NRD Instruments was located at 6429 Etzel Avenue in St. Louis, MO in 1956. In 1957, NRD Instruments was a subsidiary of the Nuclear Corporation of America (known as NUCOR).

The company offered the Model CS-30 which was a beta gamma survey meter. It had a magnesium case and weighed 5 lbs. The range scale was 0.2, 2, and 20 mR/h. The unit is similar to the unit originally designed by Brookhaven National Laboratory on Long Island, New York.

NRD Instruments Model CS-30 1956

The Model CS-40 was developed in 1956. It was also know as the “Powder Puff Cutie Pie”. The unit was a wide range survey meter with four decade ranges from 20 mR/h to 20 R/h. It has a thin plastic ionization chamber that can be easily replaced if contaminated. The chambe resembles the container in which powder puffs are sold. The chamber is a detachable plastic cup which transmits energetic beta as well as gamma. The center electrode is a graphite coated ¾” diameter bakelite tube. The chamber volume is 550 cc. It has a single switch to turn on batteries and select ranges. The “wait” position permits heating the cathode of the electrometer tube before applying positive potential to the other electrodes. Warm up time is 15 seconds. The case is made of cast magnesium. The unit weighs 5.25 lbs. The unit was used extensively at Brookhaven National Laboratory since 1955.

NRD Instruments Model CS-40 1956

The CS-40A was an ion chamber introduced in the late 1959. It was completely transistorized. It had five ranges from 5, 50, 500, 5000 and 50000 mR/h. The chamber is filled with air and open to the atmosphere.

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NUCOR Model CS-40A

The Raychronix Model D-6 Samson was an alpha meter introduced in 1957. The Samson was developed in the early 1950’s and was a modified version of the Zeuto. The unit was an ionization chamber with a 100 cm2 detector area. The ion chamber is 40 cubic inches and has a 4”x4.5” pliofilm window. It has ranges from 500, 2500 and 12,500 cpm. It weighs 7.5 lbs. It has four 1.3V, one 6V, one 9.2V and seven 22.5V batteries.

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NUCOR Samson Model D-6 1957

The Model E2 fast neutron survey meter was offered in 1957. It was designed as health instrument and the response is in tissue equivalent. It measures from 0.2-10 MeV. It probe weighs only 17 oz with the circuit and meter case 6.5 lbs. Background is eliminated by a discriminating count rate meter.

NRD Instruments Model E-2 1957

The Model E-1B (AN/PDR-47A) was offered in 1959. It was a fast neutron detector with a proton recoil proportional counter. It had a range from 5, 50 and 500 mR/h. It used 10 D-cell batteries. It was 10”x 4.75” x 5-5/8” and weighed 7 lbs.

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NUCOR Model E-1B 1959

The Raychronix D-1A Ionization Chamber Cutie Pie was offered in 1959. It had a range from 50, 500 and 5000 mR/h. It weighed 2.5 lbs.