1. Prototype sPHENIX Calorimeters
John Haggerty
Brookhaven National Laboratory
10/24/2013

2. The sPHENIX Experiment
Major upgrade to the PHENIX Experiment at RHIC
Primary purpose is to measure jets in heavy ion collisions
Measure jet energy using calorimetry
Good solid angle coverage (|h|< 1, Df=2p)
Provide a basis for a future detector at eRHIC
Study nucleon structure and QCD in nuclei over a broad range of x and Q2 using deep inelastic polarized ep and eA collisions

3. HCAL
Magnet
EMCAL
Solenoid
10/24/2013

4. 10/24/2013

5. Calorimeter Requirements
Large solid angle coverage (± 1.1 in h, 2p in f)
Moderate energy resolution
EMCAL ~ 15%/√E
HCAL ~ 75 %/√E (single particle), ~100 %/√E (jet)
Compact (for EMCAL  small RM, short X0)
Physically small (dense) – occupies minimal space
High segmentation for heavy ion collisions
Hermetic
Projective (approximately)
Readout works in a magnetic field
Low cost

6. EMCAL Tungsten-SciFi Accordion
SBIR
Tapered thickness pure tungsten metal plates with scintillating fiber layer glued in between
2 W plates/layer  0.6 X0 sampling
~ 10 cm
18 X0
Pure tungsten metal sheets (r ~ 19.3 g/cm3) Thickness: 2x1.0 mm
Epoxy (~ 0.1 mm)
Scintillating fibers
1.0 mm
X0 = 5.3 mm
RM = 15.4 mm

7. Test of simpler “tilted plate” design 1 mm W + 1 mm scintillator
EMCAL prototype
Test of simpler “tilted plate” design
1 mm W + 1 mm scintillator
10/24/2013

8. Towers are formed by Light Collection Cavities
White reflecting epoxy between plates
22 mm
3D printed light collection cavities
3x3mm SiPM
8x8 tower readout board with 2x7 light collection cavities

9. Light yield from prototype measured with cosmic rays and PMT readout
Light Yield From Fibers
Light yield from prototype measured with cosmic rays and PMT readout
500 g/MeV energy deposit in scintillator
8 % sampling fraction  40 x 103 g/GeV (Edep in calorimeter)
Light Collection Factor (2%)  800 g/GeV
SiPM PDE ~ 0.25  200 p.e./GeV
 7%/√E contribution to energy resolution

10. sPHENIX Hadron Calorimeter
60 cm
3.5 labs
30 cm
1.5 labs
4 inner and 4 outer plates joined together to form one section
Steel plates with scintillating tiles parallel to beam direction
Steel serves as flux return
Steel plates are tapered
 Sampling fraction changes with depth
Divided into two longitudinal sections
Measure longitudinal center of gravity to correct for longitudinal fluctuations
Plates tilted in opposite directions to avoid channeling

11. Fibers read out with SiPMs
HCAL Readout
Scintillating tiles with WLS fibers embedded in grooves
Fibers read out with SiPMs T
2x11 segments in h (Dh =0.1)
64 segments in f (Df =0.1)
1408 x 2(inner,outer) = 2816 towers
2x11 scintillator tile shapes
Inner
Outer
Inner readout
(~10x10 cm2)
Outer readout
SiPMs + mixers
8 readout fibers per tower

12. HCAL Scintillator Tiles Manufactured in Russia
White reflective coating
(chemical etching)
WLS fiber embedded in grove in tile (top and bottom)

13. Light Collection for HCal
10/24/2013

14. HCAL Tile Measurements at the University of Colorado
Light output and uniformity measurements of scintillating tiles
Top fiber
Bottom fiber
S.Beckman
Light Yield ~ 18 p.e./”mip” (measured with 90Sr)

15. HCAL prototype
10/24/2013

16. Beam Test of the Combined EMCAL/HCAL Prototypes
Scheduled to take place in the MT6 test beam at Fermilab in Feburary 2014

17. sPHENIX
10/24/2013

18. HCAL Prototype Construction at BNL

19. Readout Electronics EMCAL Prototype readout board
HCAL Readout Electronics System

20. Electronic chain test
10/24/2013

21. Calorimeter beam test
10/24/2013

22. Summary
PHENIX is planning a major detector upgrade to replace its existing Central Arm Spectrometer with a new calorimeter system consisting of an electromagnetic and hadronic calorimeter
These new calorimeters will enable a detailed systematic study of jets produced in heavy ion collisions at RHIC to study the QGP near its transition temperature
Both calorimeter designs are well under way and prototypes of both calorimeters are currently under construction
A combined test of both prototype calorimeters is planned to take place at Fermilab in February of next year