1. RPC Temperature Studies A. Cimmino

2. Temperature Studies 310 temperature sensors are collocated throughout the barrel. Temperatures are monitored by the RPC DCS system online Values are written in OMDS with a 0.3°C dead band (sensor resolution). Temperatures measured during Cruzet3 & 4 were analyzed and are here presented. The behavior of each single sensor has been studied.

3. Average Temperature for 3 Wheels during Cruzet3 Wheel0 appears to be the hottest one at all times In 6 days the average temperature of the wheels increases of ~ 1 -1.5°C as you may see from the next slide 62 sensors/Wheel

4. Temperature Distribution for 3 Wheels at the beginning and end of Cruzet3 Black = 07/07/2008 2pm Red = 13/07/2008 2pm While the average temperature is below the critical value (23°C) our concern are due to these tails

5. Average Temperature Plot and Distribution for Reference sensors during Cruzet3 Compatible with a horizontal line

6. Possible heating sources RPC FEB LVs DT FEB & MiniCrate LVs ECAL Cables(???)

7. What happens if RPC LVs are turned off? LVs OFF from 09/07/2008 7pm Slopes measured in °C/day (8.5 ± 1.1) * 10 -2 (11.5 ± 1.3) * 10 -2 (9.0 ± 1.2) * 10 -2 (9.9 ± 1.3) * 10 -2 (9.3 ± 1.1) * 10 -2 ~1°C every 10 days of increase DT minicrates ON

8. What happens if DT LVs are off? Data from Cruzet4 DT LV off the entire period on Sectors 6 & 7 Wheel-2 RPC FEBs ON

9. DTemp with DT OFF & RPC ON °C Temperature increase distribution after 5 days with DT LVs OFF

10. W-2 Sector 4 RB1in & RB1out Temperature with DT&RPC ON DT ON – Cruzet4 Weekend = RPC ON & DT OFF ~ 2.5 °C of increase during Cruzet 4 week --------- ~1.5°C of increase in the first day

11. Temperature of water during Cruzet 4 °C Sensor stopped reading ~2.5 hours

12. Cooling Schema Flow-limiters 1.5 liter/minute 1.5 x 50/2 = 37 l/min/wheel

13. Cooling Cooling water is shared by 2 adjacent sector Sectors are twined as shown in the tables INOUT 1211 109 87 65 43 21 INOUT 121 23 45 67 89 1011 Wheels +1,0,-1,-2 Wheel +2 IN OUT RB4 RB3 RB2 RB1 RB2 RB3

14. DTemp between RB4 and RB1in Even Sectors Odd Sectors

15. Temperature Distribution by Stations RB1in RB1out RB2 RB3 RB4 Temperatures refer to the 11/07/2008 2pm