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A. Detectors:
(i) 5” dia X 4”Ht NaI flat integral assembly with built in pre amplifier
(ii) An array of three pancake detectors for counting gross Beta activity.
B. Detector Bais Voltages:
(i) High voltage unit HV 502 provides required HV bias which may be in the range of 600V to 900V, for NaI integral assembly
(ii) HV for pancake detector assembly, (+900V) is provided by the PC based Beta channel counting card.
C. Pre-Amplifier for NaI detector :
Built in provides a gain of 25(approx)
Output : Positive tail pulse
Power supply : -12V from minibin and Power supply.
D. Minibin & Power supply MB403
NUCLEONIX MINIM INSTRUMENTA TION BIN is a standard Minibin designed to power Standard Nuclear Instrumentation Modules with 24-pin type of power connectors.
NUCLEONIX MINIM STANDARD INSTRUMENTATION BIN provides mounting space for 8 standard module widths of the 8 ¾ inch high type. The eight corresponding module connectors are provided with necessary wiring for distribution of all standard power supply voltages, +/-12V & +/-24V DC.
A compact Power Supply Unit enclosure is fitted on the rear side of the bin. It has all the circuits built-in to generate +/-12V @1A, +/-24V @0.5A. These D.C. regulated supplies are distributed to the eight Amphenol Connectors of the MINIM bin.
All the outputs are regulated and short circuit protected by current limiting.
E. . High Voltage Unit (HV 502) :
a. Output voltage variable continuously from 0V to 2000 volts
b. Output current (max) 1mA
c. Load & Line regulations : Better than 0.005% of full scale
d. Indefinite over load & short circuit protections and self recovery
e. Output ripple less than 20mv.
f. Dimensions : Single / Two bit module.
F. Spectroscopy Amplifier Type : SA524 is a high performance nuclear pulse shaping amplifier, ideally suited for use with all types of detectors such as germanium, silicon surface barrier and Si(Li) detectors. This is a single width NIM module with pile-up rejector (PUR), gated baseline restorer (BLR), auto threshold, diode limited unipolar output, BUSY and count-rate output as some of the key features designed into it. Some of the main applications of spectroscopy amplifier involve nuclear pulse height spectroscopy, nuclear timing spectroscopy, Counting Systems etc.
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Gain Range : Continuously variable from X4 to X1500.
Pulse Shaping : quasi-gaussian and quasi-triangular.
Shaping time : 0.5, 1, 2, 3, 6 and 10 µ sec. Input Noise : 5 mv r.m.s with 3 µs shaping time
G.Quad Single Channel Analyser Type SC 641 is essentially an integration of four individual Single Channel Analysers, a fifth additional channel having only "Integral Mode", with optimisation in electronics. The main objective of this design approach is to have stable four windows with a common reference which otherwise is not possible. Fifth channel is used for counting integral counts and this has only LLD control. Also the electronics is compressed into a 3 bit module. This is designed to serve as an integral part of 4 channel Gamma Ray Spectrometry system, used for counting U, Th & K in a geological sample.
Unit will have for each of the channels, LLD & ULD control settings manually to bracket desired energy.
Input (IN1 to IN5) :
Four [Positive unipolar or bipolar (0–10V) linear range, 0.5-10 micro. Sec pulse width, 12 V max.]
Modes :
Integral, Normal and window
Input Impedance :
100 K Ohms
Outputs :
4 V, 0.5 microsec wide TTL pulse
Window or upper level discriminator :
Variable from 0-10V when in NORMAL mode
Variable from 0-1V when in WINDOW mode
Non-linearity :
Less than 0.3% of full scale (10V) for both the discriminators Window width constancy :
Better than 30mV variation over the linear 0-10V range
Mechanical dimensions :
Three width standard module. |
H. Six channel programmble counter timer card : It is a programmble PC add on card designed to have six programmable 6 digit counters with a built in timer chip. Uner the built in control this card can receive upto a maximum of 5 inputs from Quad Analyser for counting up to five selected energy bands. Usually
First channel is assigned for K channel
Second is for U channel
Third is assigned for Th channel
Fourth is used for Cs-137 calibration channel &
Fifth channel is reserved for integral counts.
This card receives software command instructions coded in VB from the system software through serial port and the built in embed micro controller code takes the instructions performs the required function through hardware.
Stored data pertaining to each of the 5 channels can be read into the PC under software control for further processing.
This card occupies one PCI slot and the data communication for this card is through serial port configured on the beta channel counting card.
I. Beta channel counting Card :
This is a microcontroller based compact card with on board embeded software, I2C compatible counter / timer, serial DAC, serial EEPROM & HV circuit. This card can be plugged into any pentium PC having a PCI slot & is PC programmable
• User interface is through front end VB based emulation software.
• PC interface is through RS232C serial port.
• Power : +5V, +/-12V from PC slot
J.Personal computer system: Standard Pentium IV configuration is good enough for this system. The only requirement is that it should have atleast two PCI slots
K. Lead Shielding :
A 4” thick Lead shielding is provided all around the detector assembly comprising of 5”dia X 4”ht NaI detector, Pancake detector assembly & sample container, with a facility to load the sample container easily into the lead shielding assembly.
Optional Essential Accessories:
Radiometric standards for K-40, U-238, Th-232 & Cs-137 (For calibration).
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