TJNAF Hall A HRS Lead-Glass Shower Calorimeter

Plane 1: 48 Pb-glass blocks (10cm x 10cm x 70cm) with TF-1 glass
Information taken from A Brief Description and Operating Guide of the Preshower Detector by Ashot Gasparian and Hakob Voskaniani, October 12, 1995.

Yerevan TF-1 glass:
- Composition: 51.2% PbO; 41.5% SiO
- Radiation length: 2.74cm
- Refractive index: 1.647
- Density: 3.86 g/cm^3
- Critical Energy: 17.5MeV
- Nucl. Absorption Length: 22cm
PMTs: Hammamatsu R3036 three inch tubes
- Dynode structure / number of dynodes: B&L/12
- Voltage at a gain of 1E6: 1.1-1.4kV
- Single p.e. Resolution (lambda / A): 50%
- Pulse height resolution (Cs137 with NaI crystal): 7.3%
- Rise time: 7ns
- Transit time (for 1.1kV): 54ns
- mu-metal shields are used on tubes
Pairs of blocks touching end to end, mounted transverse to central ray.
3.65 radiation lengths
Array of 2x24 long blocks gives area: 700mm x 2400mm
Each module (2 blocks + tubes + etc) weighs(measured): 63.8 lbs (28.9 kg)
Each module (2 blocks + tubes + etc + right angle SHV adapters) is 110cm long

Energy Deposition
Type of particle	Energy deposited (in MeV)
Cosmic rays	65-70
1GeV e-	300
4GeV e-	700
1GeV straight through pion	65-70
1GeV showering pion	420
4GeV straight through pion	65-70
4GeV showering pion	?

Light Output and Collection
Particle type	Energy (in GeV)	Light Output	Number of photoelectrons
Cosmic rays	2	?	61
e-	1	?	300(?)
e-	4	?	?
pion, straight through	1	?	60
pion, showering	1	?	?
pion, straight through	4	?	?
pion, showering	4	?	?

Form of signal from cosmic rays
	Anode	Dynode
Duration	100ns	80ns
Rise time	40ns	40ns

Plane 2: 96 Pb-glass blocks (14.64x14.64x35 cm^3) with Schott SF5 glass

bought from CERN-UA2
Schott SF5 glass:
- Radiation length: 2.38cm
- Refractive index: 1.6727 (587.6nm wavelength) 1.7107 (404.7nm wavelength)
- Density: 4.08 g/cm^3
- 5.765 inches square(measured)(=14.64cm)
- weight of block (calculated): 67.5 lbs
PMTs: Philips XP2050 five inch without mu-metal shields
- 5.125 inches diameter
weight of block plus PMT attached (measured): 69.3 lbs
Blocks mounted longitudinally (parallel to central ray)
Array of 6x16 blocks gives area: 900mm x 2400mm