The RICH power supplies are classified as high voltage (HV) and low voltage (LV) powers. The HV power supplies are used to bias the detector. The LV supplies (analog +5 V, analog -5 V and digital +5 V) are for front end electronics.
While the HV power budget is relatively easier to be estimated, the LV power budget is a conservative estimation as the front end electronics boards, especially the multiplexer board are still under design. We assume that power budgets of each hybrid (FEH) are 0.10 A, 0.20 A and 0.19 A for analog +5 V, analog -5 V and digital +5 V respectively. These values are measured with a HPD hybrid. A MAPMT hybrid has less channels thus needs less power. On the other hand the power regulation scheme is also different. On conservative side we use the same as that of a HPD hybrid. The multiplexer board (FEM) uses +5 V power only. It should contain a FPGA, two memory chips, and drivers for data lines. The power consumption is expected to be similar to a PTA board. Thus we allocate a 0.3 A budget. Also note that for analog powers are down regulated to 2 V. We can use power lower than 5 V to reduce save power.
We plan to use CAEN A 1518A as LV power supply. It provides 6 channel 0-4.5V with maximum current of 6 A.
There are 944 HPDs grouped in 6 HPD hexagonal modules, with some modules not fully populated as shown in hpd_iden_xp.eps and hpd_iden_xn.eps . The modules are indicated in different colors except for the last column. One HPD connects to one front end hybrid (FEH). Each 6-HPD module are served by one front end multiplexer (FEM) except for high occupancy region, where 2 or even 3 FEMs are used to have an optimized data load. In total there are 944 FEHs, and 200 FEMs.
Both the HV and LV powers will be provided through a set of cables per module row. For example, the two HPD rows contain HPD 28,29,58,59,...,441,442,471,472 need 4 HV and 4 LV cables/channels. We use two LV channels for digital +5 V because of the current limit. Each set of HV and LV channels serves ~32 HPDs, ~32 FEHs and ~7 FEMs. In total the HPD system needs 30×4 = 120 HV channels and 30×4 = 120 LV channels.
Ideally HPD consumes negligible HV power. We will provide an 1 GΩ load, thus a 20 KV line consumes 20 μA.
HPD power budget:
| Power supply name | Voltage value | Current/channel | Number of channels | Total current | Total power |
| HPD Cathode | -20 kV | 20 μA | 30 | 0.60 mA | 12 W |
| HPD Focus | -19 kV | 19 μA | 30 | 0.57 mA | 11 W |
| HPD Zoom | -16 kV | 16 μA | 30 | 0.48 mA | 8 W |
| HPD silicon bias | +75 V | 4 mA ? | 30 | 120 mA | 9 W |
| Analog +5 | +5 V | 3.1 A | 30 | 94 A | 470 W |
| Analog -5 | -5 V | 6.3 A | 30 | 190 A | 950 W |
| Digital +5 | +5 V | 4.0 A | 60 | 240 A | 1200 W |
In total there are 9016 MAPMTs arranged in two 49×92 arrays, one on each side. There are 1196 FEHs, each connects to 4×2 MAPMT tubes as shown in mapmt_ifeh_q4.eps for 1/4 of total MAPMTs. A 2×2 array of FEHs is connected to one FEM, i.e. each FEM serves 8×4 MAPMT tubes. At high occupancy region, two FEMs are used to optimize the data load, as shown in mapmt_ifem_q4.eps. For more details on the grouping please see Data Transfer page.
The MAPMT tubes will be mounted to base boards. Each base board houses 4×4 MAPMTs (2 FEHs). The height of base board corresponds to a supporting bar. In current design each MAPMT has its own voltage divider ladder which consumes 0.35 mA (0.35 W) power. We have the option to share a divider among several MAPMT tubes. However, to maintain enough standing current the power consumption per tube remains the same and it will not affect our budget estimation in this note.
Each MAPMT base board will be supplied by one HV channel. The only exception is the last column that the base board is 1/4 populated. These boards share HV channel with their neighboring base board. In total we will have 12(column) × 23 (row) × 2 (side) = 552 HV channels/cables, each provides -1 KV with at least 5.7 mA (5.7 W). The total HV power budget is 3100 W.
The LV will be provided per 4 MAPMT rows. That is 26 FEHs and 7-8 FEMs will be supplied by a set of 4 LV channels/cables, with digital +5 V uses two LV channels. In total there are 46 sets of LV channels.
MAPMT power budget:
| Power supply name | Voltage value | Current/channel | Number of channels | Total current | Total power |
| MAPMT Cathode | -1 kV | 5.7 mA | 552 | 3.2 A | 3200 W |
| Analog +5 | +5 V | 2.6 A | 46 | 120 A | 600 W |
| Analog -5 | -5 V | 5.2 A | 46 | 240 A | 1200 W |
| Digital +5 | +5 V | 3.6 A | 92 | 327 A | 1600 W |
There are 4948 PMTs arranged in 4 arrays on 4 sides of the RICH vessel, connected to 98 FEHs and 24 FEMs as shown in pmt_iden_xp.eps , pmt_iden_yp.eps , pmt_ifem_xp.eps , and pmt_ifem_yp.eps . More details can be found in Data Transfer page.
Each FEHs connect to about 8×8 = 64 PMTs. And 4 FEHs connect to 1 FEM. This scheme, however, may be changed. Especially that we have not decided whether to use 3" tube or 2" tube. The estimation here just provide a rough idea.
Each PMT has an 8-stage HV divider which consumes 0.29 mA (0.35 W) -1.2 kV power. One HV channel will connect to roughly 4 × 4 = 16 PMTs. At the edge of the PMT arrays more PMTs are connected to one HV channel. In total 12×7+12×6+12×7+12×6 =312 HV channels are needed. Each channel provides -1.2 kV with at least 4.6 mA (5.6 W).
We will use 1 set of LV channels for each of the four sides of PMTs (X+, X-, Y+, Y-). A set of LV channels/cables include analog +5 V, analog -5 V and two digital +5 V, similar to that of HPD and MAPMT. In total we need 16 LV channels.
PMT power budget:
| Power supply name | Voltage value | Current/channel | Number of channels | Total current | Total power |
| PMT Cathode | -1.2 kV | 4.6 mA | 312 | 1.44 A | 1750 W |
| Analog +5 | +5 V | ~2.5 A | 4 | 10 A | 50 W |
| Analog -5 | -5 V | ~5 A | 4 | 20 A | 100 W |
| Digital +5 | +5 V | ~3.2 A | 8 | 26 A | 130 W |