In October the building of the base was started by creating concrete blocks on which aluminium bars can be mounted so that the detector will not be dislodged by the wind. In order to do this a mould was created as seen in the picture on the right. The block needed to be a cuboid in shape but with a metal bar imbedded within so that the aluminium support struts could be securely attached to the concrete blocks. As encasing what were effectively large nuts into the block, there was very limited chance of the aluminium bars seperating from the concrete anchors.
It was decided that only one block should be used per corner of each car box in order to minimise the gap in height between the roof and the base of the aluminium bars/car roof boxes was a little as possible in order to decrease the upthrust that would occur due to the wind going under the detector boxes and trying to force them up, off the roof. As the concrete is relatively heavy compared to the rest of the detector, all we needed for the anchors to work successfully, is for each block to have a large a mass as is sensible whilst having as small a eight as can be acheived. The constraints however was that the height still had to be long enough so that the metal rod was safely incased and could not break the block apart which would happen if the mould made the concrete slabs to thin. Also we wanted to try and keep the cost of the dry cement powder as low as possible which meant using as little as possible. This meant that the width and depth of the mould had to be margninally larger than was required to keep the blocks down and intact during normal weather conditions so that should there be an increase in weather conditions (ignoring extreme weather conditions as the chances of that occuring at the location of the detector is neglible) the detector will not be damaged.
With the mould completed the trial block was made by filling the mould half full of water and adding dry concrete powder. This worked to create a functioning concrete block, as depicted on the left, however it was not easy to mix in the powder using this method. Therefore it was aggreed that a substantial amount of concrete should be added first to the mould and then slowly incorporate the water (and extra concrete powder when required) in a method that is not to dissimilar to creating cake mix. However before the subsequent concrete block could be made, the mould needed to be partially deconstructed in order to clean and wax it so that any cement stuck to the mould was removed and so that the chance of getting more cement stuck to the mould was reduced. Once that was completed the rest of the parts of the mould could be joined back on and the next block made. The pictures below clearly show the order in which these steps were taken to create each individual concrete block.
By the end of the November, 6 out of the 8 concrete blocks had been completed (as seen on the right) and by the end of the year the final two made the collection complete. There was just enough time to mark up the aluminium bars that would be attached to the concrete blocks before the break for Christmas and New Year
The first task of the construction team for after the Christmas break was to drill through each of the four aluminium bars that had been marked in December (below). The bars were then tested by attaching them to the concrete blocks that were already built. Two knuts were removed from the block so that the aluminium bar would rest on the metal washer and the two knuts above would keep it secure. Below is a sequence of this small pahse. Once this was completed the construction was put on hold as the final aspect of this phase is to attach the aluminium bars to the concrete blocks on thr roof of the Marling DT block however this can only be done once the staircase has been ordered and constructed and there has been a dry period of weather so that the base is not constructed on a weathered surface.
In late April, the portable staircase arrived, allowing the Society to construct the base for the detector onto the roof of the Marling DT building. With the stairs in place the 8 concrete blocks (left) and 4 aluminium bars (right) were moved up onto the roof. Once they were onto the roof, the concrete blocks were seperated out into the correct places and the aluminium bars placed with them. Two of the three nuts were removed from the metal pole inside the concrete block along with the two washers. For each concrete block, the first washer was then replaced onto the block so that there were two nuts close to the concrete itself. Then the first washer was placed on top of the nuts, shortly followed by the aluminium bar. This was then followed by the second washer and then the last nut to keep it all secure. This process was repeated for each of the concrete blocks. This entire procedure can be seen in order below;
With the aluminium bars attached to the concrete blocks, checks were carried out to make sure that the bars themselves were horizontal. This was done through meticulous use of spirit levels and carefull adjustments of the aluminium bars on each concrete block. This can clearly be seen below. The purpose of this was so that when the two car roof boxes that will eventually house the detector are attached, the remain completely horizontal so that the detector equipment can work as efficiently as it is possible.
With the stand completed ontop of the roof, the ski boxes could be attached. This was acheived by first placing the car boxes on the aluminium bars and moving the internal sliders so that they are aligned over the aluminium bars themselves. Once this was done, it was just a simple matter of attaching the boxes to the bars by inserting the metal braces from underneath the ski boxes and using the locking mechanism inside the box to keep them in place. After this, foam was placed into the car boxes for future use and protection and the boxes were left. Below is an ordered timeline of this process.