Civil Defense Museum - Radiation Instruments and Kits - CD V-457 and CD V-757 Demonstration Sets

CD V-700	CD V-710,720	CD V-715,717	CD V-718	CD V-781
CD V-750, Dosimeters	CD V-457,757	CD V-777,A Kits	CD V-777-1,2,4 Kits	CD V-755 Kit
		Radiation Kits and Instruments

CD V-457 and CD V-757 Demonstration Sets

The CD V-457 Radiological Demonstrator Unit

"Sister Mary Helene ven Horst, science instructor at Marycrest College in Davenport, Iowa, teaches students the theory of radiation and the use of radiological monitoring instruments. A 10-hour course in radiological meter reading is taught to students at the college, and a 32-hour course in radiation physics and monitoring is taught at the adult level. Marycrest College is operated by the Sisters of the Humility of Mary."

This picture is from a US government archives web site. I can't remember which one. It shows a early version of a CD V-457 set in use. Note the case on the table behind the women, the old Jordan 457 (see photo below) counter on the table and the calibrated mounting board on the table in front of the Jordan 457 counter. The CD V-700s are all early Model 3s.

The CD V-457 demonstrator set-up consists of the calibrated mounting board, absorbers, radioactive source (C-cell battery shows where the source goes in the photo) and the GM probe from the CD V-457 counter attached to the bracket at the end of the board. Aluminum square absorbers are shown in the photo. The set I have is missing the lead and cardboard square absorbers and all of the cylindrical absorbers. The cylindrical absorbers were for placing around the GM tube. The demonstration would have the different types of absorbers placed in between the GM tube and radioactive source to show how the different materials blocked or didn't block the radiation from the source.

My Partially Complete CD V-457 Set

This is as close as I can get to duplicating a demonstration with the CD V-457. I used my trusty turn and bank aircraft instrument with the radium painted face in place of the original source. The left photo shows a 300cpm reading with no absorbers in place and the right photo shows a slightly lower 260cpm reading with 14 aluminum absorbers in place. The aluminum absorbers don't do much to block the gamma coming off of the face of the indicator.

The above left photo shows a Jordan Model 457 and a later Nucleonic Corp. of America CD V-457 Model 2. The Jordan unit doesn't have a "CD V" number on it. This Jordan unit appears to be the same type of 457 in the photo at the top of this page. I wondered for the longest time what model of 457 was in the photo at the top of this page until I found this Jordan 457 unit. It's obvious that the counter in the photo is different than the light blue case CD V-457s.

The above right photo shows a couple of CD V-457s. The one on the left in the photo is a Model 3A and the one on the right in the photo is a Model 2. The Model 2, 3 and 3A are all identical on the front. This counter is a table-top model that operates from a 115 volt wall plug. It uses the same probe and Geiger-Muller (G-M) detector tube that the CD V-700 uses.

Here is the case with the top tray latched into the lid. The CD V-457 counter stores in the space to the left. Just in front of it is storage for the CD V-787 Food and Water Standards. Storage brackets for film reels are in the center. The dosimeter chargers on the right are sitting on top of a removable tray that holds the calibrated mounting board. Below that tray is storage for the square sheild and tube demonstration absorbers.

CD V-757 Barrier Shielding Demonstration Set

A very special thanks to Shane Connor at radmeters4u.com for this CD V-757 Barrier Shielding Demonstrator unit!

The CD V-757 Barrier Shielding Demonstration Set was for use as a display tool to demostrate how various sheilding meterials blocked radiation. My set is incomplete in that it doesn't have the sheilding samples or the radioactive source with it. The set originally had small round cylinder containers of dirt, wood, concrete, lead and water. The licensed radioactive source was removed by FEMA when this set was decomissioned. The set still works works great. The magnetic trianglular tags were for placement on the display to mark how much each shielding material reduced the radiation level reaching the detector tube at the top of the mast on the base. The source was inside the base and the GM detector tube is mounted in the top of mast. The GM tube has a beta sheild like a CD V-700.

CD V-757 Demostration Video On Youtube

http://www.youtube.com/watch?v=zXX-YMMgub8
I put together a short demo video of the CD V-757 in operation and posted it on youtube. I used my trusty aircraft turn and bank indicator as a source to get the CD V-757 to come to life.

CDV757 Counter, Speakers and Source Stand

CD V-757 Meter Unit and Speakers. Above Left Photo
The CD V-757 demonstration set consists of a demonstration stand with Geiger detector tube and radioactive source, a Geiger counter with a small built-in public address system, a set of small speakers, a set of shielding material samples and a large light up display system. Here is the meter unit with the P.A. speakers and microphone. My set didn't have the shielding samples with it when I got it and it didn't have the radioactive source with it either. The radioactive source was large enough in these sets to have to be licensed. The sources were removed when the sets were decommissioned by FEMA. The shielding samples consisted of concrete, earth, water, wood, and lead.

CD V-757 Counter Reading Light-Up Display. Above Right Photo.
Here is a darker photo to show the light display better. This large light up display is really one of the most impressive things to come out of the Civil Defense radiation instrument program. The purpose of this unit is so a large audience in an auditorium would be able to see the display during a demonstration. It operates in conjunction with the meter on the Geiger counter. The display has a green-sleeved flourescent tube behind a motor operated scrolling shaded film-tape which moves up and down in sync with the change in the Geiger counter display. The shaded part of the film-tape is at the top which blocks the top part of the tube. As the shaded part of the film-tape moves up in sync with the counter meter reading more of the light is exposed.