Details on temperatures

The AC system of the shed is made of two cooling units, a heating unit and a controller connected to two temperature sensors : one located in the shed and one located in the BSY. This system is programmed in such a way that the temperature of the shed follows the BSY temperature within +-2C. The BSY temperature can be anywhere in the [18C,35C] range, regardless of the season. The BSY temperature and the shed temperature are given (in F) by a display panel located close to the workstation, on the wall. The AC system can be set in manual control by turning from "auto" to "manual" a set of switches controlling the cooling units and the heater unit. These switch boxes are located on the shed wall. If the shed temperature is above 34.4C (94F), call Arun Saha (the electronics can be damaged) and cool down the shed in manual AC mode. The 4 temperature sensors of the probe are labelled Tx+z+, Tx+z-, Tx-z+, Tx-z- depending on their position w.r.t. the following (x,z) frame:

                                      x 

                                      ^ 

                                      | 

                                      | 

Door$<-$-           $<-$------D I P|O L E -----$->$ 

                                      | 

                   $<-$--Tx+z- ----|---Tx+z+---$->$ 

                   |                  |                 | 

                   |                  |-----$->$z     | 

                   |                                    | 

                   |              P R O B E             | 

                   $<-$--Tx-z- -------Tx-z+---$->$

Both "x+" sensors are on the probe edge which is inside the dipole gap and both "x-" sensors on the opposite edge which is outside the dipole gap. Both "z-" sensors are at 1/4 of the long dimension of the probe and both z+ at 3/4 of this length. The average of the 4 temperatures is used by the analysis program to correct the coil distance from the thermal expansion of the probe, so it is important to make sure that the 4 sensors are working well. The user can just make sure that the temperatures displayed in "arc-master.adl" or recorded in "arc-integral.adl" are realistic. In "arc-integral.adl" they are given in the order: Tx+z-, Tx+z+, Tx-z-, Tx-z+ Tx-z- and Tx-z+ should be close to the shed temperature. Tx+z- and Tx+z+ depend on the probe position, as the gap (iron yoke) is warmer than the shed and the dipole coil (at both ends of the dipole) is warmer than the iron yoke. For a probe in a central position for more than about one hour, the Tx+z- and Tx+z+ sensors should give the yoke temperature, i.e the shed temperature plus 0. to 5.C, depending on the current, LCW temperature and the magnet/shed temperature history. The 4 temperatures are also displayed inside the shed, on the electronics rack. These values are digitized by separate ADCs, so they may differ from the remote values by 0.1C.