1. GEM, applications for SR experiments and tracking in HEP
Lev Shekhtman
Budker INP

2. DIMEX – Detector for Imaging of EXplosions
OD4 – One-dimensional detector for WAXS (wide
angle X-ray scattering)
SRRE – tagging system for KEDR experiment
at VEPP-4M

3. Motivation

4. The detector requirements
Time resolution ~100 ns
Spatial resolution ~0.1 mm
Detection efficiency >50% for 20 keV photons
Photon rate capability 1010 – 1012 s-1mm-2

5. Detector design White SR beam from 2T wiggler at 2GeV, Eav~20keV
Drift electrode
White SR beam from 2T wiggler
at 2GeV, Eav~20keV
GEM
Strips
Length = 30 mm
Pitch = 0.1 mm
Xe-CO2(80-20) 7atm

6. DIMEX
DIMEX1
Station “Explosion” at
VEPP-3 SR bunker

7. Detector for imaging of explosions (DIMEX) is developed with
the following parameters:
Time resolution ~40ns (charge collection time constant),
frames separation 500ns, frame duration ~250ns, number
of frames 32;
Spatial resolution ~0.19mm (FWHM), number of channels 256,
channels pitch 0.1mm;
Dynamic range ~100, limiting rate (incident) is
~10000 ph/chan/bunch~
~1012ph/mm sq./s, DQE (measurement) ~25%
(for white SR beam with 0.1mm Al filtration)

8. Density distribution in the detonation wave
4 frames with the images of running detonation wave

9. Diffraction studies at SR beam

10. OD-4 2048 channels 0.2mm pitch 67o aperture 350mm focus distance
Eg = 5-10keV

11. OD-4

12. OD-4 Single channel efficiency 8 keV, Ar-CO2(75-25) Channel responsemm
Single channel efficiency
8 keV, Ar-CO2(75-25)
Channel response

13. Tagging system for KEDR
e- , p1
e+ , p2
p'1
p'2
Рис.1 Двухфотонное взаимодействие e+ e-
Electrons that lost their energy
in two-photon interaction are
bent out from the orbit and
pass through coordinate stations
(TS1-TS4)
Two-photon interaction

14. GEM detector for the tagging system

15. GEM detector for the tagging system

16. GEM detector for the tagging system
final detector(2006)
prototype (2001)
Signal correlation

17. Position-sensitive and tracking detectors
with GEM.
DIMEX – GEM is used for shielding of ions and attenuation
of the signal. Operating for 4 years.
OD4 – triple-GEM with arc shape. Full-size detector with
partly equipped readout structure
Tagging system – 8 triple-GEM detectors with special small
angle stereo readout. All detectors are
installed on the collider, one shoulder is
fully equipped and operating