Nuts & Volts - September 2004

Near Space

However, I do not

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recommend you do this, as I may have been ¹⁰⁰⁰⁰⁰lucky.

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I like to solder the wires of the telephone ⁸⁰⁰⁰⁰cable to a straight male ₇₀₀₀₀header with 0.1” between centers. This type of ⁶⁰⁰⁰⁰header is available from ₅₀₀₀₀Jameco as part number

Altitude (feet)

109575. I tin each wire ⁴⁰⁰⁰⁰and then slide thin heat ₃₀₀₀₀shrink tubing over it.

Next, I tin the short ²⁰⁰⁰⁰pins in the header and ₁₀₀₀₀

press a tinned wire in contact with a header pin and ⁰

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heat them with a soldering iron.

The solder on the wire and the header pin melts and fuses the wire to the pin. After it cools, I slide the heat shrink over the soldered connection and shrink the tubing. Afterward, I can plug the RM- 60 into the BOE’s breadboard or my flight computer, like I would a servo.

I use the following code to determine the counts per minute from the RM- 60. My code is written for the BS2pe, so you will need to modify the count time if you use a different flavor of BASIC Stamp. On my flight computer, I store the results into a RAM Pack B. If you are sending up an RM- 60 with your BOE, then you can store the results in the EEPROM of the Stamp. After recovery, you can download the results of the flight.

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Flux (cpm)

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Figure 4. Cosmic ray flux.

gm
radiation

CON
VAR

0
WORD

Geiger_Counter:
  COUNT gm,34843,radiation
  DEBUG DEC radiation

ray showers. There really are fewer cosmic rays to detect, but each detection on average contains more energy.

Had this flight occurred shortly after a solar flare, the cosmic ray flux most likely would have continued increasing above 62,000 feet. If the mission had taken place closer to the geomagnetic poles, the increase in cosmic ray flux would have climbed more rapidly.

So, get out there and start using the RM- 60. For $150.00, it’s a great little Geiger counter. I do not work for Aware Electronics and I don’t receive compensation from them. I’m just a satisfied customer. Let me know how your Geiger counter experiments turn out. Remember that you can contact the amateur near space group closest to you and arrange for them to carry your experiment into near space.

Onwards and Upwards, Your Near Space Guide NV

This code assumes the RM- 60 is connected to P0 and counts the number of pulses from the RM- 60 for 10 seconds. Since I have so many other experiments onboard my near spacecraft, my flight computer can

SEPTEMBER 2004

only afford to count cosmic rays for 10 seconds at a time. After recovery, I download the results from the Geiger counter into a spreadsheet and multiply the results by six to get the cosmic ray flux in units of counts per minute.

In your experiments, you should count cosmic rays at a fixed interval. Use the APRS data from your near spacecraft to determine the altitude at each measurement. When you combine the cosmic ray count with the altitude in a spreadsheet, you generate a chart like the one in Figure 4. It shows data that was recorded and collected at the Great Plains Super Launch on July 3, 2004. My near spacecraft weighed nine pounds and made an altitude of 104,571 feet on a 1,500 gram balloon with 15 pounds of lift.

This chart is typical of what my near spacecraft measure. The flux increases with increasing altitude, as Viktor Hess would be familiar with. The cosmic ray flux increases until an altitude of 62,000 feet is reached. Higher than that, the cosmic ray flux decreases. t appears that the drop in cosmic ray flux occurs because the near spacecraft enters a region where there are primary cosmic rays that have not yet produced cosmic