Tower Assembly

Tower assembly is practically the reverse of tower disassembly. The following procedure assumes that the detector has been removed and the aforementioned disassembly procedure has been followed to conclusion. In other words, the tower base and spool should be fastened together and there should be no connector lid.

The instructions below are complete with steps to include spacers on the tower, if need be. If spacers are not necessary, you may ignore those instructions.

1. Remove the tower from the purge cabinet and place it on the clean bench.
2. Gently clean off any residue from kapton or copper tape with an isopropanol or methanol soaked wipe.
3. Remove two copper spacers (they look like copper rings with 6 equidistant holes) from the purge cabinet and place them on the clean bench.
4. Remove the connector lid from the purge cabinet and place it on the clean bench.
5. Place both the spacers on top of the copper spool such that the six holes line up.
6. Place the connector lid on top of the spacers such that the six threaded holes line up.
7. Use M3 brass screws to fasten the connector lid to the spool. The screws should pass through the holes in the spacers. Use the right-angle screwdriver for this.
   • The screws should be finger tight as you will use a torque driver to ensure a uniform joint.
   • Be careful not to strip the screw heads as this is easy to do. Remember, your screwdriver has a steel head, but the screw is made of brass; a far softer material. In a battle, your screwdriver will win and you will be left with the difficult task of removing the M3 screw. If you feel like you will strip the screw head, stop and try to change position. Do not risk it: it isn't worth it.
   • We have plenty of M3 brass screws on top of the tool cabinet, so change any you suspect are bad: they are very cheap and we can place a next-day order with McMaster Carr for more if necessary.
8. Take the large torque screwdriver and change its head if necessary. Torque all six screws, again being careful not to strip their heads. If you find that you are unable to turn a screw with the torque driver because it is too tight, loosen the screw and try again.

1. Remove the source holder from the purge cabinet and place it on the clean bench.
2. Gently clean off any residue from kapton or copper tape with an isopropanol or methanol soaked wipe.
3. Unfasten the plate holding the Am241 source.
4. Fasten this plate to the opposite side of the housing.
5. The source holder is now ready to be installed on the tower. Place the source holder on the tower and ensure it is well-seated.
6. When viewing the tower from above, the collimation hole for the source should be facing you, and the heads of the screws holding the source to the source plate should be visible. If this is not the case, you have made an error. Please go through the procedure again and find out what went wrong. Please do not look at it for too long: it is a radioactive source and there is a lot of soft tissue in one's head. A quick glance should suffice.

1. Remove the detector from the purge cabinet and place it on the clean bench.
2. Unfasten the connector lid. Start with the six M2 threaded rods. Then turn the detector over and remove the M2 brass Phillips head screws holding the connector lid to the detector housing. Be careful not to strip the heads: they are terribly easy to strip and very difficult to extract should this happen.
3. Examine the detector and identify the phonon channels. The phonon layout diagram on the wall of the clean room will help you in this endeavour. The locations of the DIBs should indicate that you are looking at Side 1.
4. Choose a phonon channel and place the detector housing on the source holder such that the collimation hole for the source lies roughly in the center of this channel. Make a note of the channel.
   • Ensure that the DIBs are placed on tower sides 2, 5 and 6. The tower side is scratched onto the corner of the copper plate that holds the sockets into place on the tower. They should be labelled 16. Only the aforementioned three tower faces work, and failing to do this will involve having to take the tower apart again to move the detector.
   • Keep your fingers away from the wire bonds between the DIBs and the crystal.
   • Lower the crystal very gently onto the source holder. Try to be as straight as possible, but do not worry too much if the mating is not perfect and you need to slide the detector a little. As long as you are gentle, this is perfectly acceptable.
   • If you are unable to sit the detector on the source holder properly, this may be due to the screws of the black detector clamps having rounded heads. The issue can be resolved by replacing said screws with bevelled head screws.
   • Ensure you check the seating to make sure it is perfect.
   • You may need to change the phonon channel as the collimation hole may not lie in the centre of your designated phonon channel.
   • If the three DIBs do not lie on tower sides 2, 5 and 6, pick up the source holder and detector housing together and orientate them such that they do.
   • If it makes your life easier, please feel free to take the source holder off the tower, mate it with the detector housing, and then place both pieces back on the tower.
5. From top to bottom, you should now have the top lid, detector, source housing, connector lid, 2 copper spacer rings, spool and tower base. Check that this is the case. If not, you have done something wrong.
6. Remove the 6 M2 threaded rods, each featuring two nuts, from the purge cabinet and place them on the clean bench.
7. Insert these rods from the top, through the top lid, and detector and source holder housings. With ease, they should fall through and hit the connector lid. You may need to shake them a little while threading them through. If you come across resistance, you have inserted them in the wrong holes.
8. Screw the rods into connector lid. Keep the nuts together to make your task easier. This secures the lids and housings together to form a stack. Use the socket driver (there are two of them in the clean room). They should be finger tight and there is no need to torque them. Do not force them in; if you feel resistance, remove the rod and try again. Ensure the stack is secure, ie. nothing moves. If there is movement, you need to tighten the screws a little further.

1. Mount the tower on its aluminium holder. You will find the support it provides useful for the next stage.
2. Remove three position 4 side coaxes from the purge cabinet.
3. Repeat the following procedure for each side coax:
   1. Attach the SCUHBA extender plugs to the sockets on the tower. Remember that one of the SCUHBA extender plugs requires a copper spacer to lie between it and the tower.
   2. Remove the protector boards covering the pins. They will require gentle coercion. Try not to bend the pins, but this can be rather difficult. If you end up with bent pins, gently guide them back into place with the tweezers.
   3. With the tower upright, insert the pins of the side coax into the sockets on the DIB and SCUHBA extender plugs. There is only one orientation that will allow you to do this.
   4. Ensure all the pins are seated in their respective sockets before pushing the side coax into place. When pushing the side coax into place, apply uniform pressure on both connectors at the same time. By not following these instructions, you may end up bending the pins and/or damage the sockets. If this happens, remove the side coax, straighten the pins with tweezers and try again. If you damage the sockets, try to straighten them out and if they do not hold in place, the connector is severely damaged and must be sent back to Berkeley for repair. Do not allow this to happen (though if it does, it does not mean you are a bad person); take a lot of care and conduct the installation slowly.
   5. Insert 2 long screws through the side coax and SCUHBA extender plug, and fasten the side coax to the tower. On tower face 2, one of the screw holes is blocked so you will only be able to use one screw. They should be finger tight and there is no need to torque them.
4. Once all three side coaxes have been installed, conduct the tower level continuity checks as outlined in Table 2. Do this even if you have been performing continuity checks after installing individual side coaxes to ensure nothing has changed. The resultant table of measured values should be written up on the run diary page. Do not be concerned if the measured values deviate from the typical ones: as long as the difference is not too high, ie. about half-an-order of magnitude, it is acceptable.
5. Attach the adapter plate. The tower is now ready for installation. Perform an electrical check.