In 1945 Heaver turned eighty. He still lived at Heavers in Ryarsh for most of the year but for the last few years John had booked him into a hotel on the south coast for the winter. Heaver was becoming a little frail, and broke his hip a couple of times, but with some help in the house, he continued to manage. The cottage at Ryarsh was old-fashioned and it worried John to see Heaver wavering up the stairs carrying a candle. To bring mains electricity to the cottage would have meant bringing a cable right up the hill from the village and besides, Heaver was opposed to this: "Why should I have to bother with all this messing about with switches," he would say, "when you can blow a candle out with a single puff?" This did not reassure John, and he eventually rigged up a system of torch bulbs connected to a car battery so that at least the stairs could be lit, but Heaver preferred to continue with his candle. He still took an interest in bacteriology and when writing to send him good wishes on his birthday, John commented admiringly that not many people were still active in research at eighty, referring to a letter Heaver had just had published in a scientific journal. John and Reinet wrote regularly to him, visited whenever possible and did odd jobs in the cottage. Reinet posted him a tin of biscuits from time to time: Heaver was to return the tin for a refill when it was empty. Frisky, the donkey Celia had loved so much as a child had lived in the meadow at Heavers for many years, but her condition was deteriorating, and just before the end of the war, she had to be shot.The war in Europe came to an end officially on 8th May 1945, and John took two days off to go up to London for VE-1- day, hoping to get some good stereo photographs of the celebrations and floodlights "to bore our grandchildren with". He wandered round London and arrived at Buckingham Palace just in time to see the King and Queen come out onto the floodlit balcony. Reinet could not join him as she was in Manchester at the time. In July, both John and Reinet supported Labour candidates in their respective constituencies in the first post-war general election, excited that there was at last hope for the Labour party, which, they believed, could best effect essential social change. Shortly before the election, John spent one evening duplicating six hundred leaflets and another canvassing. He went to the eve of poll meeting in the market square to find a crowd waiting for someone to come and speak to them. John was pushed up onto a bench and he spoke impromptu until the candidate, who had been delayed by a road accident, arrived. John's confidence at public speaking had increased tremendously since his Cambridge days and afterwards he bemoaned the fact that although there was a large crowd it included no hecklers. On the Thursday of the election, he took the afternoon off and sat outside one of the polling stations noting numbers of voters. He was satisfied that the 'beating-up' service had got practically every known Labour supporter into the Ilminster polling stations and was delighted when Attlee became Prime Minister after a striking Labour victory.
Earlier in the year, as it was becoming clear that the war was coming to an end, John and Reinet decided that they had no wish for their present lifestyle to continue. David was now three, and Reinet felt that she was missing a lot by not being with him and so made the difficult decision to resign her post, which she did in March. She was still very worried that no one suitable might be found to take over from her: she was now working from Holborn with twenty assistants and in eight years the union had increased its number of members from nine hundred to seventeen thousand. There was even a brief suggestion that John might apply for the job, but this was not seriously entertained for long; he said that he felt he needed something more restful and that he would not compare very well with Reinet anyway. So she offered to stay on until a new Secretary was found, which did prove quite difficult and it was not until the beginning of July that the Executive recruited a replacement. The period of waiting was very hard on John for he had pinned all his hopes on their being able to live together properly again soon. When at last Reinet was able to report to him that she had a definite leaving date he wrote back saying that if only the Executive had made their decision earlier, he could have enjoyed their recent holiday so much more. Reinet eventually left in August; a reporter from the Daily Mirror interviewed her and wrote a short article on the work she had done, which the paper published under the headline 'Bride won £ 80,000 pay rise for our scientists'. Reinet objected to this headline, saying that the fact that she was newly married was totally irrelevant.
Meanwhile, deciding what he should do was not easy for John. Mr Gibson's memos exhorting him to maintain industrial secrecy even during the war still rankled, and John knew that when the war ended competition would return at full force. He had no wish to do research that would, by being first, mean the waste of all the research in the same field by other companies; he had even less wish to find that, in a repeat of the scene with the S22A valve, his own research had been of no value because someone else had patented the same ideas first. He felt strongly that he wanted the freedom to discuss the science he was doing with others. Then a reliable leak told him that Mr Ullrich (who had come to STC to be in charge of the velocity modulation laboratory when France collapsed) would be going back to Paris and John was in line for his job. John saw this as sitting in a nice room with a carpet and commenting on other people's work, which he knew was not for him.
During the last years of the war, John had visited a number of research groups, which had made him consider other job possibilities. He had always been envious of Stan Tomlin, who had been drafted in from a lectureship in the University of London and would be returning to this at the end of the war, but he had no idea of how to get a University post. It was Reinet who suggested that he should write to Professors Feather, Dee and Oliphant whom he had known at Cambridge before they had taken chairs elsewhere. She encouraged him by saying that she didn't mind at all if this meant a reduction in salary. John put a lot of thought into his letters, sending drafts to Reinet for her approval. Professor Oliphant wrote back that he could offer him a lectureship starting at £ 500 per year and invited him to come up to Birmingham for an interview.
In 1937, Mark Oliphant had left Cambridge for Birmingham University to take up the Poynting Chair of Physics. His job was to oversee the building of a sixty inch cyclotron-2- . During the war he put that project on one side to join the national effort on radar and then in 1943 he went to the United States to join the Manhattan Project to work on the atomic bomb but now he was back in Birmingham concentrating on the cyclotron. Soon he was also working on the world's first synchrotron-3- . John had kept in touch while Oliphant was working on radar, having been sent to visit his department a couple of times by STC.
Professor Oliphant invited John to come to Birmingham for an interview on a date that turned out to be VJ-4- day (August 15th). When John arrived, the Physics Department was almost empty, which made him wonder if he had the right day. It turned out that everyone was out celebrating so he rang Oliphant's home, and the Professor came in to see him. But John felt uncomfortable when it became apparent that a Mr MacFadyen was to be taken on for the lectureship that John thought he had already been promised. John did not suffer for long, for Oliphant soon told him that he was going to employ him as a Research Fellow, which would involve helping with the cyclotron construction work. Joining Reinet in London that evening, he was able to tell her that he would be earning a grand £ 750 per year.
The next hurdle was to resign his post at STC. He talked first to Mr Ullrich and then to Mr Gibson, attempting to soften the blow by insisting that it was industry in general he wanted to leave, not STC in particular. Mr Gibson did everything he could to persuade John to stay offering him a position in a branch nearer London and imploring John to tell him what he wanted so that he could get it for him. John was adamant that he really did not want to stay and left Mr Gibson in an upset state. He then sent in a formal resignation to STC, which led to an invitation from STC's General Manager, Mr Spencer, to come to the London office, bringing Reinet too. Mr Spencer was very welcoming and asked after David. Getting down to business, he offered John a rise to a thousand pounds a year. John then asked why, if he was now worth such a salary, he hadn't been earning more than five hundred and fifty pounds plus a war bonus of a hundred pounds. Mr Spencer said that it took a bit of time to recognise potential value and went on to offer Reinet a job for as long as she should want one. John felt that the belated salary offer was another very good reason why he did not want to work in industry any more. So he made it quite clear that he would still prefer a university post despite the salary difference and Mr Spencer had the sense not to go on arguing but expressed the hope that John would enjoy his new job, adding that if at any time in the next few years he felt like returning to industry there would certainly be a job waiting for him.
John then had a month to work out his notice and finish off his current experiments in the STC laboratories. Reinet was also finishing off at the AScW but took two days off to go and look for lodgings in Birmingham. This was very difficult as demobilisation had started, and there had been no new houses built during the war. She tried agencies and acquaintances without any luck, but eventually Mrs Peierls, whose husband R E Peierls was a professor at the University, let her know that her daily woman had mentioned a couple of old ladies in Kings Norton (a Birmingham suburb about three miles from the University) who wanted to let two of their rooms. Reinet dashed over to their house and booked the rooms, a bedroom into which the three of them would just fit, a small sitting room and a share of the kitchen and bathroom. Almost as soon as they had moved in, Reinet was out walking the streets again with David, following up every advertisement for a flat in the first edition of the evening paper each day.
John started work at the beginning of October, and found that he was joining a very small team who had started the work on the cyclotron before the war together with several others who had also been taken on recently and knew even less about the accelerator's structure and operation than he did. After a lot of reading and numerous informal colloquia, they all became more confident and developed a passion for the work they were doing. Writing to his father, he described a cyclotron as: "a machine for persuading atomic nuclei to move extremely fast, and my job is to help with the final construction of one .... and then of course the machine will not work at first, you can always be sure of that". In fact the cyclotron had been invented in 1930 in the United States by Professor E O Lawrence who later received a Nobel prize. Two hollow D-shaped electrodes (called dees) are mounted inside a vacuum tank, and connected to a high frequency voltage supply such that an alternating electric field acts across the gap between the dees. Perpendicular to the dees is a strong magnetic field. The forces supplied by the alternating electric field and the magnetic field act on charged particles injected into the centre of the tank to make them follow a spiral path. Each circuit of the tank takes the same time, so as they get further from the centre they speed up. After about two hundred and fifty turns, the particles reach a speed of up to two hundred and fifty thousand kilometres per second and are deflected onto a target for experiments on nuclear reactions or for manufacturing various isotopes.-5- John started a series of notebooks in which he wrote down his own researches into the mathematics, physics and various aspects of engineering of a cyclotron under such headings as 'Mechanical strength of D brackets', 'Initial paths of protons in the cyclotron' and 'Condition of resonance of multi-section transmission lines'. He jumped from one subject to another as the technical and workshop staff asked for instructions and as fresh ideas on the theory came into his mind. He had learnt the basic principles of machine drawing from his draughtsman at Eltham, and set up a drawing board in his office on which he produced tracings of pieces of equipment for the workshop to make.
The Birmingham cyclotron had been designed as a slightly scaled-up version of the latest American one. Some major parts had been constructed before the war started, including the bronze casting for the main vacuum tank, and the dees. The main magnet (a four hundred tonne monster) had been assembled during the war when it was thought that the cyclotron could be used in experiments on the separation of Uranium-235 for an atom bomb, and a second-hand direct current generator for it had been obtained from Liverpool where it had been supplying power for the trams. There was still much building and assembly work to be done however, by the time John started work at the university.
John was immediately at home with all the team he was working with, a team which could have got nowhere without Mr Cornick the chief laboratory technician and Mr Robinson who was in charge of the workshop. Professor Oliphant was always good-humoured and had the ability to think unconventionally; when he had installed his generator, he wanted to test it but could not find a suitable resistor, so he obtained some hundreds of 100 watt light bulbs and rigged them up in parallel to do the job, lighting up the cyclotron pit beautifully. (An apocryphal story emerged later that he had connected the generator up to the perimeter fence.) One day, the five tonne vacuum tank, which was supposed to be supported on pieces of wood across a hole, fell through, producing rather a mess. When Professor Oliphant arrived on the scene, he burst into laughter, a deep and infectious "ho-ho-ho". John was delighted to hear that Oliphant was refusing any grant given on condition that resulting publications had first to be approved by a government department, something he had had quite enough of during the war.
Less than a fortnight after starting work at Birmingham, John had a third cycling accident when a tram caught him up and tossed him over a parked car. His bicycle was crumpled by the impact, but he was not hurt until he hit the road on the other side of the car, breaking his collar bone. The accident happened very near to the University gates, so he picked himself up and went in to apologise to Professor Oliphant who drove him to hospital to get the broken bone set and bound up. This meant that his right arm was inoperative for six weeks but there was no way that John was going to let this stop him working at a stage when his study of cyclotron theory was going so well. He needed to be able to write, and he had discovered years ago in Cambridge that writing with the left hand was easier if it was done in mirror image while writing from right to left. To make this more readable, he put a sheet of carbon paper against the page to be used and wrote on the back of the page with a wooden point, which caused a mirror image of his writing to show on the front. The result was a little uneven but perfectly readable. He wrote like this in his notebooks, on signed memos asking the workshop to make equipment and in letters.
The hunt for a flat or house was not going very well despite all Reinet's best efforts. Then John heard of a couple who were leaving the University and vacating a flat consisting of the two upper floors of a house in Grove Avenue, Moseley and he snapped this up immediately. Before they moved, Reinet made several trips transferring rucksacks full of their coal across. It had no hot water tank and so they carried buckets of water from the kitchen clothes boiler whenever a bath was wanted.
Another reason why John and Reinet had wanted to be back together again was to be able to increase the size of their family. Reinet had fallen pregnant as easily as before (there is a reference in one of her letters to VJ day falling at the right time) but soon after moving into their flat she started a miscarriage. She had been having a very hectic and physically demanding time since they had arrived in Birmingham particularly since John's arm had been out of action, although she did not herself consider the latter to be the cause. She was whisked by ambulance to Dudley Road hospital where she waited until next day for the miscarriage to complete itself, not even knowing where she was as the name of the hospital meant nothing to her. Early on the first morning, she discovered that those patients whose visitors had brought them eggs the day before got them for breakfast.
Two days after she got home she started a haemorrhage and had to be re-admitted, but this time equipped herself with some work to keep her occupied: John was working on theoretical aspects of the shape of the cyclotron dees, to determine whether they should be D-shaped, or whether they should be cut away to the wedge shape of a very big slice of cake. He had just reached the stage in his work where a large number of repetitive calculations were needed, to apply two formulae he had developed to each possible angle at the point of the wedge: he knew that a bigger angle meant that more power could be developed and a smaller angle that there could be greater acceleration of the particles. So Reinet took his formulae, paper, pencil and a book of log tables with her and she sat up in bed performing all the calculations and tabulating the results, a job which nowadays would be done in an instant by a computer. Then she drew two graphs that showed exactly the optimum angle for the point of each wedge. It was too late for the Birmingham cyclotron team to have dees of this shape immediately, because theirs were already made, but twenty years later, when some other alterations were being made, new ones of John's design were installed. However, John published his theory in 1950 in a general paper entitled Cyclic Accelerators, and ten years later an American cyclotron was fitted with the new shape of dee as were all new cyclotrons from that time on. Text books, on the other hand, mostly never caught up and still illustrate dees as D-shaped.
While Reinet was out of action, Peggy Robertshaw visited for a while to help look after John and David and later Celia came up from London with young Nicholas for some part of Reinet's second stay in hospital. One evening she was looking around for something helpful to do when she found a box of men's socks that appeared to need darning, so she worked her way through them. Then she found another box and then yet another. John and Reinet had moved to Birmingham before John had got round to his usual chore of patching socks, which he did at the beginning of each winter, and neither John nor Reinet had had the time or the inclination to do anything about them since!