HXRSS Design Status

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25 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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HXRSS Design Status

P. Emma
et al

Feb. 25, 2011

1

2

Figure 1 of the paper…

Taper last 10 undulators
for 100
-
GW power level

1
-
m
洠牭猠
e
-

pulse length (3 fs)

“…introduces no path delay of x
-
rays”

Taper works better

3

HRXSS Physics Requirements Document:

Electron & FEL parameters (
e.g.
, 20 pC)

Chicane parameters

Magnet requirements

Crystal with position/angle controls

Vacuum chamber requirements

Bragg diagnostic requirements

All tolerances

4

2.6 mm

60 cm

60 cm

New HXR Self
-
Seeding Chicane for the LCLS Undulator (~U12)

Q
U
A
D

Q
U
A
D

3.4 m

Q
U
A
D

Q
U
A
D

B
F
W

|B
0
|

≈ 3.34 kG,
R
56

= 12
m
m,
c
D
t

= 6
m
m,
h
max

= 2.6 mm,
q

= 2.67 mrad

ELEVATION VIEW

PLAN VIEW

Q
U
A
D

Q
U
A
D

Remove one segment and add chicane (1.5 Å, 13.64 GeV)

B
F
W

BPM

BPM

BPM

e
-

B
F
W

0
-
80 mm

chicane raft

B3

B1

B4

B2

36
cm

36
cm

36
cm

36
cm

3.20 m

58 cm

Beam Finder Wire

e
-

crystal

provides 0
-
40 fs delay

5

32 mm

alignment
stage

chicane raft

motor

0
-

80 mm

80 mm

e
-

beam with dipoles
ON & inserted

e
-

& x
-
ray beam with
dipoles retracted

existing girder

356 mm

8 mm

alignment stage

chicane raft

existing girder

existing horizontal slider

cross
-
sectional view

elevation view

x
-
ray beam with
dipoles inserted

2.6 mm

6

v

q

CCD camera

YAG screen (>0.3
-
mm thick?)

crystal

transmitted x
-
rays

incident x
-
rays

Bragg reflected
x
-
rays

0.1 mm

vacuum window

f

FEL Wavelength Range:


l
r

=
1.4 to 1.7 Å (somewhat arbitrary)

Bragg Crystal Angles :


q

=
51.7
°

(1.4 Å) to 72.4
°

(1.7 Å)

Camera Viewing Angles

:


f

=
2(
p
/2
-

q
)
=
=
㌵⸲
°
=
t漠㜶⸶
°
=
⠾㐱
°
)
*

* Compromise: Allow camera viewing only from 1.4 to 1.6 Å or
f

=
77.6
°

to 51.4
°

(~27
°

range)

7

HXRSS Chicane Dipole Magnet Design is Ready

D. Walz


0
-
6 A


576 main coil turns


±
1% trim coils (
±
6 A)


No water cooling


~50 W/magnet


0.02
°

C tunnel rise

8

Possible 4
-
Axis Diamond Positioning System

D. Shu (ANL)

9

Possible HXRSS Layout at U15 (or U16)

J. Amann (SLAC)

D. Shu (ANL)

Sliding raft to
move all 4
dipoles IN or
OUT (8 cm)

Crystal chamber
(ion pump must
move)

10

Issues

Do we place it at U15 or U16 (need ~1 GW seed)?

Will we lose power in SASE mode (25% so far)?

Can the chicane be tweaked to fix the phase error?

Is a 0
-
40 fs chicane OK (
i.e.
, only 20
-
40 pC supported)

OK to have 2.6
-
mm crystal
-
to
-
electron hor. clearance?

Commissioning plan started, but needs more thought.

Existing LCLS monochromator only measures 10
-
4

BW.
This will have to suffice OK for now?

What will go wrong and how do we avoid it?

11