The Alpha Hand, Foot and clothing monitor shall comprise a set of detectors and an electronic unit.
B) Clothing probe:
A) Hand probes:
• Number of monitoring channels: 4(Right hand 1 & 2, Left hand 1 &2).
•Detector Type: 235x150mm Zns(Ag)scintillator based detection unit.
• Detection Efficiency: >25 % overall forAm-241.
• Probe Construction: Each channelshall have a 235x150mm Zns(Ag)scintillation detectors. They are fittedin the instrument so that they can bedetached easily for maintenance.
• Sensitive Area: >300 Sq.cm
• Protection Grill: The whole detectorassembly shall be protected by asuitable thin metallic grill.
•Detector dimensions and performance shall conform to IEC61098 specifications.
• Number of monitoring channels: 2(Right foot 1 &, Left foot 2).
• Detector Type: 347x150mm Zns(Ag)scintillator based detection unit.
• Detection Efficiency: >20 % overall forAM 241.
• Probe Construction: Each channelshall have a 347x150mm Zns(Ag)scintillation detectors. They are fittedin the instrument so that they can bedetached easily for maintenance.
•Sensitive Area: >300 Sq.cm.
•Protection Grill: The whole detectorassembly shall be protected by asuitable thin metallic grill.Detectordimensions and performanceshall conform to IEC 61098specifications.
C) Clothing probe:
•Number of monitoring channels: one.
•Detector Type: 175x125mm Zns(Ag) scintillator.
•Detection Efficiency: > 25% overall forplastic scintillation detector assemblywith Am-241.
•Probe Construction: Hand-held type. It shall be placed on a holder with micro-switch assembly on the side of the monitor. On lifting the detector, the monitoring shall be started.
•User interface during configuration &measurement through theTFT display & optical sensorsCounting of pulses from 7 individualdetectors.
•Storage of last acquired data andlast contamination data in database.
•Configuration of variousparameters like PM time, BG time,BG dwell time, Low BG set point,High BG set point, Alarm set point,IP address, Voice & visualguidance languages, fault diagnostic configuration, detector efficiency, detector status etc.
•Generation of voice guidance messages through stereo O/P sound device during measurement cycle.
•Initiates / terminates measurement cycle by sensing optical sensors status.
High Voltage, Pulse Amplifier and Data Acquisition Unit:
This unit essentially comprises of High Voltage module, 7 channel Pulse Amplifier section, FPGA based Data acquisition board and State of Art Single Board Computer unit. DC Voltages required to bias the Electronics are generated by DC-DC convertors located on this board. Signals to/from all PMTs are routed to this unit.
Switch Mode power Supplies unit: An AC-DC converter +24V output . It is also provided with a line filter & other EMC suppression components.
7 Channel Pre-amplifier section:
This unit comprises of 7 individual pre- amplifier used for connecting the –ve tail pulses to TTL coming from each of the scintillation detectors. HV bias to the scintillation detectors is fed through the preamplifier unit.
0 to 9999 counts.
0 to 9999 cps.
0 to 999.9 Bq.
0 to 99999 cpm.
Pre-settable from 1 to 99 seconds in 1 sec steps for COUNTS, Bq, CPS or CPM modes for Hand and Foot monitoring. Time constant for checking the Clothing monitoring is 5 seconds with display being refreshed every second.
Counting Range : 0 to 9999 counts
0 to 9999 cps
0 to 999.9 Bq/cm2
0 to 99999 cpm
On Overflow the display shall indicate ‘OR’.
HUMAN MACHINE INTERFACE:
Indications & controls:
Mains switch: The mains switch shall be provided Rear sider the cabinet of the monitor.
Optical sensor: The monitor shall be provided with optical sensors inside the detector cavities for sensing personnel and initializing the counting automatically.
Visual alarm : Each channel color visual mimic indication is provided on the colour LCD TFT display.
Audio Alarm: Loud audio tone.
Audio Instructions : Audio instructions shall be generated for clear, contaminated, instrument fault, monitoring in progress and incomplete operation. Voice messages shall be played back in English.
ELECTRONIC UNIT: The electronic unit consisting of the following
a.Signal processing and displayunit.
c.Switched mode LV supplies unit.
e.High voltage power supplies unit.
Signal processing and display unit: The signal processing & display unit comprising of an SBC & large TFT display perform data acquisition & control. It carries out the following functions of
Operational Guidance: Operational guidance messages shall be displayed Before monitoring, On Clear, On Contamination and On Incomplete operations shall be generated in English.
Incomplete operation: Multi-lingual textual indication accompanied by audio alert are generated when counting is interrupted.
Clear Indication: LCD mimic indicator will be ON when all the channels are clear.
Counting in progress Indication: Busy indication will be shown while Counting is ON and Time left is displayed.
Visual display: 10.1” colour TFT display.
Given below is a partial list of the functions being carried out by the visual display.
Display normal status messages.
•Visual display of monitoring in progress (including countdown of time in seconds).
•Display of individual channel readings.
•Background checking and display
•Instructions for use.Self-explanatory, language independent symbols / user instructions.
Computer interface: The monitor has a USB port for data transfer of Acquired Data / Alarm data to a connected Pen Drive / Through Ethernet Portal Configurator App.
Power supplies: The monitor shall have a High voltage power supply unit for the detectors and a low voltage power supply unit which supplies the DC power supplies required for the Electronic unit. It shall have a very good line voltage and load regulation for all the supplies. It shall be fitted with Mains line filters to avoid line interferences.
The High voltage output shall be adjustable by handheld configurator or host PC and EHT should be displayed on the display on demand. The EHT shall adjustable from 300 V to 1500 V DC.
Instrument fault indication: Fault diagnostics are carried out periodically and any failures are reported on the display like LV, HV and detector failures. Fault indications shall be cleared automatically if normal status is resumed.
Self diagnostics : The monitor has built-in self diagnostics. On being powered it shall perform tests to ensure that all components and sub systems are functioning properly. It shall check for the Power supply, High Voltage Supply, Detector, Counting and measuring circuits, Alarm Systems, Display Systems and communication port.
Test points shall be provided for checking the EHT voltage and for connecting external input pulse signals.
•Most of the modules of theElectronic unit and detectorsshall be integrated into acolumn shaped cabinet withcastor wheels.
•The hand probes shall befitted so that both the hands canbe inserted and the opticalsensors inside the cavitiesare activated when hands areplaced to start monitoring.
•The modules shall be plug in typewith all the controls and displayon the front panel.
•The cabinet shall be rat- proof, rugged & elegant.
Input Power: 85-264VAC, 47-63Hz, single phase supply. Power ON/OFF indication is provided with an indicator LED.
a) Foot assembly dimensions: Width: 600 mm.
height: 111 mm.
depth: 806 mm.
(b) Vertical Column Height :
(c) Hand Assembly (dimension): Width: 700 mm. Height (without TFT): 186 mm. depth: 327 mm.
1687H x 729W x 895D mm.
Environment: The instrument shall be able to withstand temperature upto 50°C and relative humidity upto 90% in radiation areas.