133. Stuttgart 43 Mine Detector

a. General. The Stuttgart 43 mine detector is not a detector of mines, as such, but only a locator of a radioactive material. It was frequently used to locate the nonmetallic Topfmines (par. 75) that had been laud with Tarnsand, a radioactive substance.

b. Desciption. The Stuttgart 43 mine detector (fig. 163) is an adaptation of the Geiger- Müller counter used to locate radioactive material. Four Geiger-Müller tubes, in parallel, are housed in an aluminum cylindrical search head. The toe of the serach head is closed by a threaded plastic cap. The hinged end is closed by a plastic molding which forms part of a hinge joint. The extension handle is in four tubular pieces with the lowest piece per-matently attached to the search head at the hinge joint. This lowest extension piece is made of plastic with the remaining piece made of aluminum. When dismantled, the lowest piece of the extension handle folds against the search head to facilitate packing. The extension pieces and search head are stored in a canvas case when dismantled. The am-plifying circuits and power supply are housed in the standard plastic pack case, the same type as that used with the Frankfurt 42 detector (par. 126). The control panel is on the operator's left when the pack case is in position. The control panel is the same as the control panel of the Frankfurt 42 detector except for two alterations – in the block for the headset sockets, the two upper sockets have been removed and a knob, labeled Temperaturregler (temperature regulator), for the high-tension (HT) voltage control to the Geiger-Müller tubes appears there; also, the searchhead cable socket appears on the upper part of the panel. Two standard headsets are included in the detector set. A package of Tarnsand is included in the detector set for use in adjustment of the detec-tor. The entire detector set is stored in a wooden shipping case (par. 126) when not in use. The total weight of the detector set and shipping case is 54 pounds.

c. Functioning. When a radiation particle penetrates one of the Geiger-Müller tubes, there is a small impulse of electric current. This impulse is amplified by the circuits in the pack case is heard as a click in the headset. When many radiation particles penetrate the Geiger-Müller tubes the clicks are so frequent that a continuous buzz or signal heard.

d. Operation.

(1)

Assembling.

(a)

Opening the shipping case, keeping it nearly vertical, and remove the pack case. The battery tends to lose its electrolyte if it is not kept up-right.

(b)

Lay the shipping case down and remove the extension pieces and search head from the canvas case.

(c)

Assemble the search head and extension handle.

(d)

Remove the left side cover of the pack case and insert the search-head cable plug into the rubber socket at the top of the control panel, holding the pluf with the mark uppermost. Secure the plug by giving it a quarterturn.

(e)

Plug the headset cable into the socket marked Fernhörer.

(f)

Attach the pack harness to the pack case.

(2)

Operating.

(a)

Remove the measuring stick and the package of Tarnsand from the shipping case.

(b)

Turn the off-on switch to the on (EIN) position and test the voltage with the voltage tester.

(c)

Turn the nob labeled Temperaturregler counterclockwise as far as it will go.

(d)

Set the knob on the control box so that the red dot is in the center of the opening. At this time random noises in the headset should be at a minimum.

(e)

Hold the search head horizontally over the Tarnsand at a distance of 28 centi-meters (11 inches). Use the measuring stick to be sure of the distance.

(f)

Turn the knob Temperaturregler clockwise until a strong, continuous signal is heard. A slight adjustment of the control knob may be necessary to get a stable signal.

(g)

Lift the search head; the signal should stop almost immediately.

(h)

With the controls so adjusted, turn off the detector and remove the search-cable plug.

(i)

Slide out the control box and headset cables beneath the hook on the rim of the pack case.

(j)

Replace the cover on the control panel and open the metal flap over the cable-plug hole. Push in the search-head cable plug and secure as before.

(k)

Put the pack case on your back with the pack harness, attach the control box to your belt, and put on the headset.

(l)

Pick up the extension handle and commence sweeping.

f. Sensitivity. Sweeping 8 to 10 inches above the ground will positively detect a Topf-mine laid with Tarnsand. As the search head approaches a radioactive substance, fre-quent ticks will be heard in the headset. In close proximity the ticks will seem as a conti-nuous signal. Do not be concerned about random ticks as these are caused by cosmic rays.

Figure 163. Stuttgart 43 mine detector.