Beam/ Halo Diagnostics

R. Fiorito, A. Shkvarunets, H. Zhang

Institute for Research in Electronics and Applied PhysicsUniversity of Maryland

Presented (with apologies)

Michelle Shinn (JLab)

1

Goals: measure low intensity halo properties (distribution and emittance) in presence of high intensity but low emittance core

Approach: use OTR or OSR and optical masking to separate out halo and core

Two masking methods : I. Fixed (pinhole or stop); II. Adaptive (programable digital micromirror array)

OTR and OSR Halo Imaging Systems installed at FEL

Site of OTR and OSR diagnostics

experiments

Electron beam

OTR

Camera 2

Mask

beam imaging

camera

OTR farfield imaging camera

beam( pinhole

or stop )

(farfield OTR gives

localized divergence within

pinhole or outside stop)

I. Fixed Optical Mask (used with OTR station at FEL beam dump)

polarizer

II. Adaptive masking using digital micro-mirror array*

*DLPTM 1100 Texas Instruments Inc.

450

4

micromirror size: 13.68 m x 13.68 m

No of elements: 1024 X 768 pixels

Array switching rate: 9600 patterns / sec

PC interface: USB 2.0

micromirror

Rotation axis

DMA Imaging System Developed at UMD/ UMER

180 Frames

32 m

m

900 Frames

32 m

m

5

Halo measurements at UMER (7 mA beam) using DMA

Screenboundary

Dynamic Range Test of DMD with intense UMER beam and circular mask

20 275 1000

2000 3000

Integration Frames:

7Integration Frames:

32m

m

Dynamic Range Measurement using Circular Mask and intense 23 mA beam: DR ~10(5)

0 50 100 150 200 250 300 350 400 450 50010

-6

10-5

10-4

10-3

10-2

10-1

100

Pixel

Nom

aliz

ed C

ount

0

256

32m

m

8

Reconstructed beam profile

1000 mm

500 mm

OSRPort

(2F06)

Gallery optics: top view

1219

mm

457 mm

DMA

Camera

24o

Optics for DMA Halo Experiment using OSR

(Installed at FEL 8/2010 )

Vault Optics: side view

5 m PVC tube

FEL Vaultceiling

Gallery optics: side view