Helge Ravn CERN Muon week, 08/05/01 1 Target and Pion Collection System and Support Facility CERN...

Helge Ravn CERN Muon week, 08/05/01

1

Target and Pion Collection System and Support Facility

CERN Target and Horn working group

Http://cern.ch/Helge.Ravn/files/Muon week Talk

CERN 10 May 2001


2

The E951 Collaboration

CERN Target and Horn working group

A. AUTIN, A. BALL, A. BERNADON, L. BRUNO, A. FABICH, G. GRAWER, S. GILHARDONI, T. KURTYKA, J. LETTRY, J.-M. MAUGAIN, H. RAVN, M. SILARI, P. SIEVERS, N.VASSILOUPOULOS, V. VLACHOUDIS, H. VINCKE and F. VOELKER


3

CERN reference scenario

• In order to produce 1021 neutrinos/year proton beams with a power of 1-4 MW needs to interact with a high Z target.

• Proton energy 2.2 GeV.

• Repetition rate 50 Hz

• Pulse duration 3.3 s.

• Pulse intensity 1.5 1014/pulse

• Average beam power 4 MW

• Target absorbed power 1 MW

• Liquid Hg-jet target Diam.10 mm

• Pion collection by means of a magnetic horn.


4

Heat load comparison• Radioactivity laboratory and

support facility similar to.

• EURISOL

• RIA

• ESS, SNS

• Nuclear waste transmutation


5

Thermal expansion waves in ISOLDE targets

• Splashes threshold (Pb, Sn and La targets 1993):

– 11013 protons per pulse, 20 bunches (h=5)– 0.5 1012 protons per bunch (~60ns, 1GeV)

ISOLDE target system


6

Thermal expansion wave and cavitation


7

Simulations

(R. Samulyak)

Surface evolution due to the interaction with proton pulses


8

Why a Mercury-Jet• High pion yield (high Z)

• High source brightness (high density)

• Flowing liquid have excellent power handling capabilities

• No water radiolysis

• Liquid at ambient temperature (no liquid-to-solid phase change issues)

• Minimal waste stream (compared to solid alternatives)

• Passive removal of decay heating

• No dominant long-lived radiotoxic products

• No confinement tubing (free flowing jet)

• No beam windows (differential pumping confinement)


9

Hg-jet system• Power absorbed in Hg-jet 1

MW

• Operating pressure 100 Bar

• Flow rate 2 t/m

• Jet speed 30 m/s

• Jet diameter 10 mm

• Temperature- Inlet to target 30° C- Exit from target 100° C

• Total Hg inventory 10 t

• Pump power 50 kW


10

BNL CERN Trough test• Perpendicular velocities of Hg-”drops” via high speed cameras

(8000 frame/s, 25s aperture and up to 1000 kframe/s, 0.15s aperture)

– 0.5-4.01012 protons per bunch,– Bunch length 100 ns– Proton energy 26 GeV

• Results (preliminary)

– 6 to 75 m/s splashes measured (under atm. pressure)

– Scales with the number of protons in the bunch

• Questions

– Response to a multi-bunch pulse (CERN scenario)

– Response to a bunch length reduced to 3-5 ns

– Response to other dE/dx


11

Timing : 0.0, 0.5, 1.6, 3.4 ms, shutter 25 s

11stst P-bunch1.81012 ppb

150 ns

BNL E-951 trough test8 kHz camera

Vsplash ~20-40 m/s


12

BNL E-951 trough test1MHz camera

Timing [ms]0.0, 0.2, 0.40.6, 0.8, 1.0

shutter 150 ns

P-bunch4.01012 ppb

150 nsVsplash ~75 m/s


13

BNL Hg-jet chamber• P-bunch:

26 Gev,

• spot size: r=1.6x0.8 mm (rms),

• intensity <4 10^12 protons per bunch

• bunch length 150 ns

• Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/sprep. velocity ~ 10 m/s


14

Jet test at BNL E-951 #4 25th April 2001

P-bunch: 3.81012 ppb100 nsto = ~ 0.45 ms

Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/sprep. velocity ~ 10 m/s

Picturestiming[ms]0.0000.2500.5000.1750.4250.9753.000


15

Jet test at BNL E-951 #1125th April 2001

P-bunch: 2.71012 ppb150 nsto = ~ 0.45 ms

Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/sprep. velocity ~ 5 m/s

Picturestiming[ms]0.000.754.50

13.00


16

Magnet field injection test 13T


17

13T Magnet field mapGrenoble high magnetic field laboratory:vertical Solenoid Bmax=13 Tobserved maximum gradient dB/dz=49.5 T/mpulsed mercury jet, d=4mm, v=4-15 m/sMeasurements in 20 T field planned for Sept. 01


18

Simulations

(R. Samulyak)

Surface evolution due to the interaction with magnetic field


19

Comparison without/with magnetic field- pictures taken with 0,1 ms shutter-speed (at 1000 fps)- all frames 48 ms after trigger of valve

without field: 0 T, v = 4.6 m/s

with field:49.5 T/m, v = 4 m/s


20

CERN Trough test1/5 of the Neutrino factory beam power-densities can be obtained in the 1.4

GeV BOOSTER/ISOLDE p-beam

PSB-ISOLDE3.21013 protons per pulse, 20,8,4 bunches (h=5,2,1 )Pulse length 2.4 s (-20 s staggered extraction)Proton energy 1 GeV

Trough test at CERNHg tight sealing ~ 40 pulses. Response to bunch up to 81013 ppB.Response to beam size and beam energy.Disposal of Hg via amalgams ?


21

CERN/ISOLDE In-Beam Experiment

2965

11 68

1208

- at ISOLDE Target Area

p beam

frontend

Hg container

mirror

camera


22

0

1

0 0.6 1 .2 1 .8 2 .4

2.4 s proton pulse h=5

0

1

0 0.6 1.2 1.8 2.4

h=1

Time [s]

tS tS

0

1

0 0.6 1 .2 1 .8 2 .4

protons [a.u.]

h=2

NufactNufact

140 bunches 1.151012 ppBbunch length 5 nsp-energy 2.2 GeVPulse duration 3.2 sPulse intensity 1.61014 ppp

PSB-ISOLDEPSB-ISOLDE

4 bunches 8.01012 ppBbunch length 200 nsp-energy 1,1.4 GeVPulse duration 3.2 sPulse intensity 3.21013 ppp

“velocities-pressure” benchmarks for simulation


23

Nu-fact Trough experiment at ISOLDE q 1.60E-19

protons_per_ C 6.25E+12Goal : Irradiation of 1.3 cm3 Hg (16g) contained in a ssteel box with quarz windows by PSB proton pulses.The ssteel box himself is contained in a vacuum tight box.

Radioactive waste production of the Hg trough vs. an ISOLDE Pb target 1 to 100000

Nu-fact Hg Target thickness 13 g/cm2Z 80

Proton beam Energy 1 and 1.4 GeV

Lead / Hg trough Ratio2 x 3 pulses each at pulse intensities 5.0E+12

8.0E+12 Target thickness : 171.2E+13 Integrated p-beam : 57971.5E+132.0E+13 R-waste or Dose rate : 981052.5E+133.0E+13

average ppp: 1.6E+13number of pulses 42tot N protons 6.9E+14microC 110

Expected contact dose rate (1 month cooling) 0.0003 mS/h

ISOLDE Lead target thickness 220 g/cm2Z 82Proton beam tot N protons 4.00E+18microC 640000

Contact dose rate 1 day after irradiationContact dose rate after 1 month cooling 30 mS/hComparative RIB production (see next worksheets)

Radiation safety of trough test


24

Magnetic Horn

• Units H40-400

• Type mm 40-400

• Waist radius mm 40

• Peak current in horn kA 300

• Total capacitance

• for 1 switching section µF 1453

• Duty cycle Hz 50

• Pulse duration

• (half period) µs 93

• Charging voltage V 6283

• Voltage on horn V 4200

• r.m.s. current in horn kA 14.5

• PH

Mean power dissipation

• in horn by current * kW 39.

• Water flow needed

• in l/min with w= 15°C * l/min 3power dissipation due to beam absorption to be added

L

R

C

CU0L

i

i / m

m

U0 / m

= 20 ms

Figure 1: basic circuit

i

R

Lp Ls

Tc

T/2

IM

U0


25

Water-cooled granular target• P. Sievers/CERN

Ta-Spheres, = 16.8 g/cmR = 1mmPacking density ~60% (~140 spheres/cm3)R = 10g/cm3

Small spheres good for cooling: surface/volume~1.RWater cooling:v = 6m/s through 20% of cross-sectionV = 11l/sT =18K (20% of 4MW, S. Gilardoni)T =36KP =4-5 BarRe ~ 104


26

Continuation of R&D• Test the Hg-jet in a 20 T magnetic field

• Systematic trough tests in the ISOLDE 1- 1.4 GeV proton beam

• Development of jet hydrodynamic models

• Improve the speed and hydrodynamic stability of the Hg-jet

• Building of a prototype horn and test heat transfer coefficient at the inner conductor and if possible the lifetime.

• Start preliminary engineering study of the integration of the plumbing of the target and the spent beam absorber in the horn.

• Design and build a continuos flowing Hg-jet set up for in-beam tests.

• Continue the study of alternative target concepts like radiation cooled solids and the water cooled granular target.

Date post:	18-Jan-2016
Category:	Documents
Upload:	barnaby-williams
View:	221 times
Download:	4 times

Helge Ravn CERN Muon week, 08/05/01 1 Target and Pion Collection System and Support Facility CERN...

Documents