Start/Stop: Front-panel, two-position, spring-return toggle clears
all memory and register. Start/Stop switch must be simultaneously placed
in stop position.
Memory Select (Full-1/4-2/4-3/4-4/4): In the Full position, all 1024
channels accept and display input data. In the 1 /4 position, the first
quadrant (256 channels) accepts and displays input data. Full-scale range
settings remain the same (i.e., 256 pC, +1 V, and 102 or 1024 nsec); similar
for 2/4, 3/4, 4/4.
Vertical Gain: In LIN (linear) mode, an 8-position switch selects
a maximum number of counts to be displayed per channel, between 512 and
Q Input: Analog input; 50 ohm impedance; DC-coupled. Accepts input charge
of 0 to 256 pC. Protected to ±100 V.
V Input: Analog input 50 ohm impedance (93 ohm optional). Accepts
input voltage of 0 to +1 V (with switch selec tion 0 to 10 V range). Protected
to ±100 V.
Gate Input/Output: Multifunctional connector. Acts as trigger or
gate input/output in Q or V mode. Acts as start input in T mode. Input impedance
50 ohm. Accepts NIM fast signals. (See detailed specifications.)
Inhibit/Stop: Accepts fast NIM signals. Acts as inhibit in Q or V
mode & stop input in T mode. Impedance 50 ohm.
Threshold Test Point: Reads 1000X preset threshold value in Internal
Internal Gate View: Internally generated gate is available for oscilloscope
monitoring on the Gate Connector when Internal Trigger is selected. Amplitude:
Internal Gate Test Point: Internally generated is available for oscilloscope
monitoring when the Internal or External Trigger mode is selected. Amplitude,
Busy: TTL low level output during conversion time.
Horizontal Out: Horizontal deflection voltage for CRT proportional
to channel number; 0-5 volts for full or quadrant display. Minimum load
impedance 1 kohm.
Vertical Out: Vertical deflection voltage for CRT proportional to
number of counts. Linearity ±0.2% of full scale. Full -scale output
of 5 V corresponds to 200 db/V in the log mode. Minimum load impedance 1
Connector Type: 44-contact card-edge connector; TTL levels.
Memory Overflow (22)
External Enable (4)
External Memory Address Latch (R)
Memory Enable (21)
External Load (N)
External Read/Write (M)
Incrementing Register (P)
16 Data bits (6-20)
Model 2301 Interface for qVt Multichannel Analyzer
Inputs and Outputs: 44 on a single front-panel edge connector. Pin-for-pin
identical to the qVt rear I/O connector.
LAM Button: A front-panel push-button sets the L level to true. Intended
to allow a manual interrupt.
Packaging: In conformance with CAMAC standard for nuclear modules
(ESONE Committee Report EUR4100e). RF shielded CAMAC #1 module.
Current Requirements: 500 mA at +6 V.
Model 2301: QVT CAMAC Interface
Model 3001: QVT MCA
Model 3031: QVT NIM Interface
Model 1691B: PC Interface Card (for 3031)
Q: A Q = 1 response is generated in recognition of an F(2), F(16), F(17),
or F(25) command only if a valid address (0 to 1023) is contained in the
Internal Address Register. A Q = 0 response applied for all other function
X: An X = 1 (Command Accepted) is generated when a valid F and N
L: An L = 1 Look-At-Me signal is generated by pressing the front-panel
LAM Button. The condition persists until an F(2) is received.
CAMAC FUNCTION CODES
F(2): Read qVt data from the channel whose address is in the
Incrementing Address Register to Dataway lines R1 to R16. Advances the Incrementing
Address Register by one.
F(9): Clear qVt. Clears all 1024 memory locations.
F(16): Write into qVt memory channel whose address is in the
Incrementing Address Register. Ad vances the Incrementing Address Register
F(17): Write into Incrementing Address Register. The data contained
on the Dataway lines W1 to W10 are written into the Incrementing Address
F(24): Stop qVt. Issues a STOP command to the qVt.
F(25): Increment qVt. The data in the address contained in
the Incrementing Address Register is incremented by 1.
F(26): Start qVt. Issues a START command to the qVt.
Copyright© September 1995. LeCroy is a registered trademark of
LeCroy Corporation. All rights reserved. Information in this publicaction
supersedes all earlier versions.