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2.3 INSTRUMENTATION
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2.1.1 Gamma--Intensity-Time Revordezs (GITR’s). ‘These iristeaments consist of two re-
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@ose rate. The nominal dose vate range td 9 rer,hr to 67,009 /hr.
These tatts were shock-mounted withthe ceater ofthe chamber sensitive volume 3 i<2t abive
the deck. Coolicg colts were provided aro-ud the electrometer case when units were tectat ied
ia high-temporstve comportments (Figure 2.1).
A detailed duscrimion of these units and the calibration techajques wsedjis svallatie in Reterence 18
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2.3.2 Total Sie Sarspler. The samplivg Sead (Fuute 323 for Gis jeSty acrent Coutatand
12-Inch-Ciametcr fiticr uni, A pre-filrer ef Hollingeworth wnt Vewe Nu TO deter parc a4
Mins Sciety Appiisuce 7199 Liter paper, backeldiy ¢ Millinor> fitee and sueeried 63a wire
sereew, was ised An allow ef 10 nn (ole) srs -maistaiond ty an DU. cvectnr ti" ve
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buclion unid /Pigure 2:2) Cove hoped for use G ring Operation Cusle ene civertted in Reerence
‘6. ‘false sc:apler was inteoacd ta epeecic-ece timoguely trem 2E--% to 11+ 69 micas
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eyeling concentric ionization clambers wit electrometers, cersectet by a cable to a bsllerypowered inagotic tape recorder unit that includes a timiag device. Pulset for a given garoma
dose increment are recorded as on-ntf information an two tape channels, and timing pulses are
recorded on a third channe). Thus the time between pulses or pulse frequcary isa mescure af
Airflow calibration was zecomplighed La achutrient of the constan?-Clom cesindi Ware a:seh”
‘using a calitvaled Flowrator to measure airiics. The Ficeraior is-2 metericg device Coulyned
to measure fluid flow rates (Stabl-Via Flowrzier, Fisher-Por ier Co.).
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The total air sampler was notshecicmersied. The sucticy unit was mooted ie a scardy
- gonventent location and was conaacted to fhe camaplling head bo PressureNes base. The gampling head was mounted ona pipe stand, with the orifice zpproximaicly 2 feet above (he dack.
2.1.3 Incremental Afr Samplers. These consisted of tarec basic units: (1) 2 comstanl-flow
suction unit, (2) a Ledex solencid-opercted indexing head connected to a valve in a 10-p0rd
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* manifold, and (2) a group of 10 Andersen sampling heads. The solenvid ves con‘roliod by a
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timing circuit to sequentially cpen the 10 ports in the maxifoid at preset time intervais. By
this means, one suction pump pulled air ia turn through each of the 19 Arderee:nsamplizg
heads. A timing circui falivre reeulied in the useof only one samoling head at each installation; ther<fore, this descri;tion will beco:tined to'the Andersen 2empling head and suction
unit, though the name “incremental famyier” will be used thronz!. < the report to identity
this 2ir sampler.
“The Andersen sampling head, 2s modified tor Project 2.2, consists of fire stages with aa
_ elbow added above the entrance orifice to prevent material from falling into the firststage
" (Figure 2.4). Each of the first four stapes consists cf a perforated metal plate. -The particle- laden air ts drawn through the holes, producing a jet of air against a filtcr poper on a pizte
below. Deposition of the particles on the filter is dependent upon the size, density, 2x3 velocity of the partscie.
The air then pasocs over the edge of the eclieetioa plate arc inte the neat
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stage. The hoiv size in the perforated Piates is smaller in each succeewing singe, pre-doring