The following three SWAMP crates were exchanged: rack 2, crate 2, rack 5, crate 3 and 4. In each crate every second slot holds a SWAMP motherboard giving a total of four SWAMP motherboards in each crate. The empty slots are covered with plates. Each SWAMP motherboard holds 20 channels, and all channels contain SWAMP cards. The delay chips were removed from the old SWAMP cards and put on the new cards. In the back each SWAMP motherboard is connected to a pick-up box. Each pick-up box holds two layers of pick-up cards. The upper layer contains 10 pick-up cards corresponding to the ten even channels, and the bottom layer contains 10 pick-up cards corresponding to the odd channels. We also changed the quad connectors for strings 5-13.
The quads have been labeled with string number, quad number and OMs in string, for example '07Q08-21/22' which means OMs 21 and 22 in quad 8 for string 7. The connectors have been labeled with string and quad, for example '07Q08'. In strings 11-13 the quads have only been labeled with string and quad number.
We brought two empty SWAMP motherboards as spares and these are mounted in rack 9, crate 2. There are 33 spare SWAMP cards, of which 30 have delay chips and 3 do not. They have been put on the metal shelf in MAPO. There are also two spare pick-up boxes on the shelf, and one pick-up box with only 16 pick-up cards that should be be used to take spare pick-up cards from. In a cardboard box on the metal shelf there is also a spare power supply (without casing), some spare fans, extra screws and spare pick-up cards. In another box marked 'Connector kits' there are spare connectors and finally there's also a cardboard box marked 'SWAMP tools' that contain different tools for removing quads, changing connectors, setting gain etc. All old crates, SWAMP cards and connectors have been sent back to Stockholm.
To summarize, the system we installed this year consists of:
In the hardware data base the first quad in string 9 was marked down as 'missing' but we found it. It is too short to reach down to the crates and someone has therefore extended it with a thinner quad denoted 22. On the end a connector labeled '20Q22' was attached with a note saying 'polarity unresolved'. We resolved the polarity, attached a connector with correct labeling and reconnected the quad. However, we were unable to raise the high voltage of OMs 265 and 266, and the problem seems to be a damaged quad.
In string 10, 5 quads (quads 2, 7, 10, 14 and 15) that were connected according to the hardware data base turned out to be disconnected in reality. However, these OMs were all working in run 5920 from October 2002. The OMs have high voltage and seem to be working fine and have hence been reconnected.
In string 8 there are three test OMs, 195, 197 and 199 (OMs 1,3 and 5 in string 8) that are dead since before, and now they have been removed physically by cutting the cables in the connector. Hence the connectors for quads 08Q18, 08Q17 and 08Q16 only hold one OM each (and these are working fine). The removed test OMs have low to high voltage convertors in the actual OMs, and the reason for removal was either that the conversion has failed or that the LV supply on the surface is to noisy.
OMs 81-86 in string 4 used to have HV=0 V and they have been non-functional for a long time. The old SWAMPs were not optimized for these OMs but since the upgrade they are working fine. We have given all six of them high voltage (see the list of revived OMs below) and they are given nice pulses and good ADC and TDC spectra.
In string 13 some of the OMs were connected in a strange way. In rack 1, crate 1, slot 07 the string 13 quads were connected in falling order, starting with quad 21 down to quad 16. Then the second OM in quad 15 was connected whereas the first OM in the string was not (these were old connectors were the quad was split into one connector for each OM). Instead the second OM in quad 15 was followed by both OMs in quad one and then the first OM in string 14 and finally both OMs in quad 2. We connected all quads.
We had some problems with last years pick-up cards. One card was giving noise (high ADC) in OM 430 (OM 2 in string 14) in rack 9, crate 9, slot 01, channel 02. The pick-up card was removed and replaced by a new card taken from one of this years spares (marked 'Spare No 1 of 1'). This solved the problem with the high noise rate.
Another card was giving a lot of noise (high ADC) in OM 331 (string 11) in rack 1, crate 1, slot 02, channel 05. The entire pick-up box (marked 'B13 03/06') was replaced by a spare. The faulty box has been repaired but has not been put back. Once again, changing the pick-up card solved the problem with high noise rate.
Right now there's one perfectly fine spare (marked 'B10 07/14'), one spare that is used to take cards from ('Spare No 1 of 1') and finally the spare in rack 1, crate 1, slot 02, that should be replaced by the repaired box 'B13 03/06'.
OM 558 (OM 4 in string 17), located in rack 9, crate 9, slot 07, channel 19 was noisy in both ADC and TDC. When opening it turned out that the SWAMP card was connected between channel 19 in the front and channel 20 in the back, that is the card was bent. We put in a new SWAMP card in channel 20 which solved the problem. The previously bent card was put into an empty channel in the same slot (channel 13) and seems to be working in it's unbent state. A new SWAMP card was also put into channel 19.
We encountered big problems with the M1 1440 LeCroy power supply. Sometimes communication failed and sometimes the actual voltage value for a channel differed from the demand and back-up values. This caused the ADC peak to shift.
During a run one channel suddenly lost high voltage and the value could not be reset. Next it was impossible to raise the voltage of any channel in the same card in the power unit. When removing the card from the power unit and replacing it with a spare, we discovered that one channel in the card had burnt and that the entire card was marked 'do not use'. Changing cards solved the problem. All high voltage cables were put back in their correct positions.
All OMs below were dead before the upgrade but are now working.
Most of the OMs below have HV=0 V for some unknown reason and it should be investigated wether they can be revived or if they are permanently dead. The remaining OMs have broken optical read-out, but functional unused electrical read-out.
Some OMs were disconnected for no appearent reason. Many of these were actually working in runs in October 2002, but were disconnected in November 2002. We decided to reconnect these.
These OMs have problems that we have been unable to solve, or are odd in some way.
This is not a complete list over dead OMs, but only the three test OMs in string 8 that are dead and have now been removed physically inside the connector.
For some OMs we changed the high voltage in order to get a better ADC spectrum. There is also a text file with all high voltage changes summarized.
A brief survey has revealed mainly three noise frequencies. Some 16 seconds after turning on either of the 1458 LeCroys a 8 MHz noise appears. How this noise is picked up and how it depends on distance etc has not been determined. It also turns out that some (bad) SWAMP cards give rise to, or are very good at picking up, 1.2 MHz and 100 kHz noise.
All changes have been entered in the data base.