It was 1957 and atomic weapons tests were being carried out at Maralinga in Central Australia. The fact that the effects of radio-active fallout were not well known was shown by the instruction to those on the ground to turn their backs when the explosion occurred. The presence of Aboriginal people living in the surrounding area appeared to be ignored.
At that time, Peter MacCallum Clinic had an energetic Scotsman as head of the Physics Department. He was concerned at the possible fallout from the Maralinga tests, as strontium-90 was one of the by-products of atomic fission. It is sufficiently similar to calcium that any residual strontium can lodge in bones and possibly cause bone cancer. For Dr. Martin, that was enough data to make testing for fallout, even as far away as Melbourne, an appropriate project for a cancer clinic.
At that time, Peter MacCallum Clinic had an energetic Scotsman as head of the Physics Department. He was concerned at the possible fallout from the Maralinga tests, as strontium-90 was one of the by-products of atomic fission. It is sufficiently similar to calcium that any residual strontium can lodge in bones and possibly cause bone cancer. For Dr. Martin, that was enough data to make testing for fallout, even as far away as Melbourne, an appropriate project for a cancer clinic.
He entrusted the carrying out of the weekly aspects of the project to me, the most junior of the five physicists and in my first year.
The workshop men at Peter Mac constructed a revolving arm on a four-legged stand and this was placed on the rooftop of the Little Lonsdale Street building. Cheesecloth ‘sails’ were clipped to the arm. A month or two later, a water collection was organized.
Each week, the cheesecloth needed to be replaced and the rainwater collected. This required going up in a lift three or four floors, a short set of stairs, out onto the roof and up a small ladder. No wonder I’d been given the job!
The workshop men at Peter Mac constructed a revolving arm on a four-legged stand and this was placed on the rooftop of the Little Lonsdale Street building. Cheesecloth ‘sails’ were clipped to the arm. A month or two later, a water collection was organized.
Each week, the cheesecloth needed to be replaced and the rainwater collected. This required going up in a lift three or four floors, a short set of stairs, out onto the roof and up a small ladder. No wonder I’d been given the job!
The cheesecloth and water were taken back to the lab where the cheesecloth was burned, the water evaporated and wiped out and burned and any radiation from the two sets of ashes was measured by a Geiger Counter and recorded. These weekly readings were taken for about eighteen months.
The results were significant. The background count for rainwater was 6 counts/minute. On the week ending 24th. October 1957, the measurement was 600 counts/minute. These peaks occurred two or three times, each time being about a fortnight after a test.
The results were significant. The background count for rainwater was 6 counts/minute. On the week ending 24th. October 1957, the measurement was 600 counts/minute. These peaks occurred two or three times, each time being about a fortnight after a test.
Dr. Martin invited me to give a paper on this project at a Radiation Biology conference. An interesting experience to be speaking in the Public Lecture Theatre at Melbourne University when I’d been a student there only two years before! There were a couple of questions at the end from prominent people but our case was pretty water-tight.
Twenty seven years later in 1984, an article appeared in ‘The Age’, headed
‘A-test equipment faulty’.
‘A former government advisor said that measurements of radio-active fallout at Maralinga had been inadequate. The fallout estimation had been based solely on ground level measurement using sheets of ‘sticky paper’ that collected radio-active dust and battery-powered pumps that trapped fallout in filter papers.
Twenty seven years later in 1984, an article appeared in ‘The Age’, headed
‘A-test equipment faulty’.
‘A former government advisor said that measurements of radio-active fallout at Maralinga had been inadequate. The fallout estimation had been based solely on ground level measurement using sheets of ‘sticky paper’ that collected radio-active dust and battery-powered pumps that trapped fallout in filter papers.
'The Age', Tuesday 6 November, 1984
The cross-examination revealed some of the papers lost their stickiness due to heavy rain and the air pump became clogged with dust. The batteries also usually failed after 12 to 24 hours.
These could have led to underestimation of fallout from the tests.’
I had a smile.
Carmyl Winkler
July 2024
These could have led to underestimation of fallout from the tests.’
I had a smile.
Carmyl Winkler
July 2024
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