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13 Dec. 2004 MAC Review – Future IR Heating Issues 1
Future IR Heating Issues
13 December 2004
Stan Ecklund
13 Dec. 2004 MAC Review – Future IR Heating Issues 2
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.
13 Dec. 2004 MAC Review – Future IR Heating Issues 3
Near IR
13 Dec. 2004 MAC Review – Future IR Heating Issues 4
13 Dec. 2004 MAC Review – Future IR Heating Issues 5
IR Vacuum Chambers
13 Dec. 2004 MAC Review – Future IR Heating Issues 6
Forward Vertex Bellows – Before Cooling
T_VTX2 Thermocouple( dT = 105 F = 58 C)
Beryllium Vertex Chamber B1 Chamber
Hottest Point according to model (300 C)
13 Dec. 2004 MAC Review – Future IR Heating Issues 7
Forward VTX BLWS Cooling
13 Dec. 2004 MAC Review – Future IR Heating Issues 8
Thermocouple LocationsT_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
13 Dec. 2004 MAC Review – Future IR Heating Issues 9
VTX Bellows Cooling Installation
13 Dec. 2004 MAC Review – Future IR Heating Issues 10
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
13 Dec. 2004 MAC Review – Future IR Heating Issues 11
Vertex Bellows Absorber Design
13 Dec. 2004 MAC Review – Future IR Heating Issues 12
Erratic Behavior Similar to Before
13 Dec. 2004 MAC Review – Future IR Heating Issues 13
Cooling off T_VTX2
Forward Vertex bellows
• Step Change at 1400 ma – Step -0.004 out of 0.034
or 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
13 Dec. 2004 MAC Review – Future IR Heating Issues 14
Cooling off Summary
13 Dec. 2004 MAC Review – Future IR Heating Issues 15
Backward and Forward Vertex BLWS Temperatures
13 Dec. 2004 MAC Review – Future IR Heating Issues 16
Angular Dependence Total T (F) at 1400 ma
60
70
80
90
100
110
120
130
-60 0 60 120 180 240 300
Angle (degrees)
V3B
V5B
V3A
V4A
V5A
13 Dec. 2004 MAC Review – Future IR Heating Issues 17
13 Dec. 2004 MAC Review – Future IR Heating Issues 18
Thermo Model
(May 2001)
for 100 Watts Power input
behind fingers.
Does not match data
in detail.
13 Dec. 2004 MAC Review – Future IR Heating Issues 19
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
13 Dec. 2004 MAC Review – Future IR Heating Issues 20
Vrf
I LER
13 Dec. 2004 MAC Review – Future IR Heating Issues 21
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
13 Dec. 2004 MAC Review – Future IR Heating Issues 22
Measured and Projected Power
13 Dec. 2004 MAC Review – Future IR Heating Issues 23
LEB+HEB HOM Power ~ ib2 z-2
13 Dec. 2004 MAC Review – Future IR Heating Issues 24
Be Vertex Pipe and Bellows
13 Dec. 2004 MAC Review – Future IR Heating Issues 25
Synchrotron Radiation – Backward LER B1& Q1Fans
• 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.
LEB side,+x,y=0, small Cu finger, z=-2.8 m LER Q4 vac, +x, z=-3.64 next to flange
13 Dec. 2004 MAC Review – Future IR Heating Issues 26
LEB Fans
13 Dec. 2004 MAC Review – Future IR Heating Issues 27
HEB Fans – new Q5 chamber
13 Dec. 2004 MAC Review – Future IR Heating Issues 28
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.
13 Dec. 2004 MAC Review – Future IR Heating Issues 29
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 …