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Future IR Heating Issues. 13 December 2004 Stan Ecklund. IR Heating Issues - Overview. Since Last Review (April) MD data with Vertex Bellows cooling off and Data on bunch length dependence of HOM power. New improved chiller system for cooling water. Status HOM Heating
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Future IR Heating Issues 13 December 2004 Stan Ecklund MAC Review – Future IR Heating Issues
IR Heating Issues - Overview • Since Last Review (April) • MD data with Vertex Bellows cooling off and • Data on bunch length dependence of HOM power. • New improved chiller system for cooling water. • Status • HOM Heating • Vertex Bellows 2002 Cooling is working well – Power now 500 W • Q1/Q2 Bellows • Larger HOM absorbers in 2002. • Will need to improve HOM/Power capability - now 11 KW • Synchrotron Radiation • LEB B1 Fan Hits LEB Leg of Q2 Crotch and Q4 chamber • May be cause of magnet motion (~20 microns). • New Q4 chamber, bellows and Q5 chamber • HEB – B1 fan aimed at High Power Dump must miss Q5R chamber flange. New Q5R chamber. MAC Review – Future IR Heating Issues
Near IR MAC Review – Future IR Heating Issues
IR Vacuum Chambers MAC Review – Future IR Heating Issues
Forward Vertex Bellows – Before Cooling Hottest Point according to model (300 C) T_VTX2 Thermocouple ( dT = 105 F = 58 C) Beryllium Vertex Chamber B1 Chamber MAC Review – Future IR Heating Issues
Forward VTX BLWS Cooling MAC Review – Future IR Heating Issues
Thermocouple Locations T_V0B270 On Ta foil, z=blws-70mm -y x=0,z=113 mm T_V1B270 Al Clam, end near IP, -y, theta=270 z=157 T_V2B270 Al clam, corner theta=270, z=17.5 T_VTX2 TC1: Forward alum clamshell (+y) T_V3B000 Inboard end of blws theta=0 T_V3B135 Inboard end of blws theta=135 T_V3B180 Inboard end of blws theta=180 T_V3B225 Inboard end of blws theta=225 T_V3B270 Inboard end of blws theta=270 T_V3B_O Inboard H2O out, -x +y T_V4B_O1 Collar H2O out -x T_V4B_O2 Collar H2O out +x T_V5B000 SS end of B1 Chamber theta =0 T_V5B180 SS end of B1 Chamber theta =180 T_V3B_AI Air in Bellows, top T_V6B_AI Air btwn B1 chamber & magnet,+y,z=295mm,slice3/slice4 MAC Review – Future IR Heating Issues
VTX Bellows Cooling Installation MAC Review – Future IR Heating Issues
Vertex Bellows Cooling Added in 2002 is still working • Increased Currents: From 1500 on 1000 to 2450 on 1500 • Shorter Bunch Length • dT=reduced by factor of 2.7 • Time constant 100 sec vs. 220 before • OK with today’s increased currents and till 2006 plan. • Next design needs cooled absorber MAC Review – Future IR Heating Issues
Vertex Bellows Absorber Design MAC Review – Future IR Heating Issues
Erratic Behavior Similar to Before MAC Review – Future IR Heating Issues
Cooling off T_VTX2Forward Vertex bellows • Step Change at 1400 ma • Step -0.004 out of 0.034or 12% • From bellows motion? • Data in Blue • Fit in Red • Time constant 221 sec • Linear term 0.00985 • dT = 14 F at 1400 ma • HOM term = 0.0341 • dT = 44 F at 1400 ma MAC Review – Future IR Heating Issues
Cooling off Summary MAC Review – Future IR Heating Issues
Backward and Forward Vertex BLWS Temperatures MAC Review – Future IR Heating Issues
Thermo Model (May 2001) for 100 Watts Power input behind fingers.Does not match data in detail. MAC Review – Future IR Heating Issues
LER Bunch Length MD • Vary Vrf = [2.9, 3.2, 3.8, 4.5, 4.8 MV], ILER =[500, 1000, 1400] • Fit T(t) = T0 + L * ILER + LHOM * (ILER2 / Nb) *(Vrf /3.8 MV) • Exponential time response of temperature • Good fit with above form with linear RF gap voltage driving HOM • For hottest TC T_VTX2 L = 0.0024 degF/ma LHOM = 0.0123 degF/ma2 With out cooling LHOM = 0.0341 ( 2.77 times larger) Projects to for LER HOM heating (add about 34% - 24% for HER): Jul 2004 LER 2500 ma, V=3.8 MV , HOM dT= 44 F Jul 2005 LER 3300 ma, V=5.4 MV , HOM dT= 110 F Jul 2006 LER 3900 ma, V=7.7 MV , HOM dT= 219 F Jul 2007 LER 4500 ma, V=7.7 MV , HOM dT= 291 F MAC Review – Future IR Heating Issues
Vrf I LER MAC Review – Future IR Heating Issues
Bellows Power July 2004 • Taken from max – min of Thermocouples HSTB data during a typical day • TC on water out tubes • Turbine flow meter measures water flow • Mass flow meter measures air flow • VTX 416 Watts • Q1/Q2: 11 KW MAC Review – Future IR Heating Issues
Measured and Projected Power MAC Review – Future IR Heating Issues
LEB+HEB HOM Power ~ S ib2sz-2 MAC Review – Future IR Heating Issues
Be Vertex Pipe and Bellows MAC Review – Future IR Heating Issues
Synchrotron Radiation – Backward LER B1& Q1Fans LEB side,+x,y=0, small Cu finger, z=-2.8 m LER Q4 vac, +x, z=-3.64 next to flange • LER Leg of Q2 Crotch chamber and Q4 chamber • dT=84 F / 2250 ma. • Suspect this is cause of observed magnet motion. • Working on ways to improve cooling on LER Q2 and Q4 chambers with additional cooling. MAC Review – Future IR Heating Issues
LEB Fans MAC Review – Future IR Heating Issues
HEB Fans – new Q5 chamber MAC Review – Future IR Heating Issues
New Chiller Water System • Improved Reliability • Heat exchange to IR2 Chiller with 4 units • Mixing valve and pump • New Allen-Bradley controllers • Better Temperature Control • Heaters in hall for 10 individual water circuits can respond to changes in beam heating quickly. • Sensors on IR vacuum chambers can control heaters. • Full Flow strainer • Larger Capacity • From 20 to 50 KW • Project completed this summer • Some Programming work remains to be done. MAC Review – Future IR Heating Issues
Future IR Heating Issues - Summary • HOM Heating • Planned increase in bunch current and decrease in bunch lengths drive up HOM heating dramatically. • Increase in heating may be less if bunch length increases with bunch current. • Vertex Bellows: • 2002 cooling works up to 1.8 A HER on 3.3 A LER • Add absorber to new design in next long downtime with ST removal. • Q1/Q2 Bellows • Now taking out 11 KW • Expect power to increase to 22 KW • Working on design to handle higher power. • Synchrotron Fan Heating • Backward LEB Q2 Leg and Q4 chamber needs solution for cooling/motion • Plan to take more Data to better characterize heating dependence on bunch length, bunch current, number of bunches,… • Improve VTX Beryllium diagnostic. • New Vacuum chambers • Spare forward Q2 chamber • Radial Ion pump • Q1/Q2 Bellows with improved power capacity • VTX Bellows with absorber • Q4, Q5 chambers … MAC Review – Future IR Heating Issues