1. Resume of the experimental program up to date
Hao Zhang

2. Previous Summary
We successfully use the supersonic gas jet to monitor beam profile in ionization mode.
We have a tool to measure the jet density which can be used to benchmark the simulation.
Still make progress on the BIF mode.

3. Status up to date Proof-of-principle result of BIF mode
Gas curtain distribution study
Faraday cup installation and its result
Lab move and resume of the experimental program

4. BIF monitor based on supersonic gas jet
First &Second skimmers
180 mm & 400 mm
Off centred nozzle hole
Nozzle
30 mm
7.2 mm *1.8 mm
4.0 mm * 0.4 mm
Third skimmers

5. Generation of supersonic gas jet

6. Vacuum consideration Number 1 2 3 4 6 Jet off (mbar) <5.0*10-4
2.1*10-6
9.7*10-8
1.8*10-8
5.36*10-10
Jet on (mbar)
5.5*10-3
6.9*10-5
4.8*10-6
2.3*10-8
1.21*10-9

7. Pump and Gauge Scroll Pump Turbo Pump Pirani Gauge Ion Gauge Number
Brand
Type
Pumping Speed 1
ScrollVAC
SC5D
5 m3/h 2
SD30D
30 m3/h 3
SD15D
15 m3/h 4
Number
Brand
Type
Min pressure 1
Laybold Thermovac
TTR91 DN16KF
5*10-4 mbar
Number
Brand
Type
Min pressure 2
Laybold Ionivac
Sensor IE514
2*10-12 mbar 3 4
Pfeiffer
PBR260
5*10-10 mbar 5 6
Brand
Type
Pumping Speed* 1
Pfeiffer
TMU200MP
180 L/s 2
Leybold
SL300
270 L/s 3
Hipace80
67 L/s 4
SL700
690 L/s 5 6
*based on N2 gas.

8. Details on the interaction chamber
s (cross section)
9.2*10-19 cm2
I (electron current)
~10 uA
n (gas jet density)
2.5*1010 cm-3
d (jet thickness)
2.8 mm
Ω(acceptance solid angle)
4π·10-5 sr
hpc(MCP photocathode efficiency)
0.2
hMCP(MCP detection
efficiency)
0.5
T(Transmittance of optics)
0.65
Tf(Transmittance of band pass filter)
0.3
Blackened firstly by a Germany Company and then applied another layer of Graphite
Ng = 0.08*Dt

9. Gas jet image from fluorescent50
100
150
200
250
Shutter time: 8000s, MCP 1.0 V
E-gun: 2.6A filament current
3.5keV energy
X: 6.70, Y: 6.40, Focus: 5.55
Reflection of the hot cathode or E-beam on the tube joint
ROI y x
Residual gas image
141 mm
Axis
BIF
IPM
Xrms
1.96 mm
1.2 ± 0.2 mm
Yrms
1.33 mm
0.4 ± 0.2 mm
Compared to the Ionization mode
1pixel = mm

10. Why so long integration time
1000s integration time is still good enough.
Interaction cross section is low
Photon transfer efficiency is not perfect
Optics loss (lens and viewport)
Bandpass filter loss
MCP efficiency
E-gun intensity is low
Unknown (manual says 8uA when filament is 2.6A at E = 3.5keV)

11. Edge scan (large skimmer)
Skimmer size
7.2×1.8 mm2
Oriental angle
45˚
Iion(X,Y)
Resolution: 1pixel = 0.2mm
4.5 mm
14.7 mm
15.2 mm
15.2 mm
19.2 mm
19.2 mm
Differentiate the data in horizontal axis
Jet size in interaction point is estimated as : mm * 2.81 mm
sjet = 0.99 mm

12. Beam enlarged by jet thickness
View point
View point
ebeam
ebeam
Beam size mm
sx (Gas jet)
0.5 ± 0.2
sy (Gas jet)
Beam size mm
sx (Gas jet)
0.4 ± 0.2
sy (Gas jet)
1.2 ± 0.2
sjet = 0.29 mm
sjet = 0.99 mm

13. Faraday cup

14. Lab move Over one month’s waiting for the move
2 weeks for the electrician to install the power sockets
IPAC
Filament replacement of the old gun

15. After move experiments
BIF test with the old E-gun after filament change.
Previous steering location not work.
Scanning the electron beam again? Still suffer from the long integration time.
Change to new E-gun or New optics?

16. Summary We demonstrated BIF monitor based on supersonic gas jet.
Further study of gas jet density under a larger skimmer continues to validate the measurement method and strengthen the understanding of the jet density distribution under different skimmer sizes.
Faraday cup study showed the gun behave better than the manual for large filament current.
Recover from lab move is still undergoing.