Administrative Procurement Branch, Environmental Protection Agency, Fairchild Building -- 7th Floor, 499 S. Capital Street, S.W., Washington, DC 20024

66 -- HIGH PURITY GERMANIUM DETECTOR IN A ULTRA LOW LEVEL BACKGROUND CONFIGURATION WITH A LOW BACKGROUND LEAD SHIELD SOL 97-4 DUE 072597 POC Rodney P. Magee, Contracting Officer, (202) 260-6455 E-MAIL: Rodney P. Magee, Contracting Officer,, Magee.Rodney@epamail.epa.gov. This Modification to Sol 97-4 provides additional information as to the specifications for the Germanium Dectector. The specifications for the elements of this detector are as follows: 1) The detector must be of High purity Germanium (HPGe) coaxial. The contacts are diffused lithium and implanted boron. 2) The end cap must be fabricated and designed to ensure high geometric efficiency and made from 99.999% pure Aluminum. The uranium and Thorium composition must contain less than one part per billion. The end cap will be constructed seamless to ensure long reliability vacumm integrity. The end cap will alloow for depth of Marinelli configurations and no interferences. The end cap will not exceed 3.75 inches in diameter. 2) The vacuum chamber will be fabricated from 99.99% pure copper. If copper can not be utilized than Stainless steel may be used. A detailed content of gamma emitting nuclide purity of the stainless steel will be submitted to the buyer (end user) for verification. 3) The detector mountcup and components will be constructed of high purity copper which provides excellent contact with cooling rod (cold finger). The detector to entrance window should be nominally set to 3mm. 4) The preamplifier on the J-type or U-style cryostat will be remotely located for a ultra low background configuration. The preamplifier is mounted outside the shield and attached to the dewar as to not to intefere with ultra low backgroudn configuration and operation for installing or removing detector from shield. Safety circuit for temperature sensing automatic high voltage shutdown on HPGe. The preamplifier will have connections for High Voltage (HV) input, Test input, preamplifier power, energy output, timing output, HV bias shutdown output, and HV LED indicators. Connections on the preamplifier will allow for the user to mount existing cabling straight to preamplifier and not from cabling to cabling. 5) The Dewar liquid nitrogen (LN2) capacity 30-32 liters with a loss rate of approximately 0.5-0.6 liters per day.Setup for J-typpe or U-style integration with preamplifier mounted for ultra low level background configuration. 6) The lead shielding must be composed of four to six inches of lead for ultra low background configuration. The outer jacket must be constructed of thick low carbon steel for durability and ruggedness. Construction of shield should be low background lead and allowing for a minimum of one inch of the inner lead used to be certified low lead-210 contents by the industry standaards. The inner lining of th lead shielding will be made from high purity copper and tin. This type of liner will have no cadmium. Constructed into the lead shield will be a Nitrogen purge connection. The shielding will have a easy moving mechanical top with little or no effort of the operator to open. The support stand or table for lead shielding will pre-manufactured. All of the abovementioned items must meet buyers detailed descriptions with no protypes or beta testing options. All items listed will have a minimum of a oneyear return to factory warranty. Delivery Date of items listed is guarantedd to be no more than 90 days from ordering. Shipping is the responsibility of the seller. Written inquiries may be utilized may be utilized via facsimile to (202) 260-1929 or via E-mail to Magee. Rodney@epamail.epa.gov (0196)

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