1. The HERMES RICH as SBS hadron identification detector
SBS Meeting
JLab : 19/March/2010
JLab 19/Mar/2010 III SBS Meeting
The HERMES RICH as SBS hadron identification detector
DeLeo, Cisbani / HERMES RICH
Evaristo Cisbani / INFN-Rome Sanità Group
Raffaele De Leo / University of Bari and INFN Bari

2. DeLeo, Cisbani / HERMES RICH
Overview of the HERMES RICH
HERMES RICH performances
HERMES RICH in SBS
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH

3. HERMES Experimental Setup
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH
2 RICH identical modules

4. Hadron PID: HERMES RICH
5.5 GeV K+
C4F10 gas
JLab 19/Mar/2010 III SBS Meeting
REAL DATA from NIMA 479 (2002) 511
14.6 GeV e-
1.5 GeV p-
DeLeo, Cisbani / HERMES RICH
Two radiators: aerogel and gas
PMTs as photon detector
Focusing Optics
Reference: NIMA 479 (2002)

5. HERMES RICH module layout
147
JLab 19/Mar/2010 III SBS Meeting 63
101
180 48
DeLeo, Cisbani / HERMES RICH
126
281
unit is cm

6. DeLeo, Cisbani / HERMES RICH
Radiators
JLab 19/Mar/2010 III SBS Meeting
Dirk Rickbosch – DESY07
DeLeo, Cisbani / HERMES RICH
Refractive Index n(633 nm)=1.03
+ C4F10 Gas, n(633 nm)=

7. DeLeo, Cisbani / HERMES RICH
Optics
JLab 19/Mar/2010 III SBS Meeting
Dirk Rickbosch – DESY07
DeLeo, Cisbani / HERMES RICH

8. DeLeo, Cisbani / HERMES RICH
Photon Detector plane
JLab 19/Mar/2010 III SBS Meeting
Dirk Rickbosch – DESY07
DeLeo, Cisbani / HERMES RICH
¾ inch diameter

9. DeLeo, Cisbani / HERMES RICH
Light Collection
Dirk Rickbosch – DESY07
JLab 19/Mar/2010 III SBS Meeting
~20% of the HERMES RICH PMT array
DeLeo, Cisbani / HERMES RICH

10. DeLeo, Cisbani / HERMES RICH
Electronics
Dirk Rickbosch – DESY07
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH
VME based, 20 MHz bus from front-end to VME
less than 30 ms to transfer data to VME
able to keep data up to 800 ns (selectable) since trigger
down to 50 ns gate width
No time information

11. One RICH Module during installation
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH

12. HERMES RICH performances DeLeo, Cisbani / HERMES RICH
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH

13. exp.- calc. angle resolution (%)
HERMES
c for single pe
pe > 5 GeV
Pixel
Mirror
Point emiss
n disp
Chromatic
Forw.Scatt
Surface
Total (calc.)/pe 2.9
Total (exp.)/pe
Npe (exp.)
JLab 19/Mar/2010 III SBS Meeting
Npe = 10
/=3.3%/pe
DeLeo, Cisbani / HERMES RICH
/ = 1.1% /ring
Largest error from pixel size (by design!)

14. DeLeo, Cisbani / HERMES RICH
qC ring  n (e+>5GeV) plot vs day
JLab 19/Mar/2010 III SBS Meeting n
DeLeo, Cisbani / HERMES RICH

15. Dn ≈ 3 *10-4 in 10 years! Dn ≈ 1*10-4 in the last 5 years!
average n (e+>5GeV)
JLab 19/Mar/2010 III SBS Meeting
Dn ~
0.0003
Dn ~
0.0003
DeLeo, Cisbani / HERMES RICH
Dn ≈ 3 *10-4 in 10 years! Dn ≈ 1*10-4 in the last 5 years!

16. pe reconst.starting point distribution DeLeo, Cisbani / HERMES RICH
e > 5 GeV
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH
a real stable RICH !
DNpe < 0.2
0.3% in 10 years!

17. DeLeo, Cisbani / HERMES RICH
HERMES RICH in SBS
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH

18. one RICH module now @ UVa (thanks to Gordon)
JLab 19/Mar/2010 III SBS Meeting
RICH
DeLeo, Cisbani / HERMES RICH
Aerogel Spare
Now stored at UVa under safe/controlled conditions + additional wall of spare Aerogel from the other module.

19. SIDIS (Cond.appr. Exp.): Setup and parameters
e+3He→e’+p(K)+X
JLab 19/Mar/2010 III SBS Meeting
BB: e-arm at 30o
 = 45 msr
GEM Tracker
Gas Cherenkov
Shower
 GMn/PR
SBS: h-arm at 14o
 = 50 msr
GEM tracker
excellent PID / RICH
Hadron CALO
DeLeo, Cisbani / HERMES RICH
Event rate: ~104×HERMES
60 days of production expected stat. accuracy:
10*better than HERMES on proton
Beam: 50 A, E=8.8 and 11 GeV (80% long. Pol.)
Target: 65% polarized 3He  GEn(2)/PR
 Luminosity: 1.4×1037 cm-2s-1

20. HERMES RICH in SBS (SIDIS Exp.)
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH
(old GEM setup)

21. Challenges in large acceptance/high luminosity (SIDIS exp.)
SBS Tracker rate 60 kHz/cm2 (bck, soft photons)
RICH PID: high segmentation of photon detector (2000 PMT):
Expected 35 extra hits/event from soft photons
→ Compton electrons in aerogel (50 ns gate width)  2-5% occupancy
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH
(Jan/2009 estimation)

22. DeLeo, Cisbani / HERMES RICH
To be done
Present RICH performance ?
Characterize the actual RICH and in particular evaluate the aerogel performance (transparency, refractive index …) ?
Simulation
Study rate capability of the RICH
Evaluate required segmentation
Are time information needed? Is the PCOS4 electronics still adequate?
JLab 19/Mar/2010 III SBS Meeting
DeLeo, Cisbani / HERMES RICH