Download LHC_IR_quads_Heaters

US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
LHC IR Quad Heaters
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Schematic of LHC Inner Triplet 4 IP x (2 Triplets/IP)=8 Circuits
-Q1 and Q3 made by KEK, Q2 made by Fermilab. Q1 and Q3 opposite polarity of Q2.
- “ FNAL” Q2 consists of two 5.5m magnets bussed in series and contained in a single cryostat
-
Series of 8 model magnets + one full scale prototype.
Michael Lamm
2
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Quench Protection Test on Model Magnets
Protection Parameters
-Quench detection threshold 300-500 mV
-Strip heaters provide primary protection
NO EXTERNAL ENERGY EXTRACTION
-Redundancy two circuits (H1&H3, H2&H4)
-Simulate CERN Heater Circuit: 7 mF, 900 V
voltage, RC~100mS, Peak Power >20 W/cm2
Magnet Protection Requirements:
-Peak Temperature <400K
-Peak Voltage to Ground <1000 V
Heater Parameters:
-Heater Insulation
-Heater Width
-Resistance Distribution
-Heater Location
Michael Lamm
3
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Magnet
Position
Element (all 25 m thick)
Insulation
HGQ01
Inter
Stainless steel 15.9mm wide
325uM
Outer
None
N/A
Inter
Stainless steel 15.9mm wide
325uM
Outer
Stainless steel 15.9mm wide
350uM
Inter
Outer
Stainless steel 15.9mm wide
325uM
15.9 mm wide with copper
plating 38 mm etched areas at
114 mm intervals.
350uM
Inter
None
N/A
Outer
12.7 mm wide with copper
plating 610 mm etched areas at
1930 mm intervals.
250uM
Inter
None
N/A
Outer
22.2 mm wide with copper
plating 610 mm etched areas at
1930 mm intervals.
250uM
Inter
None
N/A
Outer
15 mm wide with copper plating
120 mm etched areas at 360 mm
intervals.
250uM
HGQ02
HGQ03 &
HGQ05
HGQ06
HGQ07
HGQ08
HGQ09
Inter
Outer
Michael Lamm
None
Quench protection
program
MQXB
Location
Outer coil 2 mm from midplane
Material
Copper plated stainless steel
Copper thickness
4 m
SS thickness
25 m
Copper Plating
102 mm etched areas at 306 mm intervals
Width
15 mm
Insulation to Coil
225 m
N/A
15 mm wide with copper plating
102 mm etched areas at 204 mm
intervals.
225uM
4
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Two design Parameters: Heater Location and Distributed Resistance
Inter Layer Vs. Outer Layer
Inter Layer
-Outer layer heaters are easier to install
-Inter layer heaters might be more
effective
Longitudinal Resistance
Distribution
-Power supply specs are
fixed, so..what is more
important: larger area
coverage or higher peak
power?
Michael Lamm
Outer Layer
15 mm
9 mm
210 mm
(with copper plating)
105 mm
(without
copper plating)
.21 mm
5
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Using Quench Integral to Study Two Heater Parameters
Quench Integral MIIT's
20.0
Inner vs.Outer
Heaters
15.0
HGQ08 55 W/cm**2
HGQ09 22 W/cm**2
HGQ09 45 W/cm**2
HGQ08 22 W/cm**2
10.0
Longitudinal
Resistance
Distribution
5.0
0.0
0
0.2
0.4
0.6
0.8
1
I/Ic

QI  10 6  I t2 t dt  10 6
0

 1
T peak
A2

T0
c pcomp T '
 Cu T '
dT '
MIIts
Outer heaters just as effective as inner
Quench detection times significant part of quench integral
Longitudinal resistance distribution works
Michael Lamm
6
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Peak Temperature (use spot heaters that simulate spontaneous quenches)
300
Most
pessimistic
quench location tested
with spot heater.
Outer Pole
Inner Pole
250
200
150
400
HGQ07 50 W/cm**2
100
HGQ08 50 W/cm**2
350
50
0
2
4
6
8
Current (kA)
10
Spot heater quenches in
pole turn
12
14
Measured Peak Temperature (K)
Measured Peak Temperature (K)
350
HGQ09 22 W/cm**2
300
HGQ09 45 W/cm**2
HGQ09 no. 2 45 W/cm**2
250
200
150
100
50
0
2.0
Michael Lamm
4.0
6.0
8.0
Current (kA)
10.0
12.0
14.0
7
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Voltage to Ground
120
Opposite heater circuit
Adjacent heater circuit
Peak Voltage (V)
Stainless Steel Only Heater
imbalanced
heater
geometry
80
40
0
2000
5000
8000
11000
The eight coils that
make up a HGQ magnet
are bussed in series,
with inner to outer pole
turn splice. Voltage to
ground is largely due to
resistive-inductive
(im)balance between
inner and outer coils
14000
Current (A)
For 1.9 M model, voltage to ground is low, less than 30 Volts at peak
operating field gradient...
Michael Lamm
8
US LHC ACCELERATOR PROJECT
brookhaven - fermilab - berkeley
Protection Conclusions
Heaters
-Heaters adequately protection magnet from excessive peak temperatures and peak
voltage to ground
-Outer layer heaters are just as effective as interlayer heater. Outer layer heaters
chosen for ease of installation
-Reducing insulation doesn’t seem to have much effect (or small compared to other
variables
-Increasing peak power is more important than longitudinal resistance: use HGQ08
style heater
Bus Work
-Parameterize temperature and velocity
-Single layer stabilizer is adequate. Opt for 1 layer of copper
Michael Lamm
9